Draize Test Research Articles

Estimation of the chemical-induced eye injury using a weight-of-evidence (WoE) battery of 21 artificial neural network (ANN) c-QSAR models (QSAR-21): Part I: Irritation potential

Evaluation of potential chemical-induced eye injury through irritation and corrosion is required to ensure occupational and consumer safety for industrial, household and cosmetic ingredient chemicals. The historical method for evaluating eye irritant and corrosion potential of chemicals is the rabbit Draize test. However, the Draize test is controversial and its use is diminishing - the EU 7th Amendment to the Cosmetic Directive (76/768/EEC) and recast Regulation now bans marketing of new cosmetics having animal testing of their ingredients and requires non-animal alternative tests for safety assessments. Thus, in silico and/or in vitro tests are advocated. QSAR models for eye irritation have been reported for several small (congeneric) data sets; however, large global models have not been described. This report describes FDA/CFSAN’s development of 21 ANN c-QSAR models (QSAR-21) to predict eye irritation using the ADMET Predictor™ program and a diverse training data set of 2928 chemicals. The 21 models had external (20% test set) and internal validation and average training/verification/test set statistics were: 88/88/85(%) sensitivity and 82/82/82(%) specificity, respectively. The new method utilized multiple artificial neural network (ANN) molecular descriptor selection functionalities to maximize the applicability domain of the battery. The eye irritation models will be used to provide information to fill the critical data gaps for the safety assessment of cosmetic ingredient chemicals.

An overview of current techniques for ocular toxicity testing.

Given the hazardous nature of many materials and substances, ocular toxicity testing is required to evaluate the dangers associated with these substances after their exposure to the eye. Historically, animal tests such as the Draize test were exclusively used to determine the level of ocular toxicity by applying a test substance to a live rabbit's eye and evaluating the biological response. In recent years, legislation in many developed countries has been introduced to try to reduce animal testing and promote alternative techniques. These techniques include ex vivo tests on deceased animal tissue, computational models that use algorithms to apply existing data to new chemicals and in vitro assays based on two dimensional (2D) and three dimensional (3D) cell culture models. Here we provide a comprehensive overview of the latest advances in ocular toxicity testing techniques, and discuss the regulatory framework used to evaluate their suitability.

Cutaneous Effects of Sea Buckthorn Oil Emulsion

Abstract Sea buckthorn oil (Hippophae rhamnoides L.) is medically used both externally and internally, but the external application is unsuitable due to its liquid, lipophilic and highly coloured nature. These difficulties could be overcome by a formulation of semisolid emulsion with sea buckthorn oil. Previous research on this formulation showed that it has higher wound healing potential than sea buckthorn oil, possessing an enhanced structure of liquid crystals, stability and suitability for topical use. The aim of this investigation was to completely characterizise a proposed emulsion by testing skin effects, such as moisturising potential, skin pH and potential to cause skin irritation. The emulsion was prepared by standard emulsifying techniques using a combination of surfactants that form an enhanced structure of liquid crystals. Approximately 40% of sea buckthorn oil was incorporated. The moisturising potential and skin pH were tested on the healthy skin of volunteers. Skin tolerance was tested on a rabbit skin model and evaluated by the Draize test. The tested emulsion containing sea buckthorn oil did not cause a significant change in skin pH, while it significantly increased skin hydration. Th ere was an absence of edema or erythema type of irritation after 2 h, 24 h, 48 h, 72 h and 7 days of application of the emulsion with sea buckthorn oil. The tested formulation shows good moisturizising effects and does not cause human or animal skin irritation. Th e study confi ms that the combination of the proposed ingredients in a sea buckthorn oil emulsion is adequate and could be safe for skin application

