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Doxil (R) - The first FDA-approved nano-drug: Lessons learned
Abstract
Doxil®, the first FDA-approved nano-drug (1995), is based on three unrelated principles: (i) prolonged drug circulation time and avoidance of the RES due to the use of PEGylated nano-liposomes; (ii) high and stable remote loading of doxorubicin driven by a transmembrane ammonium sulfate gradient, which also allows for drug release at the tumor; and (iii) having the liposome lipid bilayer in a "liquid ordered" phase composed of the high-T(m) (53 °C) phosphatidylcholine, and cholesterol. Due to the EPR effect, Doxil is "passively targeted" to tumors and its doxorubicin is released and becomes available to tumor cells by as yet unknown means. This review summarizes historical and scientific perspectives of Doxil development and lessons learned from its development and 20 years of its use. It demonstrates the obligatory need for applying an understanding of the cross talk between physicochemical, nano-technological, and biological principles. However, in spite of the large reward, ~2 years after Doxil-related patents expired, there is still no FDA-approved generic "Doxil" available.
... Through the functionalization of the phospholipids, the liposome surface can be easily modified with any kind of recognition element, such as proteins [12], antibodies [13], DNA [14,15], peptides [16], and small molecules [17]. Therefore, they have evolved to play an essential role in the pharmaceutical [18], food [19], agricultural [20], and cosmetic industry [21] as carrier systems for the protection and delivery of molecules [22]. Liposomes are particularly important in drug delivery [18] and received a lot of attention through their use as a platform for the COVID-19 vaccine [23]. ...
... Therefore, they have evolved to play an essential role in the pharmaceutical [18], food [19], agricultural [20], and cosmetic industry [21] as carrier systems for the protection and delivery of molecules [22]. Liposomes are particularly important in drug delivery [18] and received a lot of attention through their use as a platform for the COVID-19 vaccine [23]. In bioanalysis, they are used as signal amplification means by entrapping large quantities of marker molecules, for instance, fluorescent, chemiluminescent, and electrochemically active compounds, or enzymes [12,14,15,24]. ...
Liposomes are a well-established carrier and controlled release system in medicine and bioanalysis. Their biomimetic capabilities are harnessed for the development of a reliable homogeneous assay platform technology that lends itself to high-throughput screening and point-of-care applications since no wash or separation steps are needed. It was developed for fluorescent, chemiluminescent, and electrochemical detection strategies and applied to antibodies directed against small or polymeric molecules and peptides as model analytes. The simplicity of the approach is achieved as mere binding of analytes or analyte-associated entities to the liposome surface leads to the activation of the complement system, which in turn lyses the liposomes. Released encapsulated marker molecules are quantified and directly correlated to the analytes. Control over the liposome chemistry, including cholesterol content, surface chemistry, and encapsulants, was identified to be key to ensure their general serum and storage stability (more than 40 months at 4 °C and up to 4 weeks at 37 °C) and their efficient and specific response to complement activity. Additional assay conditions of relevance included the concentration of liposomes and their ratio to serum proteins, the amount of complement trigger per liposome, and the activity of complement proteins. Understanding and being able to control the liposomes enable various analysis strategies including the quantification of analytes, determination of complement activity, and evaluation of the therapeutic application potential of antibodies. A time-resolved version of the assay even allows the study of the complex actions of the complement system.
Graphical Abstract
... There are several types of nanomaterials being used widely, such as solid-lipid nanoparticles, liposomes, and polymers (Montesinos et al., 2021). As of today, only few nanomedicine products have gained US Food and Drug Administration (FDA) approval, and Doxil and Abraxane are the two most successful nano-formulations already widely used for breast cancer treatment in clinical trials (Barenholz et al., 2012;Minckwitz et al., 2013). It is expected that strong collaboration with experts in pharmacokinetics, toxicology, immunology and oncology will become essential. ...
Breast cancer is one of the life-threatening diseases in women worldwide, leading to the mortality of millions of people all around the world. The objective of this review is to discuss various strategies for breast cancer treatment. The increased prevalence of breast cancer globally in recent years has increased challenges to clinicians. The availability of appropriate detection tools for early detection is the major part of the clinical management of breast cancer patients in the present situation. Together with the current imaging techniques, molecular biomarkers based research has gained huge attention in disease management. Chemotherapeutic drugs significantly reduce the mortality rate of breast cancer. Over past few years, substantial advances has been made in the discovery of cytotoxic, hormonal and targeted drugs for treating breast cancer. The therapeutic response is dependent on a variety of factors, including stages, subtypes, metastasis, etc. Toxicity and chemotherapy resistance are major limitations in the treatment of patients with Breast Cancer. Further study is needed in order to maximise benefit, whilst minimising toxicity.
... Due to their physicochemical properties, LNPs are able to penetrate various barriers inside the human organism [45,50,51]. Therefore, drugs based on LNPs can prolong the effect of the active substance [52,53], modify pharmacokinetic properties, improve pharmacological properties, and increase bioavailability [54]. From an immunological perspective, the delivery of drug substances comprising RNA poses a significant challenge, the resolution of which would facilitate the development of novel vaccine formulations [51]. ...
Nanoparticles (NPs) represent a unique class of structures in the modern world. In comparison to macro- and microparticles, NPs exhibit advantages due to their physicochemical properties. This has resulted in their extensive application not only in technical and engineering sciences, but also in pharmacy and medicine. A recent analysis of the scientific literature revealed that the number of articles related to the search term “nanoparticle drugs” has exceeded 65,000 in the last decade alone, according to PubMed. The growth of scientific publications on NPs and nanomaterials (NMs) in pharmacy demonstrates the rapidly developing interest of scientists in exploring alternative ways to deliver drugs, thereby improving their pharmacokinetic and pharmacodynamic properties, and the increased biocompatibility of many nanopharmaceuticals is a unique key to two mandatory pharmaceutical requirements—drug efficacy and safety. A comprehensive review of the literature indicates that the modern pharmaceutical industry is increasingly employing nanostructures. The exploration of their physicochemical properties with a subsequent modern approach to quality control remains the main task of modern pharmaceutical chemistry. The primary objective of this review is to provide a comprehensive overview of data on NPs, their physicochemical properties, and modern approaches to their synthesis, modification of their surface, and application in pharmacy.
... Doxorubicin was by far most used drug, often serving as a prototype drug to validate the effect of the combination therapy upon combining it with a second and/or third drug. This finding is in line with current clinical practice, as doxorubicin is very widely used and was historically the first chemotherapy drug that was approved in liposomal formulations (that is, Doxil/Myocet) 14,15 . Other drugs that have been very extensively used are paclitaxel and https://doi.org/10.1038/s41565-025-01932-1 ...
Multi-drug nanomedicine is gaining momentum for co-delivering more than one drug to the same site at the same time. Our analysis of 273 pre-clinical tumour growth inhibition studies shows that multi-drug nanotherapy outperforms single-drug therapy, multi-drug combination therapy, and single-drug nanotherapy by 43, 29 and 30%, respectively. Combination nanotherapy also results in the best overall survival rates, with 56% of studies demonstrating complete or partial survival, versus 20–37% for control regimens. Within the multi-drug nanomedicine groups, we analysed the effect of (co-)administration schedule and strategy, passive versus active targeting, nanocarrier material and the type of therapeutic agent. Most importantly, it was found that co-encapsulating two different drugs in the same nanoformulation reduces tumour growth by a further 19% compared with the combination of two individually encapsulated nanomedicines. We finally show that the benefit of multi-drug nanotherapy is consistently observed across different cancer types, in sensitive and resistant tumours, and in xenograft and allograft models. Altogether, this meta-analysis substantiates the value of multi-drug nanomedicine as a potent strategy to improve cancer therapy.
... Despite their small size (1-100 nm), NMs provide a large surface-to-volume ratio for biomolecule assembly, thus increasing the potency of the drug (Cao et al., 2021). A major milestone in the revolution of pharmacology was marked in 1995 with the FDA approval of polyethylene glycolated liposomal doxorubicin (Doxil), which is now used for treating several cancers (Barenholz, 2012). NMs are designed according to the tumor's etiology to effectively combat drug resistance. ...
A notable increase in cancer-related fatalities and morbidity worldwide is attributed to drug resistance. The factors contributing to drug resistance include drug efflux via ABC transporters, apoptosis evasion, epigenetic alterations, DNA repair mechanisms, and the tumor microenvironment, among others. Systemic toxicities and resistance associated with conventional cancer diagnostics and therapies have led to the development of alternative approaches, such as nanotechnology, to enhance diagnostic precision and improve therapeutic outcomes. Nanomaterial, including carbon nanotubes, dendrimers, polymeric micelles, and liposomes, have shown significant benefits in cancer diagnosis and treatment due to their unique physicochemical properties, such as biocompatibility, stability, enhanced permeability, retention characteristics, and targeted delivery. Building on these advantages, this review is conducted through comprehensive analysis of recent literature to explore the principal mechanisms of drug resistance, the potential of nanomaterials to revolutionize selective drug delivery and cancer treatment. Additionally, the strategies employed by nanomaterials to overcome drug resistance in tumors, such as efflux pump inhibition, multidrug loading, targeted delivery to the tumor microenvironment, and gene silencing therapies are discussed in detail. Furthermore, we examine the challenges associated with nanomaterials that limit their application and impede their transition to clinical use.
... Therefore, macromolecules with smaller pores are more likely to spread into tumor cells through tumor blood vessels, thus achieving targeted drug transport [13]. For example, Doxil was the first FDA-approved nanomedical drug that uses EPR effects as a therapeutic mechanism to passively target tumors [14]. This drug wraps adriamycin hydrochloride in liposomes and passively targets tumors through EPR effects and releases adriamycin into tumor cells. ...
Cancer is often treated by surgical intervention, in later stages needs adjuvant chemotherapy or radiation therapy. The position of cervix is easy for drug to localized delivered through the vagina, which directly targets the action site, decreasing the dosage and systemic side effects. This method is good for fertility maintenance, because it allows for the removal of smaller tumors, thereby lowering the risk of premature labour. Additionally, localized delivery post-surgery can help greatly reduce recurrence rates, providing a better fertility protecting results compared to traditional surgery. This paper summarizes the development of targeted drug delivery systems in the past five years, and the results show that targeted drug delivery can improve the therapeutic efficiency of drugs and reduce side effects by improving drug accuracy and reducing side effects. In addition, various targeting methods are discussed, including passive targeting, physical targeting, active targeting. Their respective roles in improving therapeutic effectiveness are also be discussed. There are two main problems encountered during drug delivery, one is the ability to carry enough drug to treat, this will be solved by the choice of liposomes to be used and the second is the ability to protect the successful delivery of the drug to the organ that needs to be treated, and to solve this problem will be aided by the further addition of Carbopol as well as other substances to the liposomes. the main approach used in this article is the different methods used to prepare liposomes with different substances to counteract the substances in the vagina.
... In recent years, nano-drug has experienced rapid development in disease prevention and treatment. The United States has already approved the market release of liposomal formulations of Amphotericin B, DOX, and Daunorubicin, while paclitaxel nanoformulations have also been applied in clinical disease treatment (Barenholz 2012). Compared to traditional chemotherapy drugs, nano-drug can enhance the solubility of poorly soluble drugs and prolong their half-life in the body. ...
