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Carbopol and its Pharmaceutical Significance: A Review
Abstract
In the recent decades, there has been considerable interest in using Carbopolas an excipient in a diverse range of pharmaceutical applications.Carbopol polymers are polymers of acrylic acid cross-linked with polyalkenyl ethers or divinyl glycol. They are produced from primary polymer particles of about 0.2 to 6.0 micron average diameter. The flocculated agglomerates cannot be broken into the ultimate particles when produced. Each particle can be viewed as a network structure of polymer chains interconnected via cross-linking1.Carbomers were first prepared and patented in 19572. Since then, a number of extended release tablet formulations, which involve carbomer matrices, have been patented3.Carbomers readily absorb water, get hydrated and swell. In addition to its hydrophilic nature, its cross-linked structure and its essentially insolubility in water makes Carbopol a potential candidate for use in controlled release drug delivery system.4,5
... The carboxyl groups present in the acrylic acid chain are responsible for several of their characteristics, such as gel formation due to ionization of the chains and electrostatic repulsion of the negatively charged groups when neutralized, thus being able to release the drug molecules at the site of action. However, pedant carboxylic acid groups at low pH values remain non-ionized and retain the drug inside [19,[22][23][24][25]. The ability to absorb water, hydrate and swell, maintaining the reticulated structure and the insolubility in water, makes the carbomers excellent bio/mucoadhesive polymers [26]. ...
... Some studies have evaluated the toxicity of this type of polymer and demonstrated low toxicity and low irritant potential. Therefore, carbomers are widely accepted as a bioadhesive in many applications [19,21,23] and several types are reported and differentiated by the degree of reticulation and manufacturing conditions [18,23]. Carbopol 934P (934P) is highly cross-linked with excellent stability at high viscosities, which confers excellent bioadhesive and viscoelastic properties. ...
... Some studies have evaluated the toxicity of this type of polymer and demonstrated low toxicity and low irritant potential. Therefore, carbomers are widely accepted as a bioadhesive in many applications [19,21,23] and several types are reported and differentiated by the degree of reticulation and manufacturing conditions [18,23]. Carbopol 934P (934P) is highly cross-linked with excellent stability at high viscosities, which confers excellent bioadhesive and viscoelastic properties. ...
Semi-solid emulsion systems constitute important platforms for drug delivery, due to the easiness of administration, increasing residence time and also improve the drug availability. They are usually stabilized by emulsifiers and hydrophilic polymers may be used to form a tridimensional network in the hydrophilic phase resulting in a structure than can disperse the hydrophobic phase and the drug. These systems can be administered by oral, parenteral, and topical routes as platforms for delivery of biologically active agents from different origins such as mineral, animal or vegetal. Propolis has a complex chemical composition and displays many important biological activities (antibacterial, fungicidal, antioxidant, antiviral, anti-inflammatory, immunostimulant, anti-cancer, antiulcer, hypotensive and cytostatic). Propolis ethanolic extract (PE) and extract of propolis by-product (BPE) are usually utilized in therapeutics. In this work, three vegetable oils (passion fruit, andiroba and sweet almond oils) were used to develop emulsion-systems composed of Carbopol 934P (C934P) for propolis delivery. The mechanical and rheological properties of formulations were investigated to select potential emulsion systems. A factorial design was employed to determine the influence of C934P concentration and the different vegetable oils on the physicochemical characteristics of systems, considering the presence of PE or BPE. Emulsion systems displayed physicochemical stability and mechanical characteristics dependent of C934P 1% (w/w). Formulations displayed pseudoplastic flow behavior and viscoelasticity dependent of vegetable oil type, temperature and type of propolis extract. The results indicated that the PE resulted in a more structured emulsion system due to the greater content of resin and gum than the BPE. Emulsion systems displayed softness and are worthy of investigation intended the administration on the skin and mucous membranes.
... These agents are also known to be thickening agents, stabilizers, and solidifiers [21]. Among these, the carbomers are polymers of acrylic acid (AA) cross-linked with divinyl glycol or poly-alkenyl ethers [14]. They have extensively been used in the development of topical and transdermal drug delivery systems. ...
Low permeability is one of the barriers to the bioavailability of drugs through the oral route. The purpose of the present study was to design and optimize a sustained release and highly permeable hydrogel formulation of ganciclovir (GCV) by using response surface methodology (RSM). Carbopol 934P was used as a gelling agent, with two permeation enhancers, i.e., propylene glycol (PG) and oleic acid (OA), which were selected as variables X1 and X2, respectively. A total number of 13 runs prepared by using a central composite rotatable design (CCRD), followed by the preparation and evaluation of various parameters, including flux, lag time, Kp, and the rheological studies were evaluated. FTIR analysis showed that there was no interaction between the drug, polymer, and other excipients. The outcomes of ex vivo permeation studies have reviled that the values of flux, lag time, and kp were found to be 2.08800 ± 0.008, −6.982638 ± 0.01, −2.6917 ± 1.21, −29.7116 ± 0.68, and 0.00020, −0.00069, respectively. The spreadability index and the viscosity of the gel formulations were between the range of 2.63 ± 0.12–3.50 ± 0.08 and 5013.66 ± 1.69–5077.66 ± 2.05, respectively. On the other hand, the pH of all preparations was maintained at 7.02–7.13 pH to avoid skin irritation. After evaluating the said parameters, the composition for the optimized formulation is PG 5gm, OA 0.4gm, and carbopol 0.5gm. Furthermore, the findings have advocated that the hydrogels could be used, not only to deliver the drug in a sustained manner but also to improve the permeation of the drug and hence its bioavailability.
... To achieve maximum performance of the polymer, the molecule must be completely uncoiled. This can be realized by neutralizing the polymer with a suitable alkaline ingredient (e.g., sodium hydroxide, potassium hydroxide, or triethanolamine), Figure S1 [17][18][19][20][21]. These types of gels can be used to obtain dispersions with substances that can be included in different classes of the Biopharmaceutics Classification System (BCS) (e.g., benzoic acid, boric acid 10%, benzocaine 1%, zinc oxide 20%, sulfathiazole 5%) [22]. ...
The development of semisolid formulations, gels in particular, has raised the attention of scientists more and more over the last decades. Because of their biocompatibility, hydrophilic nature, and capacity of absorbing large quantities of water, hydrogels are still one of the most promising pharmaceutical formulations in the pharmaceutical industry. The purpose of this study is to develop an optimal formulation capable of incorporating a water-poorly soluble active ingredient such as miconazole used in the treatment of fungal infections with Candida albicans and Candida parapsilosis. A D-optimal design was applied to study the relationship between the formulation parameter and the gel characteristics. The independent parameters used in this study were the Carbopol 940 concentration (the polymer used to obtain the gel matrix), the sodium hydroxide amount, and the presence/absence of miconazole. Ten different dependent parameters (Y1–Y10) were evaluated (penetrometry, spreadability, viscosity, and tangential tension at 1 and 11 levels of speed whilst destructuring and during the reorganization of the gel matrix). The consistency of the gels ranged from 23.2 mm (GO2) to 29.6 mm (GM5). The least spreadable gel was GO7 (1384 mm2), whilst the gel that presented the best spreadability was GO1 (3525 mm2). The viscosity and the tangential stress at the selected levels (1 and 11) varied due to the different compositions of the proposed gels. The gels were also tested for drug content and antifungal activity. All determinations had satisfying results; the drug content was within limits accepted by Ph. Eur. 10 and all formulations containing miconazole exhibited antifungal activity. An optimal formulation with miconazole was attained, consisting of 0.84% Carbopol 940 and 0.32% sodium hydroxide.