CUTANEOUS TOLERANCE OF SEA BUCKTHORN OIL EMULSION

Introduction: Sea buckthorn oil ( Hippophae rhamnoides L.) is medically used both externally and internally, but the external application is unsutable due to its liquid, lipophylic and highly colored nature. These difficulties could be overbriged by formulation of semisolid emulsion with sea buckthorn oil. Previous research on this formulation showed that it has higher wound healing potential then sea buckthorn oil, possesing enhanced structure of liquid crystals, stability and suitability for topical use. Aim: The aim of this investigation was to complete characterization of proposed emulsion, by testing its potential for causing skin irritation. Methods: The emulsion was prepared by standard emulsifying techniques using a combination of surfactants that form an enhanced structure of liquid crystals. Amount of 40% of sea buckthorn oil was incorporated. Since results of previous research on this formulation show wound healing effect on an animal model, we also tested skin tolerance of it on animal skin model. Evaluation was done by Draize test which measures level of skin changes of rabbit skin. Results: There was absence of edema or erythema type of irritation after 2h, 24h, 48h, 72h and 7 days of application of semisolid emuslion with sea buckthorn oil. Conclusion: This study confirmed that combination of the proposed ingredients is adequate and the concentrations of surfactants used to form stable emulsion were appropriate also for skin application. The proposed formulation of emulsion with sea buckthorn oil exerted percutaneous tolerance and could be safely applied on the skin. Key words: sea buckthorn oil, emulsion, topical use, irritation

Nanostructured lipid carrier surface modified with Eudragit RS 100 and its potential ophthalmic functions.

This study was carried out to evaluate the ocular performance of a cationic Eudragit (EDU) RS 100-coated nanostructured lipid carrier (NLC). The genistein encapsulated NLC (GEN-NLC) was produced using the melt-emulsification technique followed by surface absorption of EDU RS 100. The EDU RS 100 increased the surface zeta potential from −7.46 mV to +13.60 mV, by uniformly forming a spherical coating outside the NLC surface, as shown by transmission electron microscopy images. The EDU RS 100 on the NLC surface effectively improved the NLC stability by inhibiting particle size growth. The obtained EDU RS 100-GEN-NLC showed extended precorneal clearance and a 1.22-fold increase in AUC (area under the curve) compared with the bare NLC in a Gamma scintigraphic evaluation. The EDU RS 100 modification also significantly increased corneal penetration producing a 3.3-fold increase in apparent permeability coefficients (Papp) compared with references. Draize and cytotoxicity testing confirmed that the developed EDU RS 100-GEN-NLC was nonirritant to ocular tissues and nontoxic to corneal cells. These results indicate that the NLC surface modified by EDU RS 100 significantly improves the NLC properties and exhibits many advantages for ocular use.

Nanoemulsion gel-based topical delivery of an antifungal drug: in vitro activity and in vivo evaluation

Objective: In this study, attempt has been focused to prepare a nanoemulsion (NE) gel for topical delivery of amphotericin B (AmB) for enhanced as well as sustained skin permeation, in vitro antifungal activity and in vivo toxicity assessment.Materials and methods: A series of NE were prepared using sefsol-218 oil, Tween 80 and Transcutol-P by slow spontaneous titration method. Carbopol gel (0.5% w/w) was prepared containing 0.1% w/w AmB. Furthermore, NE gel (AmB-NE gel) was characterized for size, charge, pH, rheological behavior, drug release profile, skin permeability, hemolytic studies and ex vivo rat skin interaction with rat skin using differential scanning calorimeter. The drug permeability and skin irritation ability were examined with confocal laser scanning microscopy and Draize test, respectively. The in vitro antifungal activity was investigated against three fungal strains using the well agar diffusion method. Histopathological assessment was performed in rats to investigate their toxicological potential.Results and discussion: The AmB-NE gel (18.09 ± 0.6 µg/cm2/h) and NE (15.74 ± 0.4 µg/cm2/h) demonstrated the highest skin percutaneous permeation flux rate as compared to drug solution (4.59 ± 0.01 µg/cm2/h) suggesting better alternative to painful and nephrotoxic intravenous administration. Hemolytic and histopathological results revealed safe delivery of the drug. Based on combined results, NE and AmB-NE gel could be considered as an efficient, stable and safe carrier for enhanced and sustained topical delivery for AmB in local skin fungal infection.Conclusion: Topical delivery of AmB is suitable delivery system in NE gel carrier for skin fungal infection.