As an antineoplastic antibiotic, doxorubicin (DOX) effectively inhibits RNA and DNA synthesis. However, its application is limited by side effects and drug resistance. This study established a xenograft mouse model of breast cancer (BC) to investigate the therapeutic efficacy of a gene/drug nano-delivery system combining vascular endothelial growth factor (VEGF) silencing with DOX for treating BC. Poly (lactic acid) (PLA) was utilized as the carrier material to prepare nanoparticles (NPs) loaded with VEGF interference RNA (siRNA) and the chemotherapeutic drug DOX (PLA/DOX-NPs and PLA/DOX-siVEGF-NPs). The characterization and drug release of NPs were analyzed. NPs’ cytotoxicity was determined by CCK-8 assay with HUVEC and MCF-7 cells. The BC xenograft (BCX) model was established by injecting MCF-7 cells into the mammary fat pads of nude mice. The differences in tumor weight and tumor inhibition rate were analyzed after treatment with DOX alone, PLA/DOX-NPs, and PLA/DOX-siVEGF-NPs. Immunohistochemical staining was employed to examine Ki-67 positive expression rate in the BCXs. Western blot was used to detect Ki-67 and VEGF protein expression levels in transplanted tumor tissues. Additionally, a suspension of BCX cells was injected subcutaneously into healthy nude mice to assess tumor growth after secondary engraftment. Both PLA/DOX-NPs and PLA/DOX-siVEGF-NPs demonstrated sustained release of DOX in buffer media at varying pH values, with no visible difference in inhibiting human umbilical vein endothelial cells (HUVECs) proliferation. After establishment of the BCX mouse model, compared to DOX group, the PLA/DOX-NPs group and PLA/DOX-siVEGF-NPs group exhibited a significant reduction in relative tumor volume and Ki-67 index, along with an increased tumor inhibition rate. Furthermore, after secondary tumor formation, both tumor volume and size were markedly reduced (P<0.05). There were statistically significant differences in various parameters between the PLA/DOX-NPs group and the PLA/DOX-siVEGF-NPs group (P<0.05). The prepared PLA/DOX-siVEGF-NPs demonstrated low toxicity to normal cells and strongly inhibited the proliferation of MCF-7 BC cells in vitro. Moreover, PLA/DOX-siVEGF-NPs effectively inhibited the growth of BCXs in nude mice and suppressed Ki-67 positive expression. This treatment also reduced the malignant differentiation of the tumors and inhibited tumor recurrence. Key words: xenograft mouse model, doxorubicin; nanoparticles; breast cancer; vascular endothelial growth factor.
... The U.S. Food and Drug Administration (FDA) has approved several nanomedicine formulations for cancer treatment [87]. Notable examples include Doxil [88], Myocet™ [89], and DaunoXome [90]. Additionally, nanoparticle formulations like Abraxane [91], approved for metastatic breast cancer, advanced non-small cell lung cancer, and metastatic pancreatic cancer, have also received FDA approval. ...
Cancer remains one of the deadliest diseases globally, significantly impacting patients' quality of life. Addressing the rising incidence of cancer deaths necessitates innovative approaches such as nanomedicine and artificial intelligence (AI). The convergence of nanomedicine and AI represents a transformative frontier in cancer healthcare, promising unprecedented advancements in diagnosis, treatment, and patient management. This narrative review explores the distinct applications of nanomedicine and AI in oncology, alongside their synergistic potential. Nanomedicine leverages nanoparticles for targeted drug delivery, enhancing therapeutic efficacy while minimizing adverse effects. Concurrently, AI algorithms facilitate early cancer detection, personalized treatment planning, and predictive analytics, thereby optimizing clinical outcomes. Emerging integrations of these technologies could transform cancer care by facilitating precise, personalized, and adaptive treatment strategies. This review synthesizes current research, highlights innovative individual applications, and discusses the emerging integrations of nanomedicine and AI in oncology. The goal is to provide a comprehensive understanding of how these cutting-edge technologies can collaboratively improve cancer diagnosis, treatment, and patient prognosis.
... In fact, liposomes are currently the most successful nanomedical devices. Since the FDA approval of the first liposome formulation, Doxil® (Barenholz 2012), numerous liposome formulations have been approved (Crommelin et al. 2020). Despite the great success of liposomes for several drugs, their potential is not fully realized due to the limited number of drugs that are compatible with liposome encapsulation (Balouch et al. 2021). ...
Anammox bacteria wield an energy‐efficient nitrogen metabolism enveloped in anammoxosome organelle composed of unique ladderane lipids. Thus, waste anammox biomass seems to be an attractive target for the isolation of ladderanes and subsequent production of artificial vesicles for drug delivery. This study proposed a novel method to isolate ladderane‐rich anammoxosomes from aggregate mixed culture of Ca. Brocadia sapporoensis. Compared to conventional isolation protocols, the protocol was simplified by omitting the prepurification of anammox cells, replacing Percoll® with a sucrose gradient and prolonging the application of EDTA. This enhanced and simplified procedure efficiently removed EPS and other debris, thus yielding the layer of anammoxosomes as confirmed by control experiments and TEM. For the first time, the resulting ladderane isolates were used for the preparation of liposomes, both with and without the addition of pure dipalmitoylphosphatidylcholine (DPPC). Vesicles were successfully created, characterised by TEM and DLS, and anammox‐based ladderanes were incorporated into their walls. These liposomes had interesting functional properties such as increased colloid stability at elevated concentrations, meaning a reduced tendency to form aggregates compared to model liposomes made solely of DPPC. Overall, this study offers insights into converting waste anammox biomass into a valuable resource for drug delivery.
... There's also the risk of the drug unintentionally leaking from the nanoparticles, which could affect treatment outcomes. (Barenholz, 2012;Allen and Cullis, 2013;Patil and Jadhav, 2014;Inglut et al., 2020;Gbian and Omri, 2022). The cytotoxicity of nanoparticles (NPs) hinges on multiple factors. ...
Turmeric, also referred to as Curcuma longa, is a commonly used spice, recognized for its demonstrated effects in reducing inflammation, combating microbes, providing antioxidant benefits, slowing the aging process, and exhibiting anticancer potential. The process of skin aging is intricate, with ultraviolet radiation being a significant extrinsic factor. Increasing evidence suggests that curcumin, the active component of turmeric, can prevent ultraviolet radiation-induced skin photoaging and related inflammation. Its effects include inhibition of melanin production, wrinkle reduction, antioxidant and anti-inflammatory actions. This review primarily focuses on the specific signaling pathways involved in skin photoaging and the mechanisms by which curcumin mitigates photoaging. Key topics include the antioxidant and anti-inflammatory properties of curcumin, regulation of matrix metalloproteinase, regulation of autophagy and apoptosis, improvement of pigmentation, and regulation of microbial balance. Additionally, addressing the critical issue of curcumin’s low bioavailability, the review summarizes the latest advancements in curcumin formulation improvements. This article aims to provide a comprehensive overview of curcumin’s progress of skin photoaging research and offer evidence for its further clinical application in dermatological treatments. The review contributes to a deeper understanding of the potential molecular mechanisms of curcumin in combating photoaging and presents new insights for the development of curcumin-based anti-photoaging products.
... In recent decades, drug delivery systems have witnessed substantial advancements; however, major limitations continue to impede therapeutic success across various disease conditions. Traditional delivery approaches are often associated with poor bioavailability, limited target specificity, rapid systemic clearance, and undesirable side effects, all of which reduce therapeutic efficacy and increase toxicity (Danhier et al., 2010;Barenholz, 2012). These challenges are especially pronounced in the treatment of complex diseases such as cancer, neurodegenerative disorders, and autoimmune conditions, where systemic administration leads to off-target effects and drug resistance (Hossen et al., 2019). ...
Exosome-mediated drug delivery systems have emerged as a promising platform for
precision medicine, offering a natural and biocompatible means to deliver therapeutics
with high specificity. Exosomes are nanoscale vesicles secreted by various cell types,
such as mesenchymal stem cells, tumor cells, and immune cells, and are involved in
intercellular communication. Due to their unique properties, such as the ability to cross
biological barriers (e.g., the blood-brain barrier) and target specific tissues, exosomes
hold great potential for overcoming current drug delivery challenges, including poor
bioavailability, off-target effects, and toxicity. This review explores the biogenesis,
composition, and functional characteristics of exosomes, focusing on their advantages
... Liposomal formulation of doxorubicin, improves circulation half-life and tumor absorption while reducing toxicity. (Barenholz, 2012) Abraxane Formulation of albumin-bound paclitaxel nanoparticles for the treatment of breast cancer. (Fenton et al., 2018) There are four essential steps in drug delivery: ...
Biomaterials have attracted growing interest in the biomedical field thanks to their unique ability to interact with biological systems and make a significant contribution to advances in medicine, tissue engineering and sustainable technologies. Their importance lies in their dual potential: improving patients' quality of life while reducing their impact on the environment. This chapter first presents a detailed classification of biomaterials, distinguishing between natural, synthetic and hybrid categories. Next, the key properties of biomaterials are explored, showing their role in biocompatibility, durability and clinical performance. These fundamental characteristics directly influence the choice of biomaterials for a variety of applications. 52 In addition, this chapter highlights the diversity of current biomaterial applications, while discussing the persistent challenges and limitations encountered in their design and use. Finally, future prospects are discussed, including the emergence of personalized biomaterials, which could revolutionize biomedical technologies.
... Also, liposomal NPs have also been investigated for their ability to encapsulate imaging agents/drugs and facilitate prolonged circulation, as well as for improved biocompatibility. 55 Both liposomes and PLGA-NPs represent good possibilities for targeted imaging and/or therapy, and the choice of one or the other systems is strongly linked to the nature of drugs to be delivered, if mainly hydrophilic or hydrophobic. ...
... Several gene-associated human diseases have been treated and diagnosed with targeted nanocarriers over the last few decades. However, NPs remain a major health concern due to their toxicity and ability to accumulate in healthy tissues as evidenced by studies indicating induced inflammation, DNA damage, and cellular dysfunction 67,68 . Therefore, a critical need exists for further research to develop safe and effective nanocarriers for clinical applications. ...
In our study, we prepared Fe3O4 nanoparticles (NPs) using food waste extract of Mealworm (Tenebrio molitor) larvae fed spinach (Spinacia oleracea), which is rich in iron. A coating was applied to Fe3O4 NPs containing hyperbranched spermine-polyethylene glycol-folic acid (FHSPF) and spermine-polyethylene glycol-folic acid (FSMPF). Polymer was loaded with siRNA or DNA. DLS¹, H-NMR, FTIR, EDX, Zeta potential and TEM were used to analyze morphology of NPs. Biocompatibility, DNA release, and gene transfer properties were evaluated. Coats concentration in our NPs increased zeta potential, DNA release, encapsulation, and gene delivery efficiency. As determined by cell viability, our NPs exhibit low cytotoxicity and good compatibility; on the other hand, we evaluated their ability to transfer into MCF-7 cells using fluorescence microscopy and flow cytometry. According to this analysis, increasing DNA or siRNA concentration in NPs improved gene transfer efficiency. As a result of cytotoxicity assay, FHSPF2 NPs showed high biocompatibility; NPs were demonstrated to deliver siRNA-FAM to breast cancer cells and mice in vivo, and they were also rated excellent for delivering siRNA-FAM to the tumor site using external magnetic fields. Magnetic fields significantly cause NPs to adsorb at the tumor site.