... Carbopol (CP) is also a polymer composed of acrylic acid monomers. They have the ability to absorb and retain water and are available in a wide range of cosmetic and medicinal products and gels as emulsifying, suspending, thickening [28,29]. Carbopol is commonly used in the manufacture of facial moisturizers, sunscreens, shampoos, anti-aging products, eye creams, cleansers and scrubs [30]. ...
Scaffold as a major part of tissue engineering plays an important role in the repairing process of the bone lesions. The scaffold's hydrophilicity plays a fundamental role in the initial cell attachment, and their growth, proliferation and differentiation processes. The aim of this study was to investigate the impact of hydrophilicity increasing in the hydrophobic scaffolds while combined with hydrophilic polymers on the osteogenic differentiation of induced pluripotent stem cells (iPSCs). In the present study, hydrophilicity of Polycaprolactone (PCL) electrospun nanofibers was improved using incorporating polyvinyl alcohol (PVA) and Carbopol (CP). Water uptake assay was confirmed that the hydration value of the PCL/PVA/CP was significantly increased in comparison with PCL and PCL/PVA nanofibers. In addition, the viability of the iPSCs grown on the PCL/PVA/CP was also significantly increased in comparison with the other two groups. Osteogenic differentiation evaluation demonstrated that the highest ALP activity and total calcium was detected in the iPSCs grown on the PCL/PVA/CP compared to the cells cultured on the PCL/PVA nanofibers. Although these values in the iPSCs cultured on the PCL/PVA was also significantly higher than those cells cultured on the PCL as a control group. Bone-related gene expression was also examined in the iPSCs cultured on the fabricated scaffolds. The results revealed that the highest expression level of genes was detected in the cells grown on the PCL/PVA/CP nanofibers. Taken together, these results indicated that the PCL/PVA/CP nanofibrous scaffold has greater osteoinductive potential than PCL/PVA and PCL nanofibers and could be considered as a potential construct in bone tissue engineering applications.
... Generally, toothpastes and oral care products are neutral or slightly acidic in terms of pH although whitening and bleaching formulations contain acids which make them slightly more acidic. Carbopols (Fig. 4b) or polycarbophiles are polymers of acrylic acid that are weakly cross-linked with polyalkenyl ethers or divinylglycol [93]. Their mucoadhesive properties come from the carboxylic groups and their ability to form strong hydrogen bonds between the polymer and the oligosaccharide chains present in the mucin. ...
This review explores the physical, chemical and structural properties of key components of oral care products, whilst looking at the challenges which need to be overcome to continue to improve the efficacy of oral care, and improve dental health. Oral care has been an essential part of all populations and cultures around the world for thousands of years. To maintain good oral health, dental plaque causing bacteria and malodour must be controlled whilst also strengthening and protecting the teeth to prevent dental caries. Advanced modern formulations need to provide controlled and extended release of ingredients vital for dental health. With modern day products such as toothpastes and mouthwashes, it has never been easier to maintain good oral hygiene and health, yet the incidence of dental caries is still on the rise. The complex formulations of modern toothpastes and mouthwashes makes them one of the most sophisticated pharmaceutical products on the market today. The demands of the consumer coupled with the complexity of the oral cavity make it one of the most challenging development processes.
... [13] Carbomers gel have a potential wide range of applicability in the pharmaceutical and dermocosmetic fields due to their high viscosity at low concentration, wide viscosity interval and characteristic flow behavior, compatibility with many active ingredients, good thermal stability, excellen to rgano-leptic characteristics, good patient acceptance and a potential candidate for use in controlled release drug delivery system. [16] The carbomer gel was kindly provided by Dr. Shahtalebi (Participating laboratories doctor Shahtalebi, Isfahan, Iran). Prepared gel was applied on lesions once a day, for 2 weeks in four mice and 3 weeks in four other mice in each group. ...
Background: Leishmaniasis is a major health problem in some endemic areas of tropical and subtropical
areas of the world. Interleukin‑12 (IL‑12) and interferon gamma (IFN‑γ) are essential cytokines associated
with initiation of Th1 response. The main objective of this study was to evaluate of the type of immune
response to L. major isolates from patients with no clinical response to antimonite (Glucantime).
Materials and Methods: This experimental study was carried out during 2013–2014. In the current study
Leishmania major were isolated from 10 CL patients with a history of at least one course of treatment with
Meglumine antimonate (Sb5). The isolates were used to evaluate in vitro and in vivo response to Sb5. J774
murine macrophage cell line was used for in vitro tests and Balb/c mice was used for in vivo studies. IL‑12 gene
expression was evaluated using Real‑time PCR and IFN‑γ serum level was quantified using ELISA technique.
SPSS (version: 20), analysis of Covariance (ANCOVA) was used for statistical analysis.
Results: PCR results confirmed that all 10 isolates were L. major. The mean of IL‑12 gene expression
in vitro, in vivo and IFN‑γ serum levels (pg/ml) after 2 and 3 weeks treatment in vivo, increased significantly
following the treatment with Glucantime in the two groups of Balb/c mice infected either with patients’
isolates or standard L. major. No significant difference was seen between the patients’ isolates and
standard species.
Conclusions: Although the L. major were isolated from patients with active lesion and no clinical response
to Glucantime after at least one courses of Glucantime treatment but in vivo and in vitro immune response
of L. major isolates showed no difference between the patients’ isolates and standard L. major.
Key Words: Clinical resistant, gene expression, glucantime, il–12, ifn–γ, immune responses, leishmania major
... [13] Carbomers gel have a potential wide range of applicability in the pharmaceutical and dermocosmetic fields due to their high viscosity at low concentration, wide viscosity interval and characteristic flow behavior, compatibility with many active ingredients, good thermal stability, excellen to rgano-leptic characteristics, good patient acceptance and a potential candidate for use in controlled release drug delivery system. [16] The carbomer gel was kindly provided by Dr. Shahtalebi (Participating laboratories doctor Shahtalebi, Isfahan, Iran). Prepared gel was applied on lesions once a day, for 2 weeks in four mice and 3 weeks in four other mice in each group. ...
... Hydrophilic polymers like guar gum and carbopol 940 were selected and 0.1N NaOH solution used as cross linking agent 11,12 . Carbopol 940 is soluble in water while guar gum produces colloidal dispersion in water. ...
Aceclofenac, a non-steroidal anti-inflammatory drug has been used in the treatment of rheumatoid arthritis and osteoarthritis. In order to decrease the gastric ulcerogenic effects, aceclofenac hydrogel have been developed. Topical gel preparations are intended for skin application or to certain mucosal surfaces for local action or transdermal penetration of medicament or for their emollient or protective action. Topical delivery of drugs can be achieved by incorporating drug into the gel matrix for effective delivery of drugs, thus avoiding first pass metabolism and for increased local action in pain management and skin diseases. NSAID’s are non-steroidal drugs having excellent anti-inflammatory and analgesic activity but NSAID’s produces GIT ulceration, liver and kidney trouble especially in case of oral administration. In view of adverse drug reaction associated with oral formulations, many NSAID’s are increasingly administered by topical route. Hydrophilic polymers like Guar gum and Carbopol 940 of varying concentrations were used in an attempt to develop topical hydrogel formulations of aceclofenac. Evaluation tests for visual appearance, pH, viscosity, spreadability, assay, in vitro drug release were carried out. In vitro diffusion study was carried out in a Franz diffusion cell using cellophane membrane. No prominent changes in physicochemical properties of formulation were observed after exposure to accelerated conditions of temperature (40 ± 2oC) and humidity conditions (75 ± 5%RH). The gel formulation consisting of 1% w/v Guar gum 1% w/v Carbopol 940 at 1:1 ratio was found to be suitable for topical application based on in vitro evaluation. These results suggest the feasibility of the topical gel formulation of aceclofenac. Keywords: Aceclofenac, Guar gum, Carbopol 940, Topical hydrogel, Franz diffusion cell
... They are anionic and therefore offer increased mucoadhesion hence contact time [13]. In addition, CP is reported to open the cellular tight junctions and could promote trans-corneal penetration of glutathione [14]. PVA has been used extensively in ocular formulations due to its ability to maintain ocular osmotic pressure while PAA has been widely used as a viscosity enhancer [2]. ...