In vitro and in vivo topical delivery studies of tretinoin-loaded ultradeformable vesicles

IntroductionUltradeformable vesicles are highly promising tools to enhance the percutaneous transport of different drugs such as tretinoin across the skin barrier and also to increase the formulation stability at absorption site and reduce the drug induced irritation. MethodsTopical delivery of tretinoin-loaded ultradeformable vesicles (tretinoin–UDV) was evaluated concerning different studies, such as: the release and permeation profiles (tape stripping); skin penetration (fluorescence analysis); induced electrical changes in skin barrier properties; cytotoxicity (Trypan Blue assay) and skin irritation in in vivo conditions (Draize test). The novel formulation performance was also compared to a commercial tretinoin formulation regarding in vivo studies. ResultsIt was obtained a sustained and controlled drug release, as expected for UDV formulation. In addition, a dermal delivery was observed regarding the permeation study since it was not detected any drug amount in the receptor phase after 24h. Nile Red–UDV stained intensively mostly in the stratum corneum, corroborating the tape stripping results. Tretinoin–UDV decreased skin resistance, suggesting its ability to induce skin barrier disruption. Finally, the formulation vehicle (empty UDV) and tretinoin–UDV were not toxic under in vitro and in vivo conditions, at least, at 5×10−3mg/mL and 0.5mg/mL of tretinoin, respectively. ConclusionTretinoin−UDV is a promising delivery system for tretinoin dermal delivery without promoting skin irritation (unlike other commercial formulations), which is quite advantageous for therapeutic purpose.

Development, Characterization and in vivo Localization Study of Topical 5-Fluorouracil Gels: A Comparative Study with Conventional Formulation

5-Fluorouracil (5-FU) is one of the most effective antineoplastic agents used for the treatment of skin cancers and actinic keratosis (AK). Currently commercial formulation for topical 5-FU administration is available in the form of solution or cream. Commercial topical formulations are associated with the limitation of very short retention time at the administration site resulting in very poor skin permeation and deposition of drug. In the present study attempt was made for the preparation, optimization and characterization of bioadhesive gel formulations for localized delivery of 5-FU. Four bioadhesive gel formers, Carbopol 934, Carbopol 980, Methylcellulose (MC) and Poloxamer 188 were selected for the preparation of 5-FU bioadhesive gel formulations. The formulations were characterized for characteristic parameters including bioadhesive strength, skin deposition and interaction study. Carbopol 934 based bioadhesive gel formulation at the concentration of 1.5% w/w showed the best physicochemical properties such as viscosity (2670±12.2 cP), which was similar to the value obtained with the marketed cream (2870±14.4 cP), highest skin deposition (1290±56.4μg) and bioadhesive strength (18.62 gf). Cutaneous irritation of optimized bioadhesive gel formulations was also tested using the Draize test and only very slight erythema and no oedema was observed. In comparison, marketed formulation showed well defined erythema along with oedema formation. The result of the present study demonstrated that formulation of Carbopol 934 based 5-FU bioadhesive gel is a better alternative to the traditional cream base for enhanced topical delivery of 5-FU. The developed formulation will have the ease of application, better skin deposition and sustained release characteristic with reduced skin toxicity.