... It enhances the delivery of the drug to targeted cells while minimizing side effects and improving therapeutic efficacy. [40,41] As interest in nanotechnology has grown, significant developments in NPs preparation have emerged, particularly through the use of diverse carrier systems. These advancements have improved the synthesis, stability, and functionality of NPs. ...
Recent advancements in medicinal chemistry have highlighted the potential of essential oils (EOs) due to their diverse bioactive constituents with anticancer properties. Despite their promising effects, the use of EOs as single treatments faces significant challenges, such as limited solubility and stability. To overcome these limitations, nanotechnology-based approaches have emerged as a viable solution. Nanocarriers can enhance drug delivery by optimizing the pharmacokinetics and pharmacodynamics of therapeutic agents, including EOs. Additionally, the combinatorial approach using multiple therapeutic agents is gaining recognition for its effectiveness in addressing drug-resistant cancer cells. Integrating EOs with conventional chemotherapeutic agents through nanotechnology offers a promising strategy to improve therapeutic outcomes. This review examines recent advances in nanotechnology for cancer therapy, focusing on the use of nanocarriers for the encapsulation and targeted delivery of EOs. It discusses the mechanisms behind the anticancer effects of EOs, including their antioxidant, anti-mutagenic, and anti-proliferative activities. Furthermore, the review explores how nanotechnology-based combination approaches can enhance therapeutic efficacy and address current challenges in cancer treatment.
... Doxil® (pegylated liposomal doxorubicin) was the first FDA-approved nanodrug for ovarian cancer and Kaposi's sarcoma. Pegylation increases circulation time, and liposomal encapsulation reduces cardiotoxicity [34] . Liposomes can be functionalized with ligands (e.g., folate, transferrin) to target cancer cell receptors overexpressed in specific tumors [35] . ...
Background: Recent advancements in biochemistry have significantly reshaped the landscape of cancer therapy. Traditional treatments like chemotherapy and radiotherapy, while effective, often lack specificity and induce systemic toxicity. In contrast, biochemical strategies aim to precisely target molecular mechanisms underlying tumor development and progression. Methods: This review aims to highlight the latest biochemical innovations in cancer treatment, focusing on their mechanisms, clinical potential, and associated challenges. A comprehensive analysis of recent peer-reviewed literature was conducted, covering topics such as targeted molecular inhibitors, enzyme-based therapies, gene editing technologies (e.g., CRISPR-Cas), RNA-based therapeutics, metabolic reprogramming, and nanotechnology-enhanced drug delivery systems. Results: Emerging biochemical modalities have shown promise in improving treatment specificity, minimizing adverse effects, and enhancing patient outcomes. Notably, CRISPR-mediated gene editing, siRNA-based silencing of oncogenes, and multifunctional nanoparticles for targeted drug delivery have opened new frontiers in precision oncology. Conclusion: Biochemical cancer therapies are transforming oncology into a more personalized and less invasive discipline. Although challenges such as tumor heterogeneity, delivery barriers, off-target effects, and cost remain, ongoing research and interdisciplinary integration hold great promise for future clinical success.
... Over the past 10 years, nanotechnology has advanced quickly, particularly in the area of medicine. Since the US Food and Drug Administration (FDA) approved Doxil®, a PEGylated liposomal doxorubicin, in 1995 as the first nanodrug, nanotechnology has attracted a lot of attention for the creation of innovative theranostic strategies [7]. Nanoparticles (NPs) in the 1-100 nm size range have gained recognition in recent years, particularly in the biomedical field, for their special applications. ...
Inflammatory diseases can occur due to many factors including environmental exposure, infection and as the part of immune response. However, the prolonged and dysregulated inflammation could be harmful. It could persist over time and hence it could damage a particular organ or a system. To manage the medical conditions developed during the inflammation, there is a need to make use of anti-inflammatory drugs. Many types of drugs are already available to prevent the organ-specific and system-specific damage. However, there are some limitations in the treatment. The target-specific therapy is the major challenge in delivering the anti-inflammatory drug at the anticipated site. To overcome this challenge, nanomaterials could be a better alternative. Nanomaterials have many advantages over other classical drug delivery agents, due to which they are preferred for the delivery of anti-inflammatory drugs for the treatment of inflammatory diseases. Hence, the present chapter is focused on a brief discussion of the treatment of inflammation, followed by a detailed discussion of the various nanomaterials that can be used as a delivery agent for drugs for the treatment of inflammation. Moreover, the nanotoxicity as the major challenge in the said therapy is also discussed with the various options to avoid the nanotoxic effects.
... Over the past 10 years, nanotechnology has advanced quickly, particularly in the area of medicine. Since the FDA (US Food and Drug Administration) approval of PEGylated liposomal doxorubicin (Doxil ® ) as the first nano-drug in 1995, nanotechnology has attracted a lot of attention for the creation of innovative theranostic strategies [10]. Nanoparticles (NPs) in the 1-100 nm size range have gained recognition in recent years, particularly in the biomedical field, for their special applications. ...
Inflammation is a natural reaction to pathogenic infections or tissue injury that helps restore homeostasis by protecting the host from external pathogens and healing damaged tissues. It has three phases: induction, pro-inflammatory, and resolution. Unchecked inflammation can lead to the development of many inflammatory diseases, including sepsis, obesity, cancer, and cardiovascular, neurological, and immunological diseases. Dysregulated localized or chronic inflammation can be caused by an imbalance between the immune system's innate and adaptive components. Anti-inflammatory drugs are critical for treating inflammatory diseases, but they have limitations such as poor tissue selectivity, systemic adverse effects, and inefficiency in overcoming biological barriers. Nanotechnology has grown quickly in medicine since the FDA-approved PEGylated liposomal doxorubicin (Doxil®) in 1995. Nanoparticles (NPs) in the 1–100 nm size range have received attention for their novel applications in biomedicine.
Computational simulations at the molecular level are crucial for advancing drug delivery systems by providing insights into drug-receptor interactions, permeation across biological barriers, solubility, stability and conformational changes. Techniques such as molecular modeling, molecular docking studies, molecular dynamics (MD) simulations, quantum mechanics/molecular mechanics (QM/MM) simulations, and free energy calculations play key roles. Molecular modeling predicts structures, conformations, and properties essential for drug efficacy. Docking studies forecast interactions and binding affinities, guiding lead optimization and toxicity assessment. MD simulations reveal drug behavior, stability, and interactions patterns. QM/MM simulations accurately model active sites and chemical reactions. Free energy calculations predict binding affinities and thermodynamic properties, enhancing our understanding of drug receptor interactions. These techniques optimize drug design, pharmacokinetics, and pharmacodynamics and targeted drug delivery systems. Visualization and analysis tools help interpret complex interactions, facilitating effective therapeutic interventions. Computational simulations span development stages, from design to clinical trial simulations, providing a robust frame work for safer and more effective pharmaceuticals. In-silico model accelerate drug discovery, reduce animal testing, address ethical concerns, and improve development pipeline efficacy.
Magnetic mesoporous silica nanoparticles (MMS NPs) stand out as excellent options for targeted chemotherapy owing to their remarkable features, such as extensive surface area, substantial pore volume, adjustable and uniform pore size, facile scalability, and versatile surface chemistry. This review comprehensively explores the latest developments in MMS NPs, emphasizing their design, functionalization, and application in cancer therapy. Initially, we discuss the critical need for targeted and controlled drug delivery (DD) in oncology, highlighting the role of magnetic and MMs in addressing some challenges. Subsequently, the key features of MMS NPs, such as their high surface area, pore structure, and functionalization strategies, are examined for their impact on their DD performance for efficient cancer chemotherapy. The integration of chemotherapy methods such as photothermal therapy and photodynamic therapy with MMS NPs is also explored, showcasing multifunctional platforms that combine imaging and therapeutic capabilities. Finally, we identify the current challenges and provide future perspectives for the development and clinical translation of MMS NPs, underscoring their potential to reshape CT paradigms.
Nanoparticles are one of the innovative drug delivery systems, particularly valuable for the targeted delivery of orphan drugs in rare diseases. Their nanoscale size and large surface area to volume ratio allow for enhanced interaction with biological systems, providing a platform for efficient drug loading and controlled release. Lipid-based nanoparticles, such as liposomes and solid lipid nanoparticles, offer biocompatibility and stability, ensuring sustained and targeted delivery with minimal toxicity. Polymeric nanoparticles, including dendrimers, enable the solubilization of hydrophobic drugs and precise control over drug release. Inorganic nanoparticles, like gold and silica nanoparticles, provide versatility in functionalization and targeted delivery, enhancing therapeutic efficacy. These systems significantly reduce systemic side effects and improve the therapeutic index of orphan drugs, the drugs that are used to treat the rare diseases. Their ability to protect drugs from degradation ensures stability and prolonged activity, making them particularly suitable for complex and chronic conditions associated with rare diseases. Overall, nanoparticle-based drug delivery systems represent a transformative approach in the treatment of rare diseases, offering precise, controlled, and safe delivery of therapeutics, thereby improving patient outcomes and quality of life.
The drug delivery systems have evolved significantly, driven by the goals of improving therapeutic efficacy, patient compliance, and minimizing adverse effects. Next-generation technologies offer promise in overcoming challenges associated with conventional methods, including limited bioavailability, poor solubility, and inadequate targeting. Controlled-release formulations have revolutionized treatment strategies since the 1950s, offering advantages such as precise drug release kinetics, improved solubility, and reduced toxicity. Integrating advancements in material science, nanotechnology, and biotechnology, modern systems aim to optimize drug release kinetics, enhance targeting efficiency, and minimize systemic toxicity. Active targeting and stimuli-responsive strategies further refine delivery precision, addressing off-target effects and upgrading therapeutic outcomes. Future advancements will focus on developing long-acting delivery technologies and integrating smart materials for stimuli-triggered release, aiming to achieve personalized therapeutic interventions. However, challenges such as scalability, regulatory compliance, and long-term safety profiles necessitate rigorous evaluation and interdisciplinary collaboration. This review explores recent advancements, discusses challenges, and outlines future directions in next-generation drug delivery systems, aiming to foster more effective, targeted, and patient-centric therapeutic interventions.
Precise and targeted delivery remains a significant challenge in the field of RNA therapeutics, essential for their successful clinical application. RNA molecules are inherently unstable in biological environments due to their susceptibility to degradation by RNases. To circumvent this challenge, RNA therapeutics require effective delivery systems that can protect and deliver the therapeutic RNA to its intended destination within cells. The development of innovative RNA delivery vehicles is therefore crucial. These vehicles serve multiple roles: shielding RNA from extracellular RNases, facilitating its cellular uptake, and promoting its release into the cytoplasm where it can undergo translation and produce therapeutic proteins. Various delivery strategies have been explored, including lipid nanoparticles, polymer-based carriers, viral vectors, and peptide-based complexes. Each approach offers distinct advantages in terms of stability, efficacy, and specificity in targeting different tissues or cell types. Recent advancements in RNA delivery technologies have focused on enhancing delivery efficiency, reducing immunogenicity, and improving tissue-specific targeting. Nanoparticle-based systems, for instance, can encapsulate RNA molecules, protecting them during transit through the bloodstream and enhancing their uptake by target cells through receptor-mediated endocytosis. Similarly, viral vectors engineered for RNA delivery can exploit natural mechanisms of cell entry, although concerns about safety and immune responses persist. Moreover, the ability to precisely engineer delivery systems allows for the customization of RNA therapeutics tailored to specific diseases or patient populations. This personalized approach holds promise for treating a wide range of disorders, from genetic diseases to cancers, by delivering therapeutic RNA directly to affected tissues while minimizing off-target effects. The ongoing advancements in RNA delivery systems are paving the way for the clinical translation of RNA therapeutics. By addressing the challenges of stability, delivery efficiency, and specificity, these innovations promise to unlock the full potential of RNA-based therapies in improving patient outcomes and advancing personalized medicine.
