Yordan Yordanov

• Doctor of Pharmacy
• Professor (Associate) at Medical University of Sofia

Background/Objectives: Natural substances have been a widely studied source of both pharmaceutical excipients and drugs. Berberine (BRB) is a benzylisoquinoline alkaloid isolated from different plant sources. It possesses various pharmacological properties including antibacterial, antitumor, antidiabetic, neuroprotective, hepatoprotective, anti-inf...

The simultaneous encapsulation of drugs into nanosized delivery systems could be beneficial for cancer therapies since it could alleviate adverse reactions as well as provide synergistic effects. However, the encapsulation of hydrophobic drugs into hydrophilic nanoparticles, such as nanogels, could be challenging. Therefore, innovative technologica...

Neurodegenerative diseases such as Parkinson’s and Alzheimer’s continue to be some of the most significant challenges in modern medicine. Recent research related to the molecular mechanisms of parkinsonism has opened up new approaches to antiparkinsonian therapy. In response to this, we present the evaluation of the potential neuroprotective and MA...

The therapeutic approach to many solid tumors, including non-small cell lung cancer (NSCLC), is mainly based on the use of platinum-containing anticancer agents and is often characterized by acquired or intrinsic resistance to the drug. Therefore, the search for safer and more effective drugs is still an open challenge. Two organometallic rutheniu...

Mesoporous silica nanoparticles (MSNs) are inorganic nanocarriers presenting versatile properties and the possibility to deliver drug molecules via different routes of application. Their modification with lipids could diminish the burst release profile for water-soluble molecules. In the case of oleic acid (OA) as a lipid component, an improvement...

Resveratrol could be applied in wound healing therapies because of its antioxidant, anti-inflammatory and antibacterial effects. However, the main limitation of resveratrol is its low aqueous solubility. In this study, resveratrol was included in hydroxypropyl-β-cyclodextrin complexes and further formulated in Pluronic F-127 hydrogels for wound tre...

РЕЦЕНЗИЯ на монографията „Анализ на изображения в експерименталната токсикология“ от гл. ас. Йордан Иванов Йорданов, дф Монографичният труд на гл.ас. доктор Йордан Йорданов на тема „Анализ на изображения в експерименталната токсикология“ се появява в период от развитието на науката и технологиите, в който въпросите за коректната обработка на го...

The human knee is a complex joint that comprises several ligaments, including the medial collateral ligament (MCL). The MCL provides stability to the knee and helps prevent its excessive inward movement. The MCL also has a thin layer of connective tissue known as the epiligament (EL), which adheres to the ligament. This unique feature has drawn att...

The aim of this study was to assess the epiligament theory by determining the normal epiligament morphology of the proximal and distal parts of the anterior cruciate ligament in humans and analyzing the differences between them and the midportion of the ligament in terms of cell numbers and expression of CD34 and α-SMA. Samples were obtained from t...

A series of ten new hydrazide–hydrazone derivatives bearing a pyrrole ring were synthesized and structurally elucidated through appropriate spectral characteristics. The target hydrazones were assessed for radical scavenging activity through 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) test...

Nanogels are attractive drug delivery systems that provide high loading capacity for drug molecules, improve their stability, and increase cellular uptake. Natural antioxidants, especially polyphenols such as resveratrol, are distinguished by low aqueous solubility, which hinders therapeutic activity. Thus, in the present study, resveratrol was inc...

The anthracycline antibiotic doxorubicin is a well-known antitumour agent, however its cardiotoxicity is a significant obstacle to therapy. The aim of the present study was to improve the safety of doxorubicin through its simultaneous encapsulation with a cardioprotective agent (resveratrol) in Pluronic micelles. The formation and double-loading of...

The present study is focused on the development of cannabidiol-loaded polymeric nanomicelles as a drug delivery system with neuroprotective effects. Cannabidiol was loaded in Pluronic micelles (Pluronic P123 or its combination with Pluronic F127) possessing an average diameter smaller than 50 nm and high encapsulation efficiency for the hydrophobic...

Background: Necrotizing enterocolitis (NEC) is a major health burden in peterm neonates with mortality rates between 21% and 50%. Prophylaxis is of primary importance as early diagnosis is hindered by the lack of specific signs and laboratory markers. Although probiotics have been routinely used for NEC prophylaxis in neonatal intensive care units...

Background This study evaluated and compared the expression of VEGF, CD34, and α-SMA in the anterior cruciate ligaments and medial collateral ligaments in healthy human knees in order to enrich the epiligament theory regarding ligament healing after injury. Methods Samples from the mid-substance of the anterior cruciate ligament and the medial col...

Sdox is a hydrogen sulfide (H2S)-releasing doxorubicin effective in P-glycoprotein-overexpressing/doxorubicin-resistant tumor models and not cytotoxic, as the parental drug, in H9c2 cardiomyocytes. The aim of this study was the assessment of Sdox drug-like features and its absorption, distribution, metabolism, and excretion (ADME)/toxicity properti...

Abstarct A synthetic strategy towards modular polymer platform capable of further tunable degree of modification is presented. Initially, a well-defined amphiphilic block copolymer with alkyne side groups distributed along the biodegradable hydrophobic block was successfully prepared applying controlled ring-opening copolymerization of D,L-lactide...

Caffeic acid phenethyl ester (CAPE), a major pharmacologically active component of poplar type propolis, is known for its proapoptotic, anti-inflammatory, antioxidant, antiviral, and enzyme inhibiting activities. The aim of this study was to perform an in vitro and in vivo safety assessment of a micellar system based on a newly synthesized copolyme...

Six new N -pyrrolylhydrazide hydrazones were synthesized under micro synthesis conditions, assuring about 59–93 % yield, low harmful emissions and reagent economy. The structures of the new compounds were elucidated by melting points, TLC characteristics, IR, ¹ H and ¹³ C NMR spectral data followed by MS data. The purity of the obtained compounds w...