Engineering of polymer–surfactant nanoparticles of doxycycline hydrochloride for ocular drug delivery

Context: Physiologic barriers of the eye, short precorneal drug residence time and poor corneal penetration are the few reasons for reduced ocular bioavailability. Objective: This study was aimed to develop novel polymer–surfactant nanoparticles of hydrophilic drug doxycycline hydrochloride (DXY) to improve precorneal residence time and drug penetration. Materials and methods: Nanoparticles were formulated using emulsion cross-linking method and the formulation was optimized using factorial design. The prepared formulation was characterized for particle size, ζ potential, encapsulation efficiency, in vitro drug release and ex vivo drug diffusion studies. The antibacterial activity studies were also carried out against Escherichia coli and Staphylococcus aureus using the cup-plate method. In vivo eye irritation study was carried out by a modified Draize test in rabbits. Results and discussion: The particle size was found to be in the range of 331–850 nm. About 45–80% of the drug was found to be encapsulated in the nanoparticles. In vitro release demonstrated sustained release profile. Lower flux values in case of nanoparticles as compared to DXY pure drug solution in ex vivo diffusion studies confirmed the sustained release. The nanoparticles were found to be significantly effective (p < 0.001) than DXY aqueous solution due to sustained release of doxycycline from nanoparticles in both the E. coli and S. aureus strains. The formulation was found to be stable over entire stability period. Conclusion: The developed formulation is safe and suitable for sustained ocular drug delivery.

Cutaneous effects of sea buckthorn oil emulsion

Sea buckthorn oil (Hippophae rhamnoides L.) is medically used both externally and internally, but the external application is unsuitable due to its liquid, lipophilic and highly coloured nature. These difficulties could be overcome by a formulation of semisolid emulsion with sea buckthorn oil. Previous research on this formulation showed that it has higher wound healing potential than sea buckthorn oil, possessing an enhanced structure of liquid crystals, stability and suitability for topical use. The aim of this investigation was to completely characterizise a proposed emulsion by testing skin effects, such as moisturising potential, skin pH and potential to cause skin irritation. The emulsion was prepared by standard emulsifying techniques using a combination of surfactants that form an enhanced structure of liquid crystals. Approximately 40% of sea buckthorn oil was incorporated. The moisturising potential and skin pH were tested on the healthy skin of volunteers. Skin tolerance was tested on a rabbit skin model and evaluated by the Draize test. The tested emulsion containing sea buckthorn oil did not cause a significant change in skin pH, while it significantly increased skin hydration. Th ere was an absence of edema or erythema type of irritation after 2 h, 24 h, 48

Retrospective analysis of the Draize test for serious eye damage/eye irritation: importance of understanding the in vivo endpoints under UN GHS/EU CLP for the development and evaluation of in vitro test methods

For more than two decades, scientists have been trying to replace the regulatory in vivo Draize eye test by in vitro methods, but so far only partial replacement has been achieved. In order to better understand the reasons for this, historical in vivo rabbit data were analysed in detail and resampled with the purpose of (1) revealing which of the in vivo endpoints are most important in driving United Nations Globally Harmonized System/European Union Regulation on Classification, Labelling and Packaging (UN GHS/EU CLP) classification for serious eye damage/eye irritation and (2) evaluating the method’s within-test variability for proposing acceptable and justifiable target values of sensitivity and specificity for alternative methods and their combinations in testing strategies. Among the Cat 1 chemicals evaluated, 36–65 % (depending on the database) were classified based only on persistence of effects, with the remaining being classified mostly based on severe corneal effects. Iritis was found to rarely drive the classification (<4 % of both Cat 1 and Cat 2 chemicals). The two most important endpoints driving Cat 2 classification are conjunctiva redness (75–81 %) and corneal opacity (54–75 %). The resampling analyses demonstrated an overall probability of at least 11 % that chemicals classified as Cat 1 by the Draize eye test could be equally identified as Cat 2 and of about 12 % for Cat 2 chemicals to be equally identified as No Cat. On the other hand, the over-classification error for No Cat and Cat 2 was negligible (<1 %), which strongly suggests a high over-predictive power of the Draize eye test. Moreover, our analyses of the classification drivers suggest a critical revision of the UN GHS/EU CLP decision criteria for the classification of chemicals based on Draize eye test data, in particular Cat 1 based only on persistence of conjunctiva effects or corneal opacity scores of 4. In order to successfully replace the regulatory in vivo Draize eye test, it will be important to recognise these uncertainties and to have in vitro tools to address the most important in vivo endpoints identified in this paper.