Breast cancer (BCa) remains a significant health challenge worldwide, with a high propensity for early metastasis and poor prognosis. While surgery, chemotherapy, and radiotherapy are fundamental for managing BCa, severe side effects, such as low patient adherence and suboptimal survival outcomes, cause concern. Therefore, there is a critical need to innovate new approaches that facilitate early detection, accurate diagnosis, and more effective treatment strategies for BCa. Nanotechnological approaches have been introduced for the diagnosis and treatment of various cancers, especially BCa. The current review aims to emphasize and highlight possible applications of nanomedicine in early detection, accurate diagnosis and efficient treatment strategies for BCa. Nanocarriers can deliver chemotherapeutic agents, enhancing cytotoxicity against BCa cells and preventing the development of drug resistance. Nanoparticles also boost the efficacy of gene therapy which promotes their potential for regulating gene expression. The co‐delivery of drugs and genes by nanoparticles can have a synergistic effect on BCa and remodel the tumor microenvironment. In this review, we discussed the latest advances in the application of nanomedicines for diagnosing and treating BCa. Current research highlights the potential benefits of nanomedicine over traditional approaches and further efforts to translate these research findings into clinical practice for BCa.
Cell membrane coating (CMC) of nanoparticles (NPs) has emerged as a prominent strategy that has gained significant attention and achieved notable progress across various therapeutic sectors. Coating NPs with natural cell membranes endows them with various functions and addresses various challenges in drug delivery, such as prolonging circulation time, reducing immunogenicity, and improving targeting efficiency and cellular communication. Among the different NPs, lipid nanoparticles (LNPs) have revolutionized the field of nanomedicine by providing various advantageous features for drug delivery. The versatile characteristics of LNPs synergize well with cell membranes’ biomimetic properties, creating hybrid structures with enhanced functionalities for diverse biomedical applications. A more advanced form of LNPs with significantly enhanced capabilities can be achieved through CMC. However, significant opportunities remain for further advancements, with ongoing efforts focused on discovering innovative applications and fully harnessing the potential of this promising combination. This article provides a critical review of recent progress in cell membrane coated‐LNPs (CMC‐LNPs). First, different LNP types, their preparation methods, and coating strategies are summarized. The development, properties, functions, and applications of CMC‐LNPs are then discussed. Last, their advantages, limitations, challenges, and future perspectives are presented.
The efficacy of adoptive T cell therapy (ACT) against solid tumors is significantly limited by the immunosuppressive tumor microenvironment (TME). Systemic administration of immunostimulants provides inadequate support to ACT cells and often elicits systemic toxicities. Here we present cell‐surface‐anchored nucleic acid therapeutics (NATs) to robustly enhance ACT through synergistic blockade of immunosuppressive adenosine and PD‐1/PD‐L1 pathways in tumors. Two distinct NATs‐DNA aptamers targeting PD‐L1 (aptPD‐L1) and ATP (aptATP)‐are engineered to form partially‐hybridized duplexes (aptDual) that can efficiently anchor to cell surface before transfer. Backpacked aptDual spatial‐temporally co‐localize with ACT cells in vivo and jointly infiltrate the ATP‐rich TME. Upon binding with ATP, aptDual dissociates to responsively release aptPD‐L1. Concurrently, aptATP scavenges extracellular ATP and its metabolite adenosine to disrupt the inhibitory adenosinergic axis, thereby sensitizing ACT cells to immune checkpoint blockade by aptPD‐L1. This dual inhibition elicited a remarkable 40‐fold increase in functional tumor‐infiltrating ACT cells, substantially boosting the efficacy of TCR‐T and CAR‐T cells in multiple solid tumor models, even in immunologically “cold” tumors. NAT backpacks provide a facile, versatile, and safe strategy to augment various ACTs against solid tumors.
Immunostimulants can be highly effective anti-cancer therapeutics; however, their systemic use is often limited by adverse reactions (AEs). Formulating immunostimulants into nanoparticle systems can potentially alleviate these, but nanoparticle design is key. In previous studies, we encountered anti-nanoparticle reactions with systemically administered PEGylated liposomes containing Toll-like receptor (TLR) agonists. In this work, we hypothesized that using a micellar drug delivery platform, rather than a liposomal platform, could retain the benefits of nanoparticle delivery systems while avoiding PEG recognition and generation of anti-PEG antibodies. Indeed, micellar formulation of the TLR7 agonist 1V270 induced far lower anti-PEG antibody levels and was well tolerated while retaining a similar circulation profile across multiple dosing. Furthermore, 1V270-micelles showed strong efficacy as monotherapy in murine syngeneic cancer models and showed combinatorial efficacy with anti-PD1 treatment. Following intravenous administration, tumors developed an inflammatory reaction and macroscopic hemorrhage 6 h post treatment followed by significant cell death 24 h post treatment, which was not observed in spleens and livers. Tumors displayed strong innate signaling within 24 h, which was accompanied by persistent massive infiltration of neutrophils and antigen-specific cytotoxic T cells, reduction in cancer cells and broad upregulation of immune-related genes. 1V270-micelles were well tolerated by non-human primates at doses equivalent to those displaying therapeutic activity in murine cancer models. Overall, the study provides novel insights into the mode of action of TLR7 agonists and demonstrates good and sustained tolerability of 1V270-micelles across animal models and excellent efficacy in murine cancer models by bridging innate and adaptive immunity.
The poor therapeutic outcomes and important side effects caused by certain conventional drug therapies have led the researcher to implement a new way to improve the outcomes in the management of certain health conditions, especially cancer, cardiovascular disease, brain disease, respiratory disorders, genetic disorders, etc. Nanotechnology has revolutionized medicine. The introduction of nano-object-like drugs or carriers has shown promising outcomes in the management of diseases. Their engineering employs various types of technology; their medical uses can involve targeting drug delivery systems, controlling drug release, and improving existing drug solubility; and their therapeutic effects include good bioavailability and fewer side effects. There are many nanodrugs available on the market, each with well-defined characteristics, structures, and pharmacological effects on the body, as well as a level of toxicity. This book chapter aims to provide an overview of the recent nanodrugs developed and approved by FDA-EMA regulatory agencies highlighting their pharmacology, their advantages over the existing drugs, and the room for improvement.
As survival rates for cancer patients improve due to advancements in treatment modalities, there is an increasing prevalence of cardiovascular complications, necessitating a comprehensive understanding of this intersection. This review aims to elucidate the intricate relationship between cancer and cardiovascular disease, highlighting the growing concern of cardiovascular toxicity associated with cancer therapies. It explores various cancer treatments, including chemotherapy, targeted therapies, and radiation, and their associated cardiovascular risks, such as heart failure and ischemic heart disease. In addition, it discusses the importance of proactive cardiovascular risk assessments and ongoing monitoring in cancer patients to mitigate adverse outcomes. Strategies for prevention and management, including lifestyle modifications and pharmacologic interventions, are also examined to support the cardiovascular health of cancer survivors. Unlike previous reviews, this work integrates insights from multidisciplinary collaborations, emphasizing underexplored mechanisms of cardiovascular toxicity and the role of innovative monitoring tools. It also highlights emerging therapeutic strategies tailored to mitigate these risks, providing a forward-looking perspective in this critical area of research. The need for a collaborative method that includes oncologists, cardiologists, and primary care providers is emphasized to ensure integrated care that addresses both cancer treatment and cardiovascular health. This review serves as a critical resource for healthcare professionals seeking to improve the long-term outcomes for cancer survivors by recognizing and managing cardiovascular risks.
Doxorubicin (DOX) is one of the most powerful chemotherapy drugs used to treat different kinds of cancer. However, its usage has been limited by typical side effects and drug resistance, particularly cardiotoxicity. According to studies, a more effective and promising method is to conjugate it or entrap it in biocompatible nanoparticles. Compared to free DOX and traditional formulations, nanoparticles using specific processes or techniques can improve drug stability, minimize premature release at untargeted locations, and lower systemic toxicity. This review explains how various nanocarriers target the tumor to improve therapeutic efficacy while reducing the negative effects of DOX.
Advances in nanotechnology have paved the way for innovative drug delivery systems that enhance the effectiveness of cancer treatment. Cancer cell membrane‐based nanoparticles (CCM‐NPs) and cancer cell‐derived small extracellular vesicles (CsEVs) are emerging as promising drug delivery systems for cancer treatment due to their inherent properties such as low immunogenicity and natural targeting capabilities to cancer cells. However, a comprehensive comparison of the advantages, disadvantages, and similarities of these two platforms is lacking. This review summarizes the natural, engineered, and hybrid forms of CCM‐NPs and CsEVs‐based drug delivery platforms with a focus on comparison of these two platforms, considering key aspects including preparation methods, drug encapsulation strategies, delivery pathways, immune evasion, targeting ability, and their potential for clinical applications. By understanding the strengths and weaknesses of each approach, the aim is to pave the way for next‐generation nanoscale drug delivery platforms and contribute to the development of more effective and personalized cancer therapies.
Although cancer chemopreventive agents have been confirmed to effectively protect high-risk populations from cancer invasion or recurrence, only over ten drugs have been approved by the U.S. Food and Drug Administration. Therefore, screening potent cancer chemopreventive agents is crucial to reduce the constantly increasing incidence and mortality rate of cancer. Considering the lengthy prevention process, an ideal chemopreventive agent should be nontoxic, inexpensive, and oral. Natural compounds have become a natural treasure reservoir for cancer chemoprevention because of their superior ease of availability, cost-effectiveness, and safety. The benefits of natural compounds as chemopreventive agents in cancer prevention have been confirmed in various studies. In light of this, the present review is intended to fully delineate the entire scope of cancer chemoprevention, and primarily focuses on various aspects of cancer chemoprevention based on natural compounds, specifically focusing on the mechanism of action of natural compounds in cancer prevention, and discussing in detail how they exert cancer prevention effects by affecting classical signaling pathways, immune checkpoints, and gut microbiome. We also introduce novel cancer chemoprevention strategies and summarize the role of natural compounds in improving chemotherapy regimens. Furthermore, we describe strategies for discovering anticancer compounds with low abundance and high activity, revealing the broad prospects of natural compounds in drug discovery for cancer chemoprevention. Moreover, we associate cancer chemoprevention with precision medicine, and discuss the challenges encountered in cancer chemoprevention. Finally, we emphasize the transformative potential of natural compounds in advancing the field of cancer chemoprevention and their ability to introduce more effective and less toxic preventive options for oncology.