The present study evaluated the impact of doxorubicin encapsulation in chitosan-alginate nanoparticles on its stability, cytotoxic potential in multidrug resistant lymphoma cells (L5178 MDR1) and toxicity in H9c2 cardioblasts. The results indicated that the encapsulation stabilized the drug against degradation due to its inner location in nanoparti...

Propolis is a natural product with a plethora of biological effects, utilized by traditional medicine since antiquity. However, its application as a pharmaceutical is hindered by its variable composition and difficult standardization. CAPE has been shown to be a major component of propolis, with a large contribution to its pharmacological effects,...

Phase-contrast micrographs are often used for confirmation of proliferation and viability assays. However, they are usually only a qualitative tool and fail to exclude with certainty the presence of assay interference by test substances. The complexity of image analysis workflows hinders life scientists from routinely utilizing micrograph data. Her...

Caffeic acid phenethyl ester (CAPE) is the major pharmacologically-active component of some propolis types, rich in polyphenols, such as poplar propolis types. CAPE has the potential to be applied as a pharmaceutical as it possesses most of the pharmacological activities of propolis, such as anti-proliferative, antioxidant, immunomodulatory, antidi...

Amphiphilic diblock copolymers consisting of hydrophilic polyglycidol (PG) and hydrophobic poly(allylglycidyl ether) (PAGE) were prepared by sequential anionic ring‐opening polymerization of allylglycidyl ether and ethoxyethyl glycidyl ether followed by removal of the protective ethoxyethyl groups. The polymerization was initiated by partially depr...

In this study, spherical hollow mesoporous silica (HMS) particles with average size of 550 nm were loaded with dopamine-receptor agonist pramipexole, as a model drug. High drug loading (55%) was achieved by its incorporation in the reservoir structure of HMS. The newly developed drug-delivery systems were further double-coated with bioadhesive poly...

The present study reports a promising antioxidant protection by a recently developed micellar propolis formulation, against oxidative stress in in vitro and in vivo models of toxicity. The formulation, based on poplar propolis encapsulated in poly(ethylene oxide)–b-poly(propylene oxide)–b-poly(ethylene oxide) triblock copolymer (PEO26–PPO40–PEO26)...

Lomefloxacin (LF) is interesting as a model molecule from a safety point of view because of its high potential for serious adverse drug effects (i.e. phototoxic reactions). In this study, MCM-41 mesoporous silica nanoparticles (MCM-41) were loaded with lomefloxacin, aiming to overcome the drug’s intrinsic cytotoxicity. The good biocompatibility of...

Herein, we present development of new pH-responsive drug delivery systems for D3-dopamine receptor agonist pramipexole, based on its encapsulation in MCM-41 mesoporous silica particles. Pramipexole loaded particles were further coated with chitosan and/or sodium alginate in order to modify drug release. The prepared pramipexole loaded nanoparticles...

Caffeic acid phenethyl ester (CAPE), a hydrophobic constituent of poplar propolis of valuable biological activity, was immobilized in poly(ethylene oxide)-b-poly(ε-caprolactone)-b-poly(ethylene oxide) (PEO-b-PCL-b-PEO) copolymer micelles to improve its solubility in water. CAPE was loaded in the micelles by dialysis, achieving ca. 50% encapsulation...

Nanomedicine and nanopharmacy are relatively new and promising branches of medical science. They apply specific approaches for overcoming therapy limitations such as: low selectivity, impermeability of biological membranes, unfavorable physicochemical properties and pharmacokinetics of drugs. Nanomedicines are systems with finely controlled charact...

Nanotoxicology evaluates the relationship between the structure properties of nanoparticles and toxic hazard, which is of considerable importance prior to clinical application of nanosystems. In spite of the introduction of nanotoxicology in regulatory affairs and the elucidation of some physicochemical structure - toxicity relationships by means o...

The aim of the present study was to evaluate the protective effects of free and encapsulated quercetin against oxidative stress injury in neuronal SH-SY5Y cells and isolated rat brain synaptosomes. Quercetin (QR) was encapsulated in nanoparticles consisting of sodium alginate and chitosan and the ratio between both biopolymers was 10:1 or 1:10, res...

The toxic liver impairment caused by free radical injury or excessive reactive oxigen species (ROS) formation could be effectivelly attenuated by natural antioxidants. The present study aimed to explore and compare the hepatoprotective and antioxidant effects of free and encapsulated quercetin in in vitro and in vivo models of hepatotoxicity. Thus,...

The present study deals with development and evaluation of the safety profile of chitosan/alginate nanoparticles as a platform for delivery of a natural antioxidant quercetin. The nanoparticles were prepared by varying the ratios between both biopolymers giving different size and charge of the formulations. The biocompatibility was explored in vitr...

The numerous beneficial pharmacological properties of quercetin justify its future clinical application. Nevertheless, the use of quercetin as a safe and effective therapeutic agent in the treatment of various diseases is limited because of the poor water solubility and membrane permeability, low bioavailability and instability. Several approaches...

The present study aims to explore the protective effects of pramipexol loaded in mesoporous silica particles in a model of oxidative stress damage in human neuroblastoma SH-SY5Y cells in vitro. Pramipexol is a dopamine agonist which is applied for the treatment of early and advanced Parkinson's disease. Mesoporous silica nanoparticles are attractiv...

Curcumin is a polyphenolic substance with attractive pharmacological activities (e.g. antioxidant, anti-inflammatory, anticancer). Incorporation of curcumin in polymeric micelles could overcome the problems associated with its instability and low aqueous solubility. The aim of this study was to load curcumin in polymeric micelles based on Pluronic®...