... [13] Carbomers gel have a potential wide range of applicability in the pharmaceutical and dermocosmetic fields due to their high viscosity at low concentration, wide viscosity interval and characteristic flow behavior, compatibility with many active ingredients, good thermal stability, excellen to rgano-leptic characteristics, good patient acceptance and a potential candidate for use in controlled release drug delivery system. [16] The carbomer gel was kindly provided by Dr. Shahtalebi (Participating laboratories doctor Shahtalebi, Isfahan, Iran). Prepared gel was applied on lesions once a day, for 2 weeks in four mice and 3 weeks in four other mice in each group. ...
Background:
Leishmaniasis is a major health problem in some endemic areas of tropical and subtropical areas of the world. Interleukin-12 (IL-12) and interferon gamma (IFN-γ) are essential cytokines associated with initiation of Th1 response. The main objective of this study was to evaluate of the type of immune response to L. major isolates from patients with no clinical response to antimonite (Glucantime).
Materials and Methods:
This experimental study was carried out during 2013–2014. In the current study Leishmania major were isolated from 10 CL patients with a history of at least one course of treatment with Meglumine antimonate (Sb5). The isolates were used to evaluate in vitro and in vivo response to Sb5. J774 murine macrophage cell line was used for in vitro tests and Balb/c mice was used for in vivo studies. IL-12 gene expression was evaluated using Real-time PCR and IFN-γ serum level was quantified using ELISA technique. SPSS (version: 20), analysis of Covariance (ANCOVA) was used for statistical analysis.
Results:
PCR results confirmed that all 10 isolates were L. major. The mean of IL-12 gene expression in vitro, in vivo and IFN-γ serum levels (pg/ml) after 2 and 3 weeks treatment in vivo, increased significantly following the treatment with Glucantime in the two groups of Balb/c mice infected either with patients' isolates or standard L. major. No significant difference was seen between the patients' isolates and standard species.
Conclusions:
Although the L. major were isolated from patients with active lesion and no clinical response to Glucantime after at least one courses of Glucantime treatment but in vivo and in vitro immune response of L. major isolates showed no difference between the patients' isolates and standard L. major.
... Carbopol 971 P has lower level of crosslinking density than Carbopol 934P and Carbopol 974P. 9 The purpose of this study was to design a buccal drug delivery system using Lidocaine and a buccal adhesive and to evaluate the feasibility of a sustained transbuccal drug delivery system. Inflammatory processes cause most oral cavity diseases. ...
The present study was intended to develop a new oral mucosal dosage form with a view of solving problems of the topical administration of Lidocaine, a local anesthetic drug, in the oral cavity. The drug was formulated as sustained release mucoadhesive bilayered tablets using mucoadhesive polymers. The first layer, consisting of a drug impermeable backing, was prepared by compression of Kollidon SR, Mg-stearate, Aerosil and talc blend in a hydrolic press at 5 ton pressure for 5 seconds. The second layer, responsible for buccal drug delivery and tablet retention on the mucosa was obtained by compression of a mixture of drug, mucoadhesive polymer and cellulose derivative for 1 min at 5 ton pressure. The tablets were evaluated in terms of swelling and water uptake and in vivo mucoadhesive performance was performed with nonmedicated tablets. In vitro drug release studies were also carried out containing fixed amount of Lidocaine (50mg), different concentrations of mucoadhesive polymer (Carbopol 934P) and hydroxypropyl methyl cellulose (HPMC). Drug release was only 30.9% in 6 hours when Carbopol 934P was used alone and at a higher concentration (240mg). Release was faster when lower concentration of polymer was used. When used in combination with HPMC, drug release was slower. In vivo mucoadhesive performance with nonmedicated tablets showed very good adherence to buccal mucosa for 6 hours and no signs of irritation was reported. Moreover, it adheres well to the gum, is not washed away by salivary fluid and is simple to apply, which indicates a better patient compliance.
... For this reason, dosage forms that incorporate such low solubility drugs provide a major challenge for sustained release technologists. [3,4] . Carbopol polymers are pH sensitive, [5,6] environmentally responsive polymer or considered as smart gels [7] . ...
Till now very few formulations are available from which the drug is absorbed uniformly so that safe and effective blood level of Norfloxacin could be maintained for a prolonged period. To fulfill this requirement a controlled release mucoadhesive suspension was prepared using mucoadhesive polymers. The chemical interaction between Norfloxacin and different polymers in suspensions has been studied to know their compatibility by Fourier Transform Infrared Spectroscopy (FTIR). Ultrasonication method was used for the preparation of different formulations, taking Carbopol934, Carbopol940 and Hydroxypropyl methyl cellulose polymers. FTIR (400 cm-1 to 4000 cm-1 region) Spectroscopic study was carried out and its spectra were used for interpretation. From the spectral interpretation, it was found that in formulations, the carboxylic groups of Norfloxacin and hydroxyl groups of respective polymers encountered chemical interaction leading to esterification and hydrogen bonding (both intermolecular and polymeric). It may be concluded that Norfloxacin is compatible with three polymers used. Formation of micellies due to esterification and intermolecular hydrogen bonding causes more drug entrapment. In addition, stable suspensions are formed without hampering the C-F bond of the quinolone nucleus, which is responsible for the antibacterial activity of the drug. As a result, stable mucoadhesive suspensions of Norfloxacin could be produced and hence, these polymers may be considered as effective carriers for Norfloxacin.
... Carbopol 934 (C934) and Carbopol 940 (C940) are mucoadhesive, biodegradable and environmentally responsive Carbopol polymers and are considered as 'smart gels' [9,10]. Both consist of chains of polyacrylic acid but differ in the cross linking agents used in their production which are allyl ethers of sucrose (allylsucrose) and pentaerythritol (allylpentaerythritol), respectively [11,12]. They have recently attracted considerable interest in the field of drug delivery as a means of providing an on-off release by shrinking and swelling in response to change in pH [13,14]. ...
Purpose: To evaluate physicochemical changes in ciprofloxacin following incorporation in Carbopol polymeric composites. Methods: The ciprofloxacin and Carbopol were mixed in water in a drug:polymer ratio of 1:5 (w/w) and homogenized to produce uniform composites. X-ray powder diffraction analysis of the pure ciprofloxacin and the Carbopol polymeric composites of the drug were obtained using a powder diffractometer. Spectra for the materials were also generated by Fourier transform infrared (FTIR) spectroscope interfaced with an infrared (IR) microscope operated in reflectance mode. Results: Based on the Hanawalt system, three prominent x-ray diffractogram (XRD) peaks of the pure ciprofloxacin and the drug in the polymeric composites exhibited d-spacing at similar 2 θ values, but the relative intensity of these peaks was higher in the polymeric composites. FTIR analysis indicates that there were intermolecular hydrogen bonding and esterification between the drug and polymer in the polymeric composites. Conclusion: The changes that occurred in ciprofloxacin indicate increase in stability, decrease in solubility and delayed release of the drug from polymeric composites which could facilitate the formulation of a sustained release form of the drug. © Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria. All rights reserved.