In situ vaccination (ISV) has emerged as a promising strategy in cancer immunotherapy, offering a targeted approach that uses the tumor microenvironment (TME) to stimulate an immune response directly at the tumor site. This method minimizes systemic exposure while maintaining therapeutic efficacy and enhancing safety. Recent advances in nanotechnology have enabled new approaches to ISV by utilizing nanomaterials with unique properties, including enhanced permeability, retention, and controlled drug release. ISV employing nanomaterials can induce immunogenic cell death and reverse the immunosuppressive and hypoxic TME, thereby converting a “cold” tumor into a “hot” tumor and facilitating a more robust immune response. This review examines the mechanisms through which nanomaterials-based ISV enhances anti-tumor immunity, summarizes clinical applications of these strategies, and evaluates its capacity to serve as a neoadjuvant therapy for eliminating micrometastases in early-stage cancer patients. Challenges associated with the clinical translation of nanomaterials-based ISV, including nanomaterial metabolism, optimization of treatment protocols, and integration with other therapies such as radiotherapy, chemotherapy, and photothermal therapy, are also discussed. Advances in nanotechnology and immunotherapy continue to expand the possible applications of ISV, potentially leading to improved outcomes across a broad range of cancer types.
Ultrasound is used in many medical applications, such as imaging, blood flow analysis, dentistry, liposuction, tumor and fibroid ablation, and kidney stone disruption. In the past, low frequency ultrasound (LFUS) was the main method to downsize multilamellar (micron range) vesicles into small (nano scale) unilamellar vesicles. Recently, the ability of ultrasound to induce localized and controlled drug release from liposomes, utilizing thermal and/or mechanical effects, has been shown. This review, deals with the interaction of ultrasound with liposomes, focusing mainly on the mechanical mechanism of drug release from liposomes using LFUS. The effects of liposome lipid composition and physicochemical properties, on one hand, and of LFUS parameters, on the other, on liposomal drug release, are addressed. Acoustic cavitation, in which gas bubbles oscillate and collapse in the medium, thereby introducing intense mechanical strains, increases release substantially. We suggest that the mechanism of release may involve formation and collapse of small gas nuclei in the hydrophobic region of the lipid bilayer during exposure to LFUS, thereby inducing the formation of transient pores through which drugs are released. Introducing PEG-lipopolymers to the liposome bilayer enhances responsivity to LFUS, most likely due to absorption of ultrasonic energy by the highly hydrated PEG headgroups. The presence of amphiphiles, such as phospholipids with unsaturated acyl chains, which destabilize the lipid bilayer, also increases liposome susceptibility to LFUS. Application of these principles to design highly LFUS-responsive liposomes is discussed.
The ability of low frequency ultrasound (LFUS) to trigger the release of drugs from nano sterically stabilized liposomes (nSSL) in vitro, without affecting the drugs' chemical integrity or biological potency, has been previously shown. Herein, the ability of LFUS to (a) trigger the release of cisplatin from nSSL in vivo, and (b) affect the therapeutic efficacy by locally releasing the drug, was studied. For this, nSSL loaded with the anti-cancer chemotherapeutic agent cisplatin were injected intraperitoneally (i.p.) to mice bearing well-developed J6456 murine lymphoma tumors in their peritoneal cavity. Then, LFUS was applied externally to the abdominal wall for 120 s, and drug release was quantified. Nearly 70% of the liposomal cisplatin was released in tumors exposed to LFUS, compared to <3% in those not exposed to LFUS. The effect of LFUS-induced localized drug release on the therapeutic efficacy was tested on BALB/c mice with C26 colon adenocarcinoma tumors in a footpad. Mice were injected intravenously with nSSL cisplatin, and 24 h later, the tumor was exposed to LFUS. The group treated by liposomal cisplatin combined with LFUS, compared to all other groups (i.e., free cisplatin with or without LFUS, or liposomal cisplatin without LFUS, or LFUS alone, or no treatment) had the best therapeutic score; tumors stopped proliferating and then regressed over time. This work presents a modality for the release of drugs from liposomes in vivo using LFUS. Implications of these findings for clinical applications of LFUS-induced liposomal drug release are discussed.
Liposomes were prepared with pH gradients across their membranes (acidic interiors with respect to the external buffer). These liposomes efficiently concentrated several catecholamines (dopamine, norepinephrine, and epinephrine) added to the external buffer. Our observations support a mechanism which suggests that pH gradients may contribute to uptake of catecholamines by sub-cellular storage sites.
Methoxypolyethylene glycols of 1900 daltons (PEG-1900) or 5000 daltons (PEG-5000) were covalently attached to bovine liver catalase using 2,4,6-trichloro-s-triazine as the coupling agent. Rabbits were immunized by the intravenous and intramuscular routes with catalase modified by covalent attachment of PEG-1900 to 43% of the amino groups (PEG-1900-catalase). The intravenous antiserum did not yield detectable antibodies against PEG-1900-catalase or native catalase, as determined by Ouchterlony and complement fixation methods, whereas the intramuscular antiserum contained antibodies to both PEG-1900-catalase and catalase. PEG-1900 did not react with either antiserum. Catalase was prepared in which PEG-5000 was attached to 40% of the amino groups (PEG-5000-catalase). This catalase preparation did not react with either antiserum. PEG-1900-catalase retained 93% of its enzymatic activity; PEG-5000-catalase retained 95%. PEG-5000-catalase resisted digestion by trypsin, chymotrypsin, and a protease from Streptomyces griseus. PEG-1900-catalase and PEG-5000-catalase exhibited enhanced circulating lives in the blood of acatalasemic mice during repetitive intravenous injections. No evidence was seen of an immune response to injections of the modified enzymes. Mice injected repetitively with PEG-5000-catalase remained immune competent for unmodieied catalase, and no evidence of tissue or organ damage was seen.
Purpose:
To compare the efficacy and safety of pegylated liposomal doxorubicin (PLD) and topotecan in patients with epithelial ovarian carcinoma that recurred after or didn't respond to first-line, platinum-based chemotherapy.
Patients and methods:
Patients with measurable and assessable disease were randomized to receive either PLD 50 mg/m(2) as a 1-hour infusion every 4 weeks or topotecan 1.5 mg/m(2)/d for 5 consecutive days every 3 weeks. Patients were stratified prospectively for platinum sensitivity and for the presence or absence of bulky disease.
Results:
A total of 474 patients were treated (239 PLD and 235 topotecan). They comprised the intent-to-treat population. The overall progression-free survival rates were similar between the two arms (P =.095). The overall response rates for PLD and topotecan were 19.7% and 17.0%, respectively (P =.390). Median overall survival times were 60 weeks for PLD and 56.7 weeks for topotecan. Data analyzed in platinum-sensitive patients demonstrated a statistically significant benefit from PLD for progression-free survival (P =.037), with medians of 28.9 for PLD versus 23.3 weeks for topotecan. For overall survival, PLD was significantly superior to topotecan (P =.008), with a median of 108 weeks versus 71.1 weeks. The platinum-refractory subgroup demonstrated a nonstatistically significant survival trend in favor of topotecan (P =.455). Severe hematologic toxicity was more common with topotecan and was more likely to be associated with dosage modification, or growth factor or blood product utilization.
Conclusion:
The comparable efficacy, favorable safety profile, and convenient dosing support the role of PLD as a valuable treatment option in this patient population.
In this report we describe the design of adriamycin (ADM)-containing liposome preparations aiming at optimization of various pre-established parameters. Regarding liposome composition phosphatidylserine (PS) and phosphatidylglycerol (PG) appear to be suitable negatively charged phospholipids which combined with phosphatidylcholine (PC) and cholesterol (CHOL), confer to liposomes high loading capacity for ADM and reasonable stability in plasma. Intravenous administration of these negatively-charged liposomes resulted in a favorable tissue distribution of ADM in both normal and tumor-bearing mice, characterized by decreased cardiac uptake of drug, and increased and sustained drug levels in the liver. Moreover, enhanced accumulation of drug also occurred in metastatic tumor cells isolated from the liver when ADM was injected in the liposome-associated form. This passive drug targeting resulted in an improved therapeutic efficiency of liposome-associated ADM in a tumor model of liver metastases. Liposome delivery of ADM was also shown to increase significantly its cytoreductive effect on spleen-infiltrating leukemia cells and to maintain the same cytoreductive efficiency on bone marrow residing leukemia cells with an overall favorable effect on survival in the BCL1 leukemia model. The reduction of ADM toxicity by liposome association together with the anti-tumor results indicate that liposomes represent a useful drug-delivery system for the treatment of major neoplastic conditions.
Doxorubicin in liposomes (abbreviated and registered as Doxil) is an anticancer nano-drug. Doxil is based on three unrelated principles: (i) using sterically stabilized liposomes, steric stabilization being achieved by the presence of pegylated distearoyl phosphat-idylethanolamine (2000Da PEG-DSPE), which results in long blood circulation time of the liposomes; (ii) high and stable remote loading of doxorubicin driven by a transmembrane ammonium sulfate gradient, which also allows for drug release at the tumor; and (iii) having the liposome lipid bilayer in the "liquid ordered" phase based on the high-Tm(53°C) hydrogenated soy phosphatidylcholine, and on cholesterol. In order to take advantage of the enhanced permeability and retention (EPR) efect and to achieve passive targeting of the liposomes into the tumor, the liposomes are nano-scale. This chapter describes the downs and ups of pre-Doxil and Doxil formulations, and how the lessons learned from the failure of pre-Doxil liposomal doxorubicin formulations were turned into the Doxil success. It demonstrates that such a development requires a multidisciplinary approach and is highly dependent on understanding and optimal use of physicochemical and nano-technology principles. Doxil, which is considered today the gold standard in liposome-based drug delivery systems, has opened the road to the development of other anticancer and anti-inflammatory nano-drugs that make used of the EPR efect and remote drug loading. © 2012 by Pan Stanford Publishing Pte. Ltd. All rights reserved.
This paper describes the parameters recommended for rational design of amphiphile-based drug carriers. The main advantage of a carrier is its ability to modify the pharmacokinetics and biodistribution of the drug, so that the drug level at the target is sufficient for therapeutic benefits. Three parameters are described. Two of them, the drug-to-carrier partition coefficient (KyiC) and the rate of drug release from the carrier (kff), are related to drug-carrier interactions; the third one is the rate of carrier clearance (kc). We demonstrate that carrier performance for drugs associated with the carrier amphiphile(s) is determined to a large extent by Kc, while for drugs encapsulated in the aqueous phase of the carrier it is important that koff will be similar to kc These conclusions are based on two examples: (i) Amphotericin B as a drug associated with five dosage forms which represent different types of amphiphile-based carriers: micelles (Fungizone), stable micelle-like disks (Amphocil), a complex with phospholipids (ABPLC), liposomes (AmBisome), and a submicronized emulsion, (ii) Liposomal doxorubicin which consisted of either doxorubicin associated with the membrane of negatively-charged, fluid oligolamellar liposomes (L-DOX) or doxorubicin loaded by an ammonium sulfate gradient into small, unilamellar, rigid liposomes having steric stabilizing lipid grafted in their lipid bilayer, (S-DOX). To better understand what contributes to k, we also describe the effect of bilayer acyl chain composition and the role of precipitation of the drug inside the liposomes.