A new alternative method for testing skin irritation using a human skin model: A pilot study

BackgroundStudies assessing skin irritation to chemicals have traditionally used laboratory animals; however, such methods are questionable regarding their relevance for humans. New in vitro methods have been validated, such as the reconstructed human epidermis (RHE) model (Episkin®, Epiderm®). The comparison (accuracy) with in vivo results such as the 4-h human patch test (HPT) is 76% at best (Epiderm®). There is a need to develop an in vitro method that better simulates the anatomo-pathological changes encountered in vivo. ObjectivesTo develop an in vitro method to determine skin irritation using human viable skin through histopathology, and compare the results of 4 tested substances to the main in vitro methods and in vivo animal method (Draize test). MethodologyHuman skin removed during surgery was dermatomed and mounted on an in vitro flow-through diffusion cell system. Ten chemicals with known non-irritant (heptylbutyrate, hexylsalicylate, butylmethacrylate, isoproturon, bentazon, DEHP and methylisothiazolinone (MI)) and irritant properties (folpet, 1-bromohexane and methylchloroisothiazolinone (MCI/MI)), a negative control (sodiumchloride) and a positive control (sodiumlaurylsulphate) were applied. The skin was exposed at least for 4h. Histopathology was performed to investigate irritation signs (spongiosis, necrosis, vacuolization). ResultsWe obtained 100% accuracy with the HPT model; 75% with the RHE models and 50% with the Draize test for 4 tested substances. The coefficients of variation (CV) between our three test batches were <0.1, showing good reproducibility. Furthermore, we reported objectively histopathological irritation signs (irritation scale): strong (folpet), significant (1-bromohexane), slight (MCI/MI at 750/250ppm) and none (isoproturon, bentazon, DEHP and MI). ConclusionsThis new in vitro test method presented effective results for the tested chemicals. It should be further validated using a greater number of substances; and tested in different laboratories in order to suitably evaluate reproducibility.

RGTA-based matrix therapy in severe experimental corneal lesions: Safety and efficacy studies

Corneal alteration potentially leading to ulceration remains a major health concern in ocular surface diseases. A treatment that would improve both the quality and speed of healing and control the inflammation would be of great interest. Regenerating agents (RGTAs) have been shown to stimulate wound healing and modulate undesired fibrosis in various in vivo systems. We investigated the effects of RGTA-OTR4120(®) in a rabbit corneal model in order to assess its potential use in ocular surface diseases. First, we assessed its safety for 7 and 28 days using the Draize test criteria in healthy rabbit eyes; then, we investigated the effect of a single dose (50μl, 5μg) in an alkali-burned cornea model. Daily follow-up of clinical signs of healing was scored, and histology was performed at D7. RGTA was well tolerated; no signs of ocular irritation were observed. In the corneal alkali-burn model, non-RGTA-treated eyes showed inflammatory clinical signs, and histology confirmed a loss of superficial corneal layers with epithelial disorganization, neovascularization and infiltration of inflammatory cells. When compared to NaCl control, RGTA treatment appeared effective in reducing clinical signs of inflammation, enhancing re-epithelialization, and improving histological patterns: edema, fibrosis, neovascularization and inflammation. Three to four layers of epithelial cells were already organized, stroma was virtually unvascularized and keratocytes well implanted in parallel collagen fibers with an overall reorganization similar to normal cornea. RGTA appears to be a promising agent for controlling ocular surface inflammation and promoting corneal healing and was well tolerated. This study offers preclinical information and supports the findings of other (compassionate or pilot) studies conducted in patients with various ocular surface diseases.