... The prolonged contact time has been attributed to rheological properties of formulation, which delays its clearance from the mucosa 4 . In the present study, the polymer used is Carbopol940 (C940), which consists of chains of polyacrylic acid 5 (Fig. 2). ...
... Carbopol is a commonly used gelling agent that rarely causes adverse reactions when utilized topically (37). Its safety for both internal and external administration has been determined following thorough toxicological studies (37,38). It is composed of cross-linked carbomer polymers that form a microgel structure. ...
Peripheral opioid receptor targeting has been well established as a novel target in clinical pain management for acute and chronic peripheral inflammatory pain. The physiochemical properties of the peripheral mu-opioid receptor agonist, loperamide HCl, limit the use of the free drug as an analgesic or anti-inflammatory agent, particularly for dermal delivery across intact skin.
Our objective was to manufacture an effective topical formulation containing loperamide using liposomal delivery that would allow loperamide to produce analgesia and anti-inflammatory effects, by penetrating the epidermis to reach peripheral opioid receptors within the dermis of intact skin.
A randomized, double blind, controlled animal trial.
Thirty-five adult male Wistar rats (200 - 250 g) were randomly divided into 5 groups: loperamide HCl-encapsulated liposomal gel, naloxone methiodide + loperamide HCl-encapsulated liposomal gel, free loperamide gel, empty liposomal gel, and 1% diclofenac gel (Voltaren®). Diclofenac gel was used as a positive control as it is clinically used as a topical analgesic and anti-inflammatory drug. Animals received an intraplantar injection of 150 μl Complete Freund's Adjuvant (CFA) into the right hindpaw and experiments were performed 5 days post-CFA injection, which corresponded to the peak inflammatory response. All manufactured formulations were applied topically on both hind paws twice daily, whereas Voltaren gel was applied 3 times a day in accordance with the manufacturer's instructions. The dose administered was 50 μl, which equated to 0.4 mg of loperamide HCl for the loperamide HCl treatment groups (low dose). Naloxone methiodide (1 mg/kg) was administered via intraplantar injection, 15 minutes prior to application of loperamide HCl-encapsulated liposomal gel to determine opioid receptor dependent activity. An investigator blinded to the treatment administered assessed time course of the antinociceptive and anti-inflammatory effects using a paw pressure analgesiometer and plethysmometer, respectively.
Application of loperamide HCl in a liposomal gel formulation exerted analgesic and anti-inflammatory effects exclusively in peripheral painful inflamed tissue. This formulation produced highly significant analgesic and anti-inflammatory effects over the 48-hour time course studied following topical administration in rats with CFA-induced inflammation of the paw. As expected, the diclofenac gel group showed significant antinociception over the duration of the study; however, this effect was lower in comparison to the loperamide HCl liposomal gel formulation. All other control groups showed no significant antinociceptive effects. In addition, all control groups (1% diclofenac gel, free loperamide gel, and empty liposomal gel) did not demonstrate a significant change in paw volume over 48 hours.
In vivo studies were performed in the well-established rodent model of acute inflammatory pain. We are currently studying this approach in chronic pain models known to have clinical activation of the peripheral immune-derived opioid response.
The study demonstrates that topically applied loperamide encapsulated within liposomal systems has improved therapeutic efficacy over conventional formulations for the local treatment of acute peripheral inflammatory pain conditions where the skin has remained intact. Once in the inflamed peripheral tissue, loperamide provides analgesic and anti-inflammatory effects in a similar manner to peripheral endogenous opioids. This preparation optimises the retention of drug at the site where action is required.
... In the present study design, the polymer used is Carbopol934 (C934) which consists of chains of polyacrylic acid 10 (Fig. 2). Carbopol polymers form hydrogel that change their swelling behavior upon exposure to an external stimulus such as change in pH 11,12 , temperature 13 , light, or electric field, and are known as "environmentally responsive polymers" or "smart gels" 14,15 . ...
Purpose: Ciprofloxacin, an antibacterial agent, is having low solubility in aqueous solution and high rate of absorption from the stomach. It is precipitated at alkaline pH which leads to erratic absorption of the drug from small intestine. To overcome these difficulties, many researchers have prepared different formulations of Ciprofloxacin. But till now very few formulations are available from which the drug is absorbed uniformly, so that safe and effective blood level of Ciprofloxacin can be maintained for a prolonged period. To fulfill this requirement, in the present study, a sustained release drug delivery system (hydrogel) has been designed and chemical interaction between Ciprofloxacin and polymer in hydrogel has been studied by FTIR and Raman Spectroscopy. Methods: Ultrasonication method was used for preparation of hydrogel of the Ciprofloxacin, taking Carbopol 934 polymer with drug to polymer weight ratio 1:5. FTIR (400 cm -1 to 4000 cm -1 region) and Raman (140 to 2400 cm -1 region) Spectroscopic studies were carried out and spectra were used for interpretation. Results: From the spectral interpretation, it has been found that in hydrogel, the carboxylic groups of Ciprofloxacin and hydroxyl groups of Carbopol934 undergo chemical interaction leading to esterification and hydrogen bonding (both intermolecular and polymeric). Conclusions: The formation of micelles due to esterification and hydrogen bonding causes more drug entrapment and formation of a stable hydrogel, as a result of which, the hydrogel of Ciprofloxacin gives better controlled release and mucoadhesive action in the gastrointestinal tract and hence Carbopol934 can be considered as an effective carrier of Ciprofloxacin.
... [14] In this study design, the polymer used is carbopol934 (C934) which consists of chains of polyacrylic acid [ Figure 2]. [15] The hydrophilic polymers may form a complex with the low solubility drug-like norfloxacin. ...
Till now very few formulations are available from which the drug is uniformly absorbed, so that the safe and effective blood level of norfloxacin could be maintained for a prolonged period. To fulfill this requirement, a controlled release mucoadhesive suspension was prepared by using a mucoadhesive carbopol934 polymer. The chemical interaction between norfloxacin and the polymer in formulation (prepared by an ultrasonication method) has been studied by FTIR and Raman spectroscopy. From the spectral interpretation, it has been found that in formulation, the carboxylic groups of norfloxacin and hydroxyl groups of carbopol934 undergo chemical interaction, leading to esterification and hydrogen bonding. The formation of micellies due to esterification and hydrogen bonding causes more drug entrapment and a stable formulation. From this it can be concluded that the formulation of norfloxacin may give a better controlled release and mucoadhesive action in the gastrointestinal tract. Hence, carbopol934 could be considered as an effective carrier for norfloxacin.
... cross-linked with the polyalkenyl ethers or divinyl glycol providing carboxyl groups by the acrylic acid backbone [57]. In addition, the charge neutralization may be benefit for the loaded cationic niosomes in Carbopol gel to have better physical stability [58]. ...