In an attempt to enhance the therapeutic efficacy of interleukin-2 (IL-2), recombinant human IL-2 was encapsulated either in large conventional liposomes or in small (mean diameter 65 nm), unilamellar, long-circulating, extravasating liposomes [referred to as sterically stabilized liposomes (SSLs)]. The SSL-IL-2 activity was assessed in vitro and in mice in comparison with soluble IL-2, IL-2 in conventional liposomes (non-SSL-IL-2), and pegilated IL-2 (PEG-IL-2). The main observations were as follows: (a) SSLs were far better carriers than conventional liposomes with regard to encapsulation efficiency and pharmacokinetics; (b) > 85% of IL-2 biological activity was consistently encapsulated in SSLs; (c) SSL-IL-2 was much more stable than soluble IL-2 at 4 and 37 degrees C; (d) SSL-IL-2, but not ''empty'' liposomes, bound in vitro to IL-2 receptor-bearing T-cells, indicating that the domain of the cytokine molecule involved in binding to the receptor is exposed on the outer liposome membrane; (e) release of IL-2 from the liposomes was not required for its in vitro biological activity; (f) plasma half-lives (t1/2 alpha, t1/2 beta) and area under the curve (AUC) of SSL-IL-2 were 10-30 times greater than those of soluble IL-2 and similar to those of PEG-IL-2; and (g) IL-2 is released from the SSLs in vivo with a t1/2 of similar to 40 min, although the SSL-IL-2s retained their steric stabilization in the plasma for > 4 h, with little liposome accumulation in the reticuloendothelial system. These data, together with the improved immunomodulatory and antitumor activity of SSL-IL-2 in mice, suggest that SSL-IL-2 might be a therapeutic agent superior to soluble IL-2.
The role of the membrane hydration layer in preventing membrane
oxidative damage has been evaluated by comparing bilayers with and
without an extended hydration layer. The extended hydration layer was
obtained through the use of a novel phospholipid in which polyethylene
glycol of 2000 Da molecular mass (PEG2000) was covalently
attached to the phosphate headgroup of a phospholipid backbone to form
dihexadecylphosphatidyl
PEG2000—α-{[2,3-bis(hexadecyloxy)propoxy](h
ydroxyphosphinoyl}-ω-methoxypoly(oxyethane-1,2-diyl)
monosodium salt. The amount of water bound to free PEG and to the
DHP-PEG2000 was determined by differential scanning
calorimetry. Small unilamellar liposomes composed of egg
phosphatidylcholine and DHP-PEG2000 were prepared. 44% of the
phospholipid contained one polyunsaturated acyl chain. Oxidative damage
to liposomes after exposure to three different oxidation procedures was
measured by the disappearance of polyunsaturated acyl chains, as
determined by GC. Oxidation procedures used were: (i)
exposure to ionizing γ-irradiation (9200 Gy), for which the
grafted PEG2000 provided significant protection against
oxidation, with minimal damage to the PEG2000 as determined
by 1H NMR and TLC. (ii) Storage for 6 months
at 4 °C or for 4 months at 4 °C followed by 4 d at
37 °C, for which the presence of
DHP-PEG2000retarded acyl chain peroxidation.
(iii) Oxidation of the liposomes by
2,2′-azo(2-amidinopropane) dihydrochloride (a positively charged
water-soluble peroxyl radical initiator), for which there was no
protection by DHP-PEG2000 (probably due to electrostatic
binding of the AAPH to the negatively charged membranes, thereby
overriding the hydration layer protection
barrier).
Abstract The amphipathic anthracycline base doxorubicin (DXR) was accumulated in the aqueous phase of the liposomes where it reached a level as high as 100-fold its concentration in the remote loading medium. Most of the intraliposomal DXR was present in an aggregated state. Efficient (>90%) and stable loading into the liposomes' and ligandoliposomes' aqueous phase was obtained by using gradients of ammonium sulfate in which the ammonium sulfate concentration in the liposomes was higher than its concentration in the extraliposomal medium [(NH4)2SO4)lip. [(NH4)2SO4)med.]. The “remote” loading is a result of the DXR exchange with ammonia from (NH4)2SO4. Both the ammonium and sulfate contribute to high level and stability of the loading. The ammonium sulfate gradient method differs from most other chemical approaches used for remote loading of liposomes since it neither requires to prepare the liposomes in acidic pH, nor to alkalinize the extraliposomal aqueous phase. Although most of the intraliposomal DXR is present in an aggregated gel-like state, the drug is bioavailable. This approach permits the preparation of DXR-loaded liposomes of a broad spectrum of types, sizes, and composition, including sterically-stabilized liposomes, immunoliposomes, and sterically-stabilized immunoliposomes. Due to the long shelf stability (>6 mo), no “bedside” remote loading is required immediately before patient treatment, and the formulation is ready for injection. The stable encapsulation of the doxorubicin in an aggregated form also permits freezing and lyophilization of the liposomes with only minimal drug release. The loading by ammonium sulfate gradient approach meets all pharmaceutical requirements; it has brought the clinical use of DXR-loaded sterically-stabilized liposomes to reality.
Introduction Lipid Analysis and Purity Characterization and Preparation of Liposomes Stability and Preservation Liposome Engineering: A User Guide List of Abbreviations
Differential scanning calorimetry (DSC) measures the temperature-dependence of the excess heat capacity of a system due to thermal phase transitions. Heat capacity curves of liposomes that undergo such transitions contain information on the enthalpy and entropy of these transitions. Being sensitive to both the chemical composition of these liposomes and their physical state (especially size), DSC can serve as a powerful tool for quality control of liposomes. If calorimetric criteria are appropriately established using a proper reference lipid sample, the quality and stability of a liposomal preparation which has a distinct thermogram can be assessed by DSC.
Our laboratories have been working together in close collaboration for over 10 years concerning the design and performance of lipid-based drug delivery systems. Over the past 3 years we have conceived of, developed, and tested pre-clinically, a new liposome-based temperature-sensitive drug delivery system for the treatment of solid tumors. This work is reported in a series of four publications: ‘J. Liposome Res. 9 (1999) 491; Cancer Res. Adv. Brief 60(5) (2000) 1197; Cancer Res. 6(9) (2000) 748; and Cancer Res. 60 (2000) 6950’. Following a brief introduction concerning the motivations behind the work, this article will review these studies, including some of our earlier work that led to these ideas, and will present the rational design of the new liposome formulation from a materials engineering perspective.
Liposomes are now in the marketplace as cosmeticeuticals and, more important, pharmaceuticals. Three major achievements of liposome application: steric stabilization, remote loading of drugs by pH and ion gradients, and lipoplexes based on complexes of cationic liposomes with anionic nucleic acids or proteins extended research toward liposome application and opened the way for development of a large spectrum of products. However, liposomology still faces major deficiencies including: lack of control over drug release rate; sufficient loading of drugs for which pH and ion gradients do not apply; lack of means to override biological barriers (i.e. skin, blood–brain barrier); therapeutically efficient active targeting; and for a broad spectrum of non-medical applications, cheaper suitable raw materials (lipids). Overcoming these deficiencies is the current challenge of research and development of liposome application.
Large unilamellar vesicles (120–160 nm) composed of egg phosphatidylcholine (egg PC) containing approximately 22 wt% of polyunsaturated fatty acids (PUFA) and various mol% (0, 10, 22, or 45) of cholesterol were exposed to oxidative stress. The hydrophilic azo compound 2,2′-azobis-(2-amidinopropane)2HCl (AAPH) which was thermally decomposed to produce a constant flux of peroxy radicals was the source of the oxidative stress (≤48 h incubation at 37°C). Cholesterol loss following the oxidation was up to 33%, while PUFA were more extensively damaged; loss was up to 52, 88, and 100% for C–18:2, C–20:4, and C–22:6, respectively. (ii) Oxidizability of cholesterol when quantified in absolute amount was three-fold higher when its level was 45 mol%. The interrelationship between bilayer structure, especially its lateral organization and free volume, and lipid peroxidation are discussed. Differential scanning calorimetry of oxidized multilamellar vesicles lacking cholesterol revealed that a high level of oxidative damage to egg phosphatidylcholine PUFA resulted in the loss of the gel to liquid-crystalline phase transition of egg PC (broad peak at around −8°C).
Gradients of ammonium sulfate in liposomes [(NH4)2SO4]lip.>[(NH4)2SO4]med. were used to obtain ‘active’ loading of amphipathic weak bases into the aqueous compartment of liposomes. The loading is a result of the base exchange with the ammonium ions. This approach was applied to encapsulate anthracyclines and acridine orange inside the liposomes at very high efficiency (>90%). Doxorubicin was accumulated in the aqueous phase of the liposomes where it reached a level as high as 100-fold the doxorubicin concentration in the remote loading medium. Most of the intraliposomal doxorubicin was present in an aggregated state. The active entrapment and loading stability were dependent on liposome lipid composition, lipid quality, medium composition and temperature, as well as on the pKa and hydrophobicity of the base. The ammonium sulfate gradient approach differs from most other chemical approaches used for remote loading of liposomes, since it neither requires preparation of the liposomes in acidic pH, nor to alkalinize the extraliposomal aqueous phase. The stability of the ammonium ion gradient is related to the low permeability of its counterion, the sulfate, which also stabilizes anthracycline accumulation for prolonged storage periods (>6 months) due to the aggregation and gelation of anthracycline sulfate salt.
New lipidic carriers suitable for the sustained drug release in vivo are presented. They consist of middle sized, compact phospholipid vesicles with one or up to few lipid bilayers which are sterically stabilized with a small amount of large-head phospholipids. As an example, phosphatidylcholine (PC) liposomes casted with up to 10 mol% of phosphatidylethanolamine with a covalently attached polyethyleneglycol 5000 headgroup (PE-PEG) are discussed. Such vesicles exhibit a very long circulation time after an i.v. administration in mice; the improvement over pure phosphatidylcholine liposomes within the first 24 h exceeds 8000%, at this point nearly 25% of the applied PE-PEG liposomes being still in the circulation. This advantage is a consequence of reduced phagocytosis of the lipidic carriers, as shown by an in vitro assay with blood monocyte cells in the flow cytometric experiments. For example, after 6 h incubation with THP-1 monocyte cells in human plasma the difference between the uptake of standard distearoylphosphatidylcholine (DSPC) and novel liposomes containing 10% distearoylphosphatidylethanolamine-PEG is by 1000%. Vesicles with 2.5 mol% DSPE-PEG are also taken-up via phagocytosis relatively slowly. But the latter vesicles, moreover, retain most of the enclosed model-drug carboxyfluorescein after an incubation in plasma. The rate of permeation of the encapsulated substance from such DSPE-PEG liposomes is below 2.4% per h. This is by approximately a factor of two less than for pure DSPC liposomes; vesicles with a higher PE-PEG content are inferior in this respect. Long circulation time and high retention of the newly developed liposomes open up ways for the future systemic use as such stabilized drug carriers for the therapeutic applications in vivo.
There is a compelling need for an ultralong-acting local anesthetic. Previously, we demonstrated in mice and humans that encapsulation of bupivacaine into large multivesicular liposomes (Bupisome) prolongs drug residence time and analgesic duration at the injection site while reducing peak plasma concentration. However, we observed considerable leakage of bupivacaine from the liposomes during storage at 4 °C. This deficiency was overcome by modifying the lipid composition of Bupisome and by entrapping them in a Ca-alginate cross-linked hydrogel (Bupigel), forming stable, soft, injectable (3-5 mm) beads. Bupisome are not released from Bupigel, but their encapsulated bupivacaine is released into the bulk solution. Adding 0.5% to 2.0% free bupivacaine to the Bupigel prevented net loss of bupivacaine from the Bupisome after storage at 4 °C for 2 years, and at 37 °C enough bupivacaine was released to prolong analgesia. For injection subcutaneously into mice, the beads are drawn into a syringe, leaving the small amount of free bupivacaine behind. Both Bupisome and Bupigel formulations significantly prolonged analgesia in mice compared to standard bupivacaine, with Bupigel performing better than Bupisome.
We have previously shown that intravenous (i.v.) treatment with sterically stabilized nano-liposomes (NSSL) actively remote-loaded with the glucocorticoid (GC) methylprednisolone hemisuccinate (NSSL-MPS) or betamethasone hemisuccinate (NSSL-BMS) significantly decreased severity of adjuvant arthritis in Lewis rats (a model of human rheumatoid arthritis) throughout all disease stages. Here, we compared i.v. or subcutaneous (s.c.) weekly treatment with each of the two NSSL-GC to weekly or daily treatment with the free drugs or with the TNF-α antagonists Infliximab and Etanercept. Therapeutic efficacy and effects on the profile of pro-inflammatory (IL-6, TNF-α, and INF-γ) and anti-inflammatory (IL-10 and TGF-β) cytokines in rat sera and splenocyte tissue culture supernatants were compared to those of the liposomal and free drugs. Both s.c. and i.v. NSSL-GC suppressed arthritis significantly, compared to higher doses of the free drugs or to TNF-α antagonists. NSSL-GC also suppressed the secretion of pro-inflammatory cytokines, but did not change the levels of TGF- β. The highly efficacious anti-inflammatory therapeutic feature of these nano-drugs makes them candidates for treatment of human rheumatoid arthritis.
Remote loading of liposomes by trans-membrane gradients is used to achieve therapeutically efficacious intra-liposome concentrations of drugs. We have developed Quantitative Structure Property Relationship (QSPR) models of remote liposome loading for a data set including 60 drugs studied in 366 loading experiments internally or elsewhere. Both experimental conditions and computed chemical descriptors were employed as independent variables to predict the initial drug/lipid ratio (D/L) required to achieve high loading efficiency. Both binary (to distinguish high vs. low initial D/L) and continuous (to predict real D/L values) models were generated using advanced machine learning approaches and 5-fold external validation. The external prediction accuracy for binary models was as high as 91-96%; for continuous models the mean coefficient R(2) for regression between predicted versus observed values was 0.76-0.79. We conclude that QSPR models can be used to identify candidate drugs expected to have high remote loading capacity while simultaneously optimizing the design of formulation experiments.
Recently, developing drug delivery systems exhibiting controlled drug release at the tumor sites emerged as an attractive option for enhancing anticancer therapeutic efficacy. It seems, however, unlikely that single agent therapies will prove effective enough against the myriad cells present within the malignancy. Therefore, next generation nanotherapeutics must not only find their way to the solid tumor but also must effectively destroy the diverse populations of cells promoting tumor growth. Nanoliposomes offer an important advantage in the delivery of a combination of drugs acting synergistically in cancer treatment. They allow controlling the pharmacokinetics and biodistribution of the drugs by uniform time and spatial co-delivery of the agents. However, successful translation of such complex formulations into the clinic relies on understanding critical physicochemical characteristics. These include: liposomes' membrane phase and dynamics, size distribution, state of encapsulated drug, internal environment of liposome, state of grafted polyethylene glycol at the liposome surface, and in-vivo drug release rate. They determine the pharmacokinetics of the formulation and the bioavailability of the drugs. We encapsulated the combination of vincristine (VCR) and topotecan (TPT) in the same nanoliposome (LipoViTo). Our in-vitro and in-vivo characterization of LipoViTo provides an explanation for the good therapeutic efficacy that was previously reported by us. Moreover, we have described how to study these critical features for a two-drug in one nanoliposome formulation. This characterization is an important step for a rational clinical development and for how to ensure liposome product quality of LipoViTo and other liposomal formulations alike.
Some therapeutic liposomes and lipid excipient-based anticancer drugs are recognized by the immune system as foreign, leading to a variety of adverse immune phenomena. One of them is complement (C) activation, the cause, or major contributing factor to a hypersensitivity syndrome called C activation-related pseudoallergy (CARPA). CARPA represents a novel subcategory of acute (type I) hypersensitivity reactions (HSR), which is mostly mild, transient, and preventable by appropriate precautions. However, in an occasional patient, it can be severe or even lethal. Because a main manifestation of C activation is cardiopulmonary distress, CARPA may be a safety issue primarily in cardiac patients. Along with an overview of the various types of liposome-immune system interactions, this review updates the experimental and clinical information on CARPA to different therapeutic liposomes and lipid excipient-based (micellar) anticancer drugs, including PEGylated liposomal doxorubicin sulfate (PLD, Doxil®) and paclitaxel (Taxol®). The substantial individual variation of in vitro and in vivo findings reflects an extremely complex immune phenomenon involving multiple, redundant pathways of C activation, signal transduction in allergy-mediating cells and vasoactive mediator actions at the effector cell level. The latest advances in this field include the proposal of doxorubicin-induced shape changes and aggregation of liposomes in Doxil as possible contributing factors to CARPA caused by PLD, and the finding that Doxil-induced immune suppression prevents HSR to co-administered carboplatin, a significant benefit of Doxil in combination chemotherapy with carboplatin. The review evaluates the use of in vitro C assays and the porcine liposome-induced cardiopulmonary distress model for predicting CARPA. It is concluded that CARPA may become a frequent safety issue in the upcoming era of nanomedicines, necessitating its prevention at an early stage of nanomedicine R&D.
This study aimed to characterize the effect of polyethylene glycol of 2000 molecular weight (PEG2000) attached to a dialkylphosphatidic acid (dihexadecylphosphatidyl (DHP)-PEG2000) on the hydration and thermodynamic stability of lipid assemblies. Differential scanning calorimetry, densitometry, and ultrasound velocity and absorption measurements were used for thermodynamic and hydrational characterization. Using a differential scanning calorimetry technique we showed that each molecule of PEG2000 binds 136 +/- 4 molecules of water. For PEG2000 covalently attached to the lipid molecules organized in micelles, the water binding increases to 210 +/- 6 water molecules. This demonstrates that the two different structural configurations of the PEG2000, a random coil in the case of the free PEG and a brush in the case of DHP-PEG2000 micelles, differ in their hydration level. Ultrasound absorption changes in liposomes reflect mainly the heterophase fluctuations and packing defects in the lipid bilayer. The PEG-induced excess ultrasound absorption of the lipid bilayer at 7.7 MHz for PEG-lipid concentrations over 5 mol % indicates the increase in the relaxation time of the headgroup rotation due to PEG-PEG interactions. The adiabatic compressibility (calculated from ultrasound velocity and density) of the lipid bilayer of the liposome increases monotonically with PEG-lipid concentration up to approximately 7 mol %, reflecting release of water from the lipid headgroup region. Elimination of this water, induced by grafted PEG, leads to a decrease in bilayer defects and enhanced lateral packing of the phospholipid acyl chains. We assume that the dehydration of the lipid headgroup region in conjunction with the increase of the hydration of the outer layer by grafting PEG in brush configuration are responsible for increasing thermodynamic stability of the liposomes at 5-7 mol % of PEG-lipid. At higher PEG-lipid concentrations, compressibility and partial volume of the lipid phase of the samples decrease. This reflects the increase in hydration of the lipid headgroup region (up to five additional water molecules per lipid molecule for 12 mol % PEG-lipid) and the weakening of the bilayer packing due to the lateral repulsion of PEG chains.
Unlabelled:
Hypersensitivity reactions to liposomal drugs, often observed with Doxil and AmBisome, can arise from activation of the complement (C) system by phospholipid bilayers. To understand the mechanism of this adverse immune reaction called C activation-related pseudoallergy (CARPA), we analyzed the relationship among liposome features, C activation in human serum in vitro, and liposome-induced cardiovascular distress in pigs, a model for human CARPA. Among the structural variables (surface charge, presence of saturated, unsaturated, and PEGylated phospholipids, and cisplatin vs. doxorubicin inside liposomes), high negative surface charge and the presence of doxorubicin were significant contributors to reactogenicity both in vitro and in vivo. Morphological analysis suggested that the effect of doxorubicin might be indirect, via distorting the sphericity of liposomes and, if leaked, causing aggregation. The parallelism among C activation, cardiopulmonary reactions in pigs, and high rate of hypersensitivity reactions to Doxil and AmBisome in humans strengthens the utility of the applied tests in predicting the risk of CARPA.
From the clinical editor:
The authors studied complement activation-related pseudoallergy (CARPA) in a porcine model and demonstrate that high negative surface charge and drug effects leading to distortion of liposome sphericity might be the most critical factors leading to CARPA. The applied tests might be used to predict CARPA in humans.
To describe and analyze observed hypersensitivity reactions (HSR) from the randomized, multicenter phase III CALYPSO trial that evaluated the efficacy and safety of the combination of carboplatin and pegylated liposomal doxorubicin (CD) compared with standard carboplatin-paclitaxel (CP) in patients with platinum-sensitive relapsed ovarian cancer (ROC).
HSR documented within case report forms and SAE reports were specifically analyzed. Analyses were based on the population with allergy of any grade and for grade >2 allergy.
Overall 976 patients were recruited to this phase III trial, with toxicity data available for 466 and 502 on the CD and CP arms, respectively. There was a 15.5% HSR rate associated with CD (2.4% grade >2) versus 33.1% with CP (8.8% grade >2), p<0.001. HSRs occurred more often during first cycle in the CD (46%) arm than in the CP arm (16%). Multivariate predictors of allergy were chemotherapy regimen and age; patients randomized to CD and patients ≥ 70 years old on CP had less allergy. Few patients (<6%) stopped treatment due to allergy. Allergy rates were higher in patients who did not receive prior supportive treatment; however there was no relationship between allergy and the type of carboplatin product received, or response rate.
Use of PLD with carboplatin instead of paclitaxel and older age were the only 2 factors predicting a low rate of HSRs in patients with ROC. CD has previously demonstrated superior progression-free survival and therapeutic index than CP. Taken together these data support the use of CD as a safe and effective therapeutic option for platinum-sensitive ROC.
One challenge in developing a nanoparticle drug-delivery system is understanding the critical physicochemical properties that may impact its in vivo performance and establishing analytical techniques that can adequately characterize in vitro and in vivo properties. Doxil®/Caelyx®, a PEGylated liposomal doxorubincin (PLD), is one of the leading approved nanoparticle product used in cancer therapy. In this review, we use PLD as an example to illustrate identification of key in vitro and in vivo characteristics. The following characteristics, including liposome composition, state of encapsulated drug, internal environment of liposome, liposome size distribution, lamellarity, grafted polyethylene glycol at the liposome surface, electrical surface potential or charge, and in vitro leakage, are considered critical to demonstrate the supramolecular structure of PLD and ensure consistent drug delivery to cancer tissues. Corresponding analytical techniques are discussed to determine these liposome characteristics. Furthermore, in vivo stability of the PLD can be determined by plasma pharmacokinetics of both free and liposome-encapsulated drug. A better understanding of the critical in vitro and in vivo liposome characteristics together with improvements in analytical technology will enable generic liposome product development and ensure liposome product quality.