The 20mM cationic niosomes composed of Tween61/cholesterol/CTAB at 1:1:0.5M ratio which gave the best physical appearance, particle size, zeta potential and in vitro cytotoxicity were selected from six cationic niosomes prepared from various cationic lipids. The selected cationic niosomes were loaded with the semi-purified fraction 3 of Oryza sativa (OSF3) which gave the highest in vitro 5α-reductase inhibition activity. The physicochemical characteristics as well as transfollicular penetration through porcine skin by Franz diffusion cells of gel OSF3 niosomes, OSF3 niosomes, gel OSF3 and OSF3 solution were investigated. Gel containing niosomes loaded with OSF3 exhibited physical stability with 77.68% of gamma-linolenic acid, 85.34% of linoleic acid and 89.47% of oleic acid remaining for 3 months at 25 °C. In the skin, the OSF3 niosomes (120.27 ng/cm(2)) and gel OSF3 niosomes (118.17 ng/cm(2)) showed the highest cumulative amounts of the total unsaturated fatty acids (gamma-linolenic acid, linoleic acid and oleic acid) in comparing to those from the gel OSF3 (15.34 ng/cm(2)) and OSF3 solution (20.31 ng/cm(2)) of about 8 and 6 times, respectively. In the receiver compartment, the gel OSF3 niosomes (6.27 ng/cm(2)) exhibited lower cumulative amount of the total unsaturated fatty acids than that of the OSF3 niosomes (11.20 ng/cm(2)) of about 2 times. This study has suggested that gel containing OSF3 loaded in niosomes appeared to be the suitable system for topical anti-androgenic alopecia application because of the convenient use and high transfollicular penetration in the skin, but not in the receiving compartment with the advantage of low systemic effect.
... These findings are contrary to those observed in previous studies [21] which have shown that the addition of C974P to formulations produced tablets of high mechanical strength, low friability and improved viscosity. DSC studies conducted on the formulations comprising ternary system consisting of gelatin, mannitol and carbopol resulted in a reduction in the glass transition temperature (À31.7 ± 0.7°C with the polymer and À27.5 ± 0.1°C without the polymer) ( Fig. 14 and Table 5). ...
Despite recent success, many fast-disintegrating tablets (FDTs) still face problems of low mechanical strength, poor mouth-feel and higher disintegration times. This study aimed to optimise FDTs using a progressive three-stage approach. A series of hardness, fracturability and disintegration time tests were performed on the formulations at each stage. During Stage I, tablets were prepared in concentrations between 2% and 5% w/w, and were formulated at each concentration as single and combination bloom strength gelatin (BSG) using 75 and 225 BSGs. Analysis revealed that both hardness and disintegration time increased with an increase in gelatin concentration. A combination (5% gelatin) FDT comprising a 50:50 ratio of 75:225 BSGs (hardness: 13.7 ± 0.9 N and disintegration time: 24.1 ± 0.6 s) was judged the most ideal, and was carried forward to Stage II: the addition of the saccharides sorbitol, mannitol and sucrose in concentrations between 10% and 80% w/w. The best properties were exhibited by mannitol-containing formulations (50%-hardness: 30.9 ± 2.8 N and disintegration time: 13.3 ± 2.1 s), which were carried forward to the next stage: the addition of viscosity-modifying polymers to improve mouth-feel and aid pre-gastric retention. Addition of carbopol 974P-NF resulted in the enhancement of viscosity with a compromise of the hardness of the tablet, whereas Pluronic F127 (6%) showed an increase in disintegration time and viscosity with retention of mechanical properties.
... [4,5] It consists of chains of polyacrylic acid having cross linking agent, allyl ethers of sucrose (allylsucrose) [ Figure 2]. [6,7] It has recently attracted considerable interest in the field of drug delivery as a means of providing an on-off release by shrinking and swelling in response to change in pH. [8,9] The polymer can protect a drug from its physiological environment by improving its stability in vivo. ...
Mucoadhesive polymeric (carbopol 934) suspension of ciprofloxacin was prepared by ultrasonication and optimized with the aim of developing an oral controlled release gastro-retentive dosage form. The qualitative analysis of the formulation was performed by fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray powder diffraction (XRD), and scanning electron microscopy (SEM) analyses. FTIR (400 cm(-1) to 4000 cm(-1) region) and Raman (140 to 2400 cm(-1) region) Spectroscopic studies were carried out and the spectra were used for interpretation. XRD data of pure drug, polymer and the formulation were obtained using a powder diffractometer scanned from a Bragg's angle (2θ) of 10° to 70°. The dispersion of the particle was observed using SEM techniques. The particle size distribution and aspect ratio of particles in the polymeric suspension were obtained from SEM image analysis. The results from FTIR and Raman spectroscopic analyses suggested that, in formulation, the carboxylic groups of ciprofloxacin and hydroxyl groups of C934 undergo a chemical interaction leading to esterification and hydrogen bonding. The XRD data suggested that the retention of crystalline nature of ciprofloxacin in the formulation would lead to increase in stability and drug loading; decrease in solubility; and delay in release of the drug from polymeric suspension with better bioavailability and penetration capacity. The SEM image analysis indicated that, in the formulation maximum particles were having aspect ratio from 2 to 4 and standard deviation was very less which provided supporting evidences for homogeneous, uniformly dispersed, stable controlled release ciprofloxacin suspension which would be pharmaceutically acceptable.
... It has been observed that carbopol (carboxypolymethlene polymer), which is present in most carbamide peroxide bleaching gels to provide thickness, is able to decrease enamel microhardness after carbamide peroxide bleaching at a neutral pH (Basting et al. 2005). Carboxypolymethylene is an acidic vinyl polymer with active carboxyl groups and dissociates in the presence of water, resulting in a pH close to 3.0 (Hosmani 2006). The low pH of carbopol could explain dentine demineralization of CP bleached specimens. ...
To evaluate the effects of intracoronal bleaching on ultimate tensile strength (UTS) of sound and etched dentine and its ultrastructure morphology.
Bovine dentine specimens with (e) or without previous etching with 37% phosphoric acid for 15 s were used for the intracoronal bleaching experiments. Teeth were randomly assigned to five treatments (n = 10): (C) control--no bleaching, (SP) sodium perborate, (CP) 35% carbamide peroxide, (25% HP) 25% hydrogen peroxide and (35% HP) 35% hydrogen peroxide. Bleaching was performed four times within a 72 h interval and afterwards, dentine pulp chamber blocks were obtained. The blocks were sectioned in 0.7 mm-thick slices and these were trimmed to reduce the inner dentine to a dumbbell shape with a cross-sectional area of 0.8 mm(2). Specimens were tested with the microtensile method (0.5 mm min(-1)) and data were analysed (two-way ANOVA-Tukey test, P < 0.05). Additional teeth were prepared for transmission electron microscopy (TEM) to evaluate dentine ultramorphology.
The mean values of the UTS (SD) in MPa for sound dentine were: C = 48.3(8.5)a, SP = 34.6 (8.2)b, CP = 32.9 (8.9)b, 25% HP = 28.0(4.6)b, 35% HP = 26.4(6.6)b, and pre-etched dentine: Ce = 38.9(13.8)a, SPe = 31.3 (9.3)ab, CPe = 28.4 (6.2)ab, 25% HPe = 30.0 (7.9)ab, 35% HPe = 19.9(4.6)b. Significant differences between the means are indicated by the letters. TEM observations exhibited demineralization areas for all bleaching treatments.
Bleaching decreased dentine UTS after treatment. Pre-etched not-bleached dentine (Ce) presented UTS similar to pre-etched bleached dentine, except for 35% HPe. The decrease of UTS of bleached dentine could be attributed to ultrastructural alterations such as loss of inorganic components.