The dense collagen network in tumors significantly reduces the penetration and efficacy of nanotherapeutics. We tested whether losartan--a clinically approved angiotensin II receptor antagonist with noted antifibrotic activity--can enhance the penetration and efficacy of nanomedicine. We found that losartan inhibited collagen I production by carcinoma-associated fibroblasts isolated from breast cancer biopsies. Additionally, it led to a dose-dependent reduction in stromal collagen in desmoplastic models of human breast, pancreatic, and skin tumors in mice. Furthermore, losartan improved the distribution and therapeutic efficacy of intratumorally injected oncolytic herpes simplex viruses. Finally, it also enhanced the efficacy of i.v. injected pegylated liposomal doxorubicin (Doxil). Thus, losartan has the potential to enhance the efficacy of nanotherapeutics in patients with desmoplastic tumors.
There is an opportunity to improve the therapeutic potential of a combination of two drugs using nanoliposomes. The combination of topotecan (TPT) and vincristine (VCR) was selected. The ratio-dependent synergy between these two drugs was evaluated, in an attempt to improve the therapeutic efficacy of this combination in vivo. The interaction between the drugs was evaluated in tissue culture by the median-effect analysis. Certain ratios of combined drugs were synergistic, whereas, others were antagonistic, implying that the most efficacious combinations should be at a specific fixed drug ratio. For in vivo evaluation, nanoliposomes co-remotely loaded simultaneously with both drugs by transmembrane ammonium sulfate gradient were developed. VCR and TPT were successfully co-encapsulated at therapeutically relevant levels in the same nanoliposome (LipoViTo). The nanoliposomes controlled the drugs' "biofate" and maintained a fixed drug ratio in vivo, allowing one to compare the therapeutic efficacy of various predefined drug ratios. Pharmacokinetics and biodistribution studies showed that LipoViTo delivers the two drugs simultaneously to the tumors, where they are released at a predefined ratio. LipoViTo was more efficacious than the free drugs and liposomes with one agent, singly or in combination, in two tumor models in mice. LipoViTo co-loaded with both drugs corresponding to their maximal tolerated dose (MTD) ratio resulted in the best therapeutic efficacy. To summarize: liposomal co-encapsulation of anticancer drug combinations can profoundly influence therapeutic outcomes. Drug combinations can be optimized preclinically through pharmacokinetic control by remote loading into nanoliposomes.
Purpose:
To examine whether a conventional bioequivalence approach is sufficient to ensure the therapeutic equivalence of liposomal products, the pharmacokinetics, efficacy and toxicity of different formulation variants of the marketed Doxil(/Caelyx product, pegylated liposomal doxorubicin (PLD), were evaluated in several preclinical models.
Methods:
Six different variants of the marketed PLD formulation were prepared by incorporating minor changes in the composition and liposome size of the original formulation. The pharmacokinetics of 5 formulations were evaluated in albino mice following i.v. administration at 6 mg/kg. Selected variants along with Doxil/Caelyx (formulation 1, Doxil-control) were tested for antitumor activity in the MDA-MB-231 xenograft mouse model following 3 repeated administrations at 2 mg/kg or 3 mg/kg (once weekly for 3 weeks) and/or toxicity in Cynomolgus monkeys following 6 repeated administrations at 2.5 or 4.0 mg/kg. Formulations 1-4 were tested for antitumor activity and formulations 1, 2, 6 and 7 were evaluated in a monkey toxicity study. The toxicokinetics of total doxorubicin was determined after the first and last dose in the monkey toxicity study.
Results:
In the albino mouse, formulations 2 and 3 had plasma pharmacokinetic profiles similar to Doxil-control (formulation 1). Although these three formulations had similar pharmacokinetic profiles, formulation 2 showed significantly (P < 0.05) longer survival time and better efficacy (reduced tumor volume) over other formulations tested for antitumor activity at the 3 mg/kg dose. In monkeys, formulation 2 gave systemic exposure of doxorubicin approximately the same as formulation 1; however, multi-focal degeneration of renal cortical tubules and hypocellularity of the bone marrow were observed with formulation 2 but not with formulation 1 (Doxil-control). Formulations 6 and 7 gave lower exposure to doxorubicin compared to Doxil-control, but were associated with higher severity and frequency of toxic effects (hematological effects, elevated liver enzymes). It was concluded that plasma pharmacokinetics and systemic exposure of doxorubicin did not correlate well with the antitumor activity and toxicity profiles for PLD products. Hence, a conventional bioequivalence approach is not appropriate for establishing therapeutic equivalence of generic PLD products. A carefully designed clinical study evaluating clinical safety, efficacy and pharmacokinetics should be considered for establishing the therapeutic equivalency of generic versions of Doxil.
Remote loading of liposomes by transmembrane gradients is one of the best approaches for achieving the high enough drug level per liposome required for the liposomal drug to be therapeutically efficacious. This breakthrough, which enabled the approval and clinical use of nanoliposomal drugs such as Doxil, has not been paralleled by an in-depth understanding that allows predicting loading efficiency of drugs. Here we describe how applying data-mining algorithms on a data bank based on Barenholz's laboratory's 15 years of liposome research experience on remote loading of 9 different drugs enabled us to build a model that relates drug physicochemical properties and loading conditions to loading efficiency. This model enables choosing candidate molecules for remote loading and optimizing loading conditions according to logical considerations. The model should also help in designing pro-drugs suitable for remote loading. Our approach is expected to improve and accelerate development of liposomal formulations for clinical applications.
For over half a century extensive research has been undertaken for the control of cancer. However, success has been limited to certain malignancies, and surgical intervention is potentially curative for early stage patients. For the majority of patients with advanced stage of cancer, the treatment is limited to chemotherapy or radiation. Chemotherapy in particular has limitations due to the lack of selectivity with severe toxicity. Under these circumstances tumor-targeted delivery of anticancer drugs is perhaps one of the most important steps for cancer chemotherapy. We reported such a drug for the first time, styrene-maleic acid copolymer-conjugated neocarzinostatin (SMANCS) in 1979, and it eventually led to formulate the concept of the enhanced permeability and retention (EPR) effect of solid tumors in 1986. Monoclonal antibody conjugates are another direction, of which interest is increasing recently though with limited success. The EPR-effect appears as a universal phenomenon in solid tumors which warrants the development of other polymeric drugs or nanomedicine.
Combination chemotherapy with CHOP (cyclophosphamide, Adriamycin, vincristine, and prednisone) and HOP (Adrimycin, vincristine, and prednisone, was used as treatment for patients with pathologically staged, advanced non-Hodgkin's lymphoma. Among 204 evaluable patients treated on CHOP there were 71% complete remissions with 92% overall responses. Among the 216 evaluable patients on HOP there were 61% complete remissions and 88% responses. Complete remission rates among patients with histiocytic lymphoma were comparable to those of patients with lymphocytic disease. Patients with nodular lymphoma had higher rates of complete remission than their counterparts with diffuse lymphoma. This was noted with both CHOP (78% vs. 67%) and HOP (67% vs. 60%) induction therapy. Rapid responses were common, as more than 14% of complete remissions and 66% of overall responses were achieved with the first course of treatment. Patients in complete remission have been maintained with either cyclophosphamide, vincristine, and prednisone (COP) or arabinosyl cytosine, vincristine, and prednisone (OAP). After 1 year, 86% of patients on COP and 80% on OAP are projected to be free of disease.
Liposomes can be loaded with weak acids and bases, which exist in solutions in equilibrium with membrane permeable uncharged form, using various gradients across their membranes. Because in some cases the estimated drug concentration in the loaded liposomes exceeds their aqueous solubility we investigated the physical state of the liposome encapsulated anticancer drug Doxorubicin. X-Ray diffraction, electron microscopy, and test tube solubility experiments have shown that upon encapsulation the drug molecules form a gel-like phase.
The anthracyclines are the class of antitumor drugs with the widest spectrum of activity in human cancers, and only a few cancers (eg, colon cancer) are unresponsive to them. The first two anthracyclines were developed in the 1960s. Doxorubicin (DOX) differs from daunorubicin (DNR) only by a single hydroxyl group. This fact has spurred researchers worldwide to find analogs of DOX that have less acute toxicity, cause less cardiomyopathy, can be administered orally, and/or have different, or greater, antitumor efficacy. Five DOX/DNR analogs are marketed in other countries, and one (idarubicin) is available in the United States. None of these analogs have stronger antitumor efficacy than the original two anthracyclines, but there are some differences in toxicity. Methods have been fashioned to keep the peak plasma level of DOX muted to minimize cardiotoxicity, but the only apparently effective method available so far (prolonged drug infusion) is cumbersome. The bisoxopiperazine class of drugs (especially dexrazoxane) provides protection against anthracycline-induced cardiomyopathy and has much promise for helping mitigate this major obstacle to prolonged use of the anthracyclines. The DOX analogs being evaluated in the 1990s have been selected for their ability to overcome multidrug resistance in cancer cells. Thirty years after discovery of the anticancer activity of the first anthracycline, some means of reducing anthracycline toxicity have been devised. Current studies are evaluating increased doses of epirubicin to improve anthracycline cytotoxicity, while limiting cardiotoxicity, but at present DOX still reigns in this drug class as the one having the most proven cancerocidal effect.
Many recent reports have demonstrated that rapid uptake of liposomes in vivo by cells of the mononuclear phagocytic system (MPS), which has restricted their therapeutic utility, can be overcome by incorporation of lipids derivatized with the hydrophilic polymer polyethylene glycol (PEG). The structure-function relationship of PEG-derivatized phosphatidylethanolamine (PEG-PE) has been examined by measurement of blood lifetime and tissue distribution in both mice and rats. The results are reviewed and contrasted with those from liposomes without PEG-PE or other surface modifications. With a PEG molecular weight in the range of 1000 to 5000, prolonged circulation and reduced MPS uptake is achieved. After 24 h, up to 35% of the injected dose remains in the blood and less than 10% is taken up by the two major organs of the MPS, liver and spleen, compared with 1% and up to 50%, respectively, for liposomes without PEG-PE. Other important advantages of PEG-PE have been identified: prolonged circulation is independent of liposome cholesterol content, degree of hydrocarbon chain saturation in either the PC or the PE lipid anchor, lipid dose, or addition of most other negatively charged lipids. This versatility in lipid composition and dose is important for controlling drug release in a liposome-based therapeutic agent. Steric stabilization has been proposed as a theoretical basis for the results and some initial results testing this hypothesis have been reported. A description of a theoretical model is presented here and evaluated with the data available. The results are compared with other particulate drug carriers and the range of potential applications are considered.
We have investigated the in vitro cytotoxicity of free doxorubicin (DOX) and liposome-entrapped DOX (L-DOX) against a human ovarian carcinoma cell line (OV-1063) using a colorimetric assay. DOX was encapsulated in the inner water phase of liposomes by an ammonium sulfate-generated proton gradient. Liposomes varied in phospholipid composition but were of a similar size. It was found that the cytotoxic activity of L-DOX is substantially decreased when liposomes containing phospholipids of high phase-transition temperature (Tm) are used. The type of negatively charged headgroup did not have any significant influence on the cytotoxicity observed. Experiments using resin beads that bind free and protein-bound DOX, but do not interact with L-DOX, indicated that the cytotoxic effect is mediated by the release of drug from the liposomes into the extracellular medium; no evidence was found for direct cellular uptake of liposome-encapsulated drug. The use of the ionophore nigericin to induce the release of DOX from high-Tm liposomes increased cytotoxicity to a level comparable to free DOX, suggesting that 'remote release' techniques may substantially improve the efficiency of liposome-mediated drug delivery and allow for the full exploitation of the favorable pharmacokinetic properties of specific high-Tm formulations.