... This polymer is highly swellable in aqueous environments and has absorption-enhancing properties possibly due to its strong mucoadhesive properties. [15] Swellable monolithic matrix systems are usually manufactured by direct compression of a mixture of the drug and a hydrophilic polymer. When these drug delivery systems come into contact with a thermodynamically compatible solvent, relaxation of polymeric chain takes place. ...
The in vitro performance of monolithic matrix systems containing the interpolyelectrolyte complex between chitosan and polycarbophil as excipient was evaluated in terms of their swelling, bioadhesive, and drug release properties. The different matrix systems showed excellent swelling properties without erosion, except for the formulation containing the highest quantity chitosan-polycarbophil complex that exhibited surface erosion in addition to swelling. All the different matrix systems exhibited significantly higher bioadhesive properties than the control group. Furthermore, they showed controlled insulin release without an initial burst release effect. However, only the matrix system that exhibited surface erosion in combination with swelling approached zero-order release.
The current article mainly highlights the mucoadhesive drug delivery with merits like the prolonged holding timeat the action site and also provides a controlled rate of drug release for improved therapeutic outcomes. Moreover, mucosal delivery can eliminate problems of the conventional oral route, such as first pass metabolism as well as acid degradation. However, the eye has unique anatomy and physiology that can cause hindrance and challenges in comparison to the other organs of the body. Additionally, conventional delivery vehicles like solutions, suspensions, and ointments have many demerits such as rapid precorneal clearance, subject variability, drainage, and uncontrolled releasefrom the dosage form. Therefore, novel pharmaceutical ophthalmic formulationslike gels, nanosuspensions, nano-particles, liposomes, microemulsions, iontophoretic dosage forms, and ocusertswere tried and tested in the past few years for ophthalmic delivery. These novel delivery products provideenhanced solubility and bioavailability in a controlled manner to overcome conventional demerits. Here in this review, we have summarized the improvement of drug studies thatare currently underway for eye drug carriers along with stages and important aspects of novel drug delivery to the eye.
O presente trabalho teve como objetivo realizar o estudo de possíveis bases para formulação de gel higienizante bucal de cães, prevenindo assim periodontite, gengivite e outros possíveis problemas bucais. A metodologia do trabalho foi por meio de revisão bibliográfica para verificar quais os principais tipos de Carbopol® utilizados no desenvolvimento de géis para a formulação, principais características físico-químicas do Carbopol® presença ou não de resíduos de benzeno na fabricação dos polímeros, preocupando-se e verificando os principais problemas de saúde do uso de produtos com presença de benzeno, independentemente da quantidade. Verificou-se os principais produtos em formulações de géis para limpeza, e por fim, após a análise dos dados obtidos realizou-se uma sugestão de uma formulação de gel para limpeza bucal de cães, com eficácia e sem riscos à saúde com o uso prolongado.
Pluronic F127® was associated with a carbomer homopolymer type B, as a model polymer blend to evidence the information provided by rheological and mechanical analyses on the development of bioadhesive thermoresponsive systems. The mechanical analysis enabled to observe that 20% (w/w) Pluronic F127®-polymer blends were harder, more adhesive, more mucoadhesive, more compressive and less soft. In addition, continuous flow rheometry demonstrated that the systems were plastic with rheopexy (15%, w/w, Pluronic F127®) or thixotropic (20%, w/w, Pluronic F127®). Oscillatory rheometry exhibited the increase of temperature, and the polymeric concentration increases the elasticity of the formulations. Moreover, correlation index showed that softness and textural analysis can be correlated and complementary, whereas adhesiveness cannot be correlated to mucoadhesion and is less specific. Rheological interaction parameter and gelation temperature showed that 15/0.25-polymer blend is suitable for pharmaceutical and biomedical application, since it can be administered in the liquid form and be gelled in the application site with proper mucoadhesion that can suggest an improved clinical efficacy. Therefore, the mechanical and rheological analyses are useful to characterize and select the best bioadhesive thermoresponsive formulation for the proposed treatment with improved performance.
Poly (vinyl pyrrolidone) (PVP)/ Carbopol 934 (CPL) blend microspheres were prepared through W/O emulsion-solvent diffusion method using ethanol as solvent. Flutamide (FLT), an anti Cancer drug, was encapsulated in PVP/CPL microspheres for drug release studies. Morphology, size, encapsulation efficiency and drug release from these microspheres were evaluated. Drug loaded microspheres were analyzed by Fourier transform infrared spectroscopy (FTIR), to undrstand the chemical interactions and formation of IPN blend structures. Differential Scanning Calorimetry (DSC) measurements on drug-loaded microspheres confirmed the molecular level dispersion of Flutamide in the microspheres. Scanning electron microscopy (SEM) confirmed the spherical nature and smooth surface of the microspheres produced. X-ray diffraction studies (X-RD) was performed to understand the crystalline nature of drug after encapsulation into these microspheres. In-vitro release studies indicated a dependence of release rate on the extent of cross linking, amount of drug loading and the amount of PVP, but slow release rates was extended up to 14 h.
Bioadhesive systems present the ability to get in close contact with the biologic substrate. When the biological surface is the mucosal tissue, the system is called mucoadhesive. Thermoresponsive systems display a significant physicochemical change in response to the temperature modifications. The development of blends composed by bioadhesive thermoresponsive polymers provides new nanostructured therapeutic systems. The Mucoadhesive Thermoresponsive Systems (MTS) can offer easy administration with no irritancy, improve adhesion, which provides increased availability, the contact time, the controlled release, and protection of the active agent, and consequently, major patient adherence to the therapeutics. The MTS are designed to delivery active agents to different mucous, such as buccal, ocular, nasal, vaginal, and colorectal. These polymeric blends can be composed by poloxamer 407 (P407) and carbomers (Carbopol 934P, Carbopol 971P, Carbopol 974P), polycarbophil, chitosan, alginates, guar gum, carrageenan, and polymers derived from cellulose. Therefore, in this chapter, we have assessed and discussed the importance, applications, and perspectives of this novel approach as potentially useful therapeutic modality.
Polycarbophil is widely used in a variety of pharmaceutical formulations, mainly for their strong ability to adhere to the epithelial and mucous barriers (bio/mucoadhesion). On the other hand, its association with the thermoresponsive polymer (poloxamer 407) has been poorly explored. This work investigates the rheological, mechanical and mucoadhesive properties of polymer blends containing polycarbophil and poloxamer 407, in order to select the best formulations for biomedical and pharmaceutical applications. Mechanical (hardness, compressibility, adhesiveness, softness, and mucoadhesion) and rheological characteristics (consistency index, yield value and hysteresis area) showed that 20% (w/w) poloxamer 407- polymer blends exhibited higher values parameters. However, the rheological interaction parameter, which was more sensible than the mechanical interaction parameter, revealed higher synergism for systems comprising 15% (w/w) poloxamer 407, due to the system organization and polymers' properties. Furthermore, gelation temperatures were appropriated, suggesting that polymer blends can be used as biomedical materials, and displaying easy administration, enhanced retention and prolonged residence time at the site of application. Therefore, rheological, mechanical and mucoadhesive characterization provided a rational basis for selecting appropriated systems, useful for mucoadhesive drug delivery systems and biomedical applications.
The development of binary polymeric mixtures (polymer blends) containing bioadhesive and thermoresponsive polymers can provide new materials for biomedical applications, with higher contact, increased adhesion, prolonged residence time, protection, and in determined cases, secured absorption of an active agent from the site of application. Mixtures were prepared using a wide range of poloxamer 407 and Carbopol 971P(®) amounts. The rheological (flow and oscillatory), sol-gel transition temperature, mechanical (hardness, compressibility, adhesiveness, cohesiveness and elasticity), softness, and mucoadhesive properties of formulations were investigated. Moreover, the interaction between the different proportions of polymers was also analyzed. Continuous shear and oscillatory rheometry identified the plastic flow with various degrees of thixotropy, besides the viscoelastic behavior of formulations. The determination of gelation temperature displayed values ranged from 27.17 to 41.09°C. It was also found that low carbomer concentrations were enough to provide positive interaction parameter. However, the highest values were obtained for the polymeric blends with higher concentration of poloxamer 407. The mucoadhesion and softness index were greater in preparations containing 20% (w/w) poloxamer 407. The rheological, mechanical and mucoadhesive properties of the polymeric blends can be manipulated by changing the concentrations of the polymers and they suggest the blends are worthy of biomedical applications.
Viscoplastic fluids behave like solids below a critical applied stress and flow like mobile liquids at higher stresses. They are typically composed of colloidal or nanoscale constituents, and they are prevalent in consumer products, coatings and paints, industrial fluids, foods, mineral wastes, etc. This review discusses the flow of viscoplastic fluids in systems containing several fluids separated by interfaces. Such systems include, for example, multilayer flows, films, jets, bubbles and drops and are encountered in most of applications. We review the current state of experiments, simulations and theory of viscoplastic flows in the presence of the interfaces.
The experimental results for medicinal drug Fibril-SF were carried out with the help of Biomedical medical optical spectroscopic techniques such as UV/Visible, FTIR,FT-Raman. The spectral analysis indicated that the specific functional groups of the drug materials have almost the same chemical characteristics like its molecular formula. The chemical compounds such as N=C=O, -N=C=S,-N=C=N-,-N 3 ,C-C,C-H,C=C,S-H,S-N,CH 3 and CH 2 are present.
The purpose of the study was to prepare a stable 6% Flurbiprofen hydrogel. Oral Flurbiprofen generates several side effects; hence hydrogel was prepared to reduce these side effects in the present study. Gastrointestinal side effects such as bleeding, ulceration, and perforation of the stomach or intestines are commonly seen when the drug is administered orally. In this research, a hydrogel was formulated whereby flurbiprofen was the active ingredient, using a thickening agent (Carbapol) and distilled water (solvent). The finished formulation gives a white color hydrogel. Stability studies were performed at different accelerated conditions, i.e. 2-40C (Cool room), 250C (Room temperature) and 400C (Oven) for 28 days to predict the stability of formulations. Different parameters, namely pH, liquefaction, color, phase separation and effect of centrifugation (Simulating gravity) were determined during stability studies. There were no changes in liquefaction, color, phase separation and centrifugation in the formulation stored at 2-40C (Cool room), 250C (Room temperature) and 400C (Oven) up to 28 days. Based on one-way ANOVA test, the changes in pH values of the sample was not significant at different levels of time and temperature (p > 0.05). The mean pH value of the sample at different storage conditions was not far from the initial value of the studies, which is pH 5.5. The drug content of Flurbiprofen hydrogel was found to be 76.3% of Flurbiprofen. The Hydrogel released 79.46% of the drug content by 8 hours. Overall, this indicates that the formulation was stable and can be used for the topical dosage form.
Keywords: Hydrogel, Flurbiprofen, Carbapol, Distilled water and Stability.
The purpose of the study was to prepare a stable 6% Flurbiprofen hydrogel. Oral Flurbiprofen generates several side effects; hence hydrogel was prepared to reduce these side effects in the present study. Gastrointestinal side effects such as bleeding, ulceration, and perforation of the stomach or intestines are commonly seen when the drug is administered orally. In this research, a hydrogel was formulated whereby flurbiprofen was the active ingredient, using a thickening agent (Carbopol) and distilled water (solvent). The finished formulation gives a white color hydrogel. Stability studies were performed at different accelerated conditions, i.e. 2-40 o C (Cool room), 250C (Room temperature) and 400C (Oven) for 28 days to predict the stability of formulations. Different parameters, namely pH, liquefaction, color, phase separation and effect of centrifugation (Simulating gravity) were determined during stability studies. There were no changes in liquefaction, color, phase separation and centrifugation in the formulation stored at 2-40 o C (Cool room), 250 o C (Room temperature) and 400 o C (Oven) up to 28 days. Based on one-way ANOVA test, the changes in pH values of the sample was not significant at different levels of time and temperature (p > 0.05). The mean pH value of the sample at different storage conditions was not far from the initial value of the studies, which is pH 5.5. The drug content of Flurbiprofen hydrogel was found to be 76.3% of Flurbiprofen. The Hydrogel released 79.46% of the drug content by 8 hours. Overall, this indicates that the formulation was stable and can be used for the topical dosage form.
To report the observation of prolonged reepithelialization after photorefractive keratectomy (PRK) associated with the use of besifloxacin 0.6% (Besivance; Bausch & Lomb, Rochester, NY) underneath bandage contact lenses (BCLs) placed during surgery.
An office-based private practice and retrospective chart review. The healing parameters examined included epithelial healing time, haze formation, discomfort, and visual recovery of 4 patients (7 eyes) treated with besifloxacin 0.6% under BCLs placed after the PRK was performed.
All the eyes had delayed epithelial closure (mean, 8.8 days; range 5-13 days). All the patients experienced a delayed visual recovery and significant pain after the surgery, and 2 of 4 patients experienced recurrent corneal erosions for weeks to months after they underwent the PRK. All but 1 eye developed corneal haze persisting for 1 year or more after the surgery. Only 1 eye among the 7 eyes treated with besifloxacin 0.6% under the BCL had 20/20 or better uncorrected visual acuity 3 months postoperatively.
All the patients treated with besifloxacin 0.6% on the stromal bed exhibited significant problems with corneal epithelial healing and delayed visual recovery. We caution the use of besifloxacin 0.6% underneath a BCL during a PRK or other ocular surface surgeries requiring corneal epithelial debridement.
The effects of polymer addition on the rheological parameters of sodium bentonite water dispersions at ambient conditions were studied using high molecular mass carboxymethylcellulose (CMC) and Carbopol 980. Adsorption isotherms using the batch equilibrium technique of the polymers onto the bentonite particles were Langmuir isotherms of the L1 type, indicating monolayer adsorption of the polymers onto the surface of the bentonite particles. The aqueous dispersions of 3% and 4% sodium bentonite exhibited Herschel–Bulkley rheological behavior. Addition of CMC up to 1.5% by mass to the 3% sodium bentonite dispersions decreased the yield stress and the flow consistency index because of the steric effects caused by the adsorption of the polymer. This state was then followed by a plateau of the yield stress and a considerable increase of the flow consistency index, indicating that after a particular polymer concentration, further addition merely increased the liquid viscosity of the mixture. The flow behavior index was not affected by CMC addition. Addition of Carbopol 980 to the 3% and 4% sodium bentonite dispersions up to 0.15% by mass again firstly decreased the yield stress and the flow consistency index, then increased the yield stress and the flow consistency index with increasing polymer concentration. The high shear viscosity of bentonite–Carbopol dispersions showed also a minimum followed by a drastic increase. The flow behavior index was not affected significantly by the polymer addition.
The aim of present work was to prepare mucoadhesive microspheres containing Clarithromycin, an anti- H. pylori agent, used for treatment of peptic ulcers. Mucoadhesive microspheres were prepared by "Calcium induced ionotropic gelation" method. Sodium alginate was used as encapsulating agent and carbopol 934 P & polycarbophil were used as bioadhesive polymer. A 3 2 - full factorial design was employed taking concentration of carbomer and sodium alginate as independent variables. The evaluation parameters included encapsulation efficiency, in vitro mucoadhesion, swelling study, in vitro release study. Microspheres were discrete, spherical and free flowing. Swelling index was ranging from 1.2 to 2, indicating excellent swelling property. The microspheres exhibited excellent mucoadhesive property and good drug entrapment. Formulations showed polymer concentration dependent drug release over a period of 12 hrs. Microspheres were having good mucoadhesive property with good encapsulation capacity and a sustained release property.
Abstract Enhancement of transdermal absorption through rat skin and stability of the human tyrosinase plasmid (P) using Tat (T) and an entrapment in elastic cationic niosomes (E) were described. E (Tween61:cholesterol:DDAB at 1:1:0.5 molar ratio) were prepared by the freeze-dried empty liposomes (FDELs) method using 25% ethanol. TP was prepared by a simple mixing method. TPE was prepared by loading T and P in E at the T:P:E ratio of 0.5:1:160 w/w/w. For gel formulations, P, TP, PE and TPE were incorporated into Carbopol 980 gel (30 µg of plasmid per 1 g of gel). For the transdermal absorption studies, the highest cumulative amounts and fluxes of the plasmid in viable epidermis and dermis (VED) were observed from the TPE of 0.31 ± 0.04 µg/cm(2) and 1.86 ± 0.24 µg/cm(2)/h (TPE solution); and 4.29 ± 0.40 µg/cm(2) and 25.73 ± 2.40 µg/cm(2)/h (TPE gel), respectively. Only plasmid from the PE and TPE could be found in the receiving solution with the cumulative amounts and fluxes at 6 h of 0.07 ± 0.01 µg/cm(2) and 0.40 ± 0.08 µg/cm(2)/h (PE solution); 0.10 ± 0.01 µg/cm(2) and 0.60 ± 0.06 µg/cm(2)/h (TPE solution); 0.88 ± 0.03 µg/cm(2) and 5.30 ± 0.15 µg/cm(2)/h (PE gel); and 1.02 ± 0.05 µg/cm(2) and 6.13 ± 0.28 µg/cm(2)/h (TPE gel), respectively. In stability studies, the plasmid still remained at 4 ± 2 °C and 25 ± 2 °C of about 48.00-65.20% and 27.40-51.10% (solution); and 12.34-38.31% and 8.63-36.10% (gel), respectively, whereas at 45 ± 2 °C, almost all the plasmid was degraded. These studies indicated the high potential application of Tat and an entrapment in elastic cationic niosomes for the development of transdermal gene delivery system.
Micro-emulsions and sometimes nano-emulsions are well known candidates to deliver drugs locally. However, the poor rheological properties are marginally affecting their acceptance pharmaceutically. This work aimed to modify the poor flow properties of a nano-scaled emulsion comprising palm olein esters as the oil phase and ibuprofen as the active ingredient for topical delivery. Three Carbopol ® resins: 934, 940 and Ultrez 10, were utilized in various concentrations to achieve these goals. Moreover, phosphate buffer and triethanolamine solutions pH 7.4 were used as neutralizing agents to assess their effects on the gel-forming and swelling properties of Carbopol ® 940. The addition of these polymers caused the produced nano-scaled emulsion to show a dramatic droplets enlargement of the dispersed globules, increased intrinsic viscosity, consistent zeta potential and transparent-to-opaque change in appearance. These changes were relatively influenced by the type and the concentration of the resin used. Carbopol ® 940 and triethanolamine appeared to be superior in achieving the proposed tasks compared to other materials. The higher the pH of triethanolamine solution, the stronger the flow-modifying properties of Carbopol ® 940. Transmission electron microscopy confirmed the formation of a well-arranged gel network of Carbopol ® 940, which was the major cause for all realized changes. Later in vitro permeation studies showed a significant decrease in the drug penetration, thus further modification using 10% w/w menthol or limonene as permeation promoters was performed. This resulted in in vitro and in vivo pharmacodynamics properties that are comparably higher than the reference chosen for this study.
Rheological characteristics of gels were studied, with the focus on their use as a cosmetic base. Some ideal characteristics can be predicted by the rheological characterization, such as the performance, with easy application and without dripping or forming lumps and bubbles. Moreover, it is possible to detect signs of physical instability. The gels were prepared with sodium carboxymethyl cellulose 3% and 5%, with Carbopol 940 (INCI: Carbomer) and with Carbopol Ultrez (INCI: Acrylates/C10-30 alkyl acrylate crosspolymer). The tests performed were yield stress, stress sweep and creep and recovery. The gel with 3% of sodium carboxymethyl cellulose presented the most appropriated behavior and can be indicated as the most suitable cosmetic base.
The interaction of Newtonian drops of various volumes moving in yield stress material is investigated experimentally. Tetrachloroethylene
drops move in a rectangular reservoir filled with neutralized 0.07% w/w Carbopol gel under the action of gravity. For initially vertically aligned drop pairs, we present time evolution of separation
distance, velocities during the interaction and conditions for coalescence of the drops, which depend on the volumes of the
drops and the initial separation between them. For the asymmetric interaction of the pairs, we present interaction patterns,
which have been used for estimation of the size of the yielded region and its shape around the leading drop.
KeywordsFluid mechanics–Non-Newtonian fluids–Gels–Drop interaction–Yield stress–Carbopol solution
The aim of this project was to develop and optimize indomethacin microcapsules composed of multiple mucoadhesive polymers for high drug entrapment, good mucoadhesiveness and drug release in a controlled fashion over a longer period of time. Microcapsules containing sodium alginate, sodium carboxymethylcellulose, methylcellulose, Carbopol 934 and hydroxypropyl methylcellulose were prepared by orifice-ionic gelation method. The effects of composition of microcapsules on drug entrapment efficacy, drug release and mucoadhesive character were determined by mixture statistical design. Most formulations exhibited good mucoadhesive property in everted intestinal sac test. Drug entrapment efficiency (68-94%) was dependent on the type of polymers. Drug release (92-100%) extended over 12 h. The optimized formulation resulted in drug entrapment efficiency of 89.3%, drug release of 94.8% and mucoadhesiveness of 30.4%. All formulations were stable for more than 1.5 years. The optimized mucoadhesive microcapsules are promising for controlled delivery of indomethacin with twice a day oral administration.
The in vitro dissolution, swelling, and erosion behavior of monolithic matrix systems containing the well-known hydrophilic polymer, hydroxypropylmethylcellulose, and a combination of chitosan and polycarbophil in the form of an interpolyelectrolyte complex were compared in this study. The two different types of matrix systems showed both a combination of swelling and erosion as the drug release mechanism. Kinetic analysis of the in vitro release profiles of water-soluble drugs from the matrix tablets illustrated that those containing the chitosan-polycarbophil complex exhibited higher mean dissolution time values and therefore slower drug release compared with the other matrix systems. The analysis also indicated that zero-order release kinetics were approached for some of the formulations containing the chitosan-polycarbophil complex, while this could not be achieved for those containing hydroxypropylmethylcellulose.
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