Draize test for eye irritation: Importance of the endpoints evaluated with regard to UN GHS/EU CLP classification

Draize test for eye irritation: Importance of the endpoints evaluated with regard to UN GHS/EU CLP classification

Development of acetazolamide-loaded, pH-triggered polymeric nanoparticulate in situ gel for sustained ocular delivery: in vitro. ex vivo evaluation and pharmacodynamic study

The objective of research was to develop a novel pH-triggered polymeric nanoparticulate in situ gel (NP-ISG) for ophthalmic delivery of acetazolamide (ACZ) to enhance the conjunctival permeation and precorneal residence time of the formulation by overcoming the limitations of protective ocular barriers. Nanoparticles (NP1--NP12) were developed by nanoprecipitation method and evaluated for pharmacotechnical characteristics including transmission electron microscopy. The optimized formulation, NP10 was dispersed in carbopol 934 P to form nanoparticulate in situ gels (NP-ISG1--NP-ISG5). NP-ISG5 was selected as optimized formulation on the basis of gelation ability and residence time. Ex vivo transcorneal permeation study exhibited significantly higher ACZ permeation from NP-ISG5 (74.50 ± 2.20 mg/cm2) and NP10 (93.5 ± 2.25 mg/cm2) than eye drops (20.08 ± 3.12 mg/cm2) and ACZ suspension (16.03 ± 2.14). Modified Draize test with zero score indicated nonirritant property of NP-ISG5. Corneal toxicity study revealed no visual signs of tissue damage. Further, NP-ISG5 when tested for hypotensive effect on intraocular pressure (IOP) in rabbits revealed that NP-ISG5 caused significant decrease in IOP (p < 0.05) in comparison to eye drops. Conclusively, NP-ISG5 may offer intensive management of glaucoma via higher permeation, prolonged precorneal residence time and sustained drug release along with higher in vitro efficacy, safety and patient compliance.

Ophthalmic Delivery of Brinzolamide by Liquid Crystalline Nanoparticles: In Vitro and In Vivo Evaluation

Brinzolamide (BLZ) is a drug used to treat glaucoma; however, its use is restricted due to some unwanted adverse events. The goal of this study was to develop BLZ-loaded liquid crystalline nanoparticles (BLZ LCNPs) and to figure out the possibility of LCNPs as a new therapeutic system for glaucoma. BLZ LCNPs were produced by a modified emulsification method and their physicochemical aspects were estimated. In vitro release study revealed BLZ LCNPs displayed to some extent prolonged drug release behavior in contrast to that of BLZ commercial product (Azopt®). The ex vivo apparent permeability coefficient of BLZ LCNP systems demonstrated a 3.47-fold increase compared with that of Azopt®. The pharmacodynamics was checked over by calculating the percentage fall in intraocular pressure and the pharmacodynamic test showed that BLZ LCNPs had better therapeutic potential than Azopt®. Furthermore, the in vivo ophthalmic irritation was evaluated by Draize test. In conclusion, BLZ LCNPs would be a promising delivery system used for the treatment of glaucoma, with advantages such as lower doses but maintaining the effectiveness, better ocular bioavailability, and patient compliance compared with Azopt®.

FORMULATION AND EVALUATION OF MOXIFLOXACIN HYDROCHLORIDE OCULAR NANOPARTICLES

The objective of the present study was to prepare controlled release formulation of Moxifloxacin hydrochloride ocular nanoparticles. The nanoparticles were prepared by solvent displacement method using Eudragit RL 100 as a polymer. Different formulations were prepared by varying the ratios of drug and polymer and varying the ratios of organic and aqueous phase. The formulations were evaluated in terms of particle size, FTIR, drug entrapment efficiency and in vitro drug release profile was examined. The anti bacterial activity against gram positive and gram negative bacteria were determined. In vivo studies were carried out by Draize test. The mean particle size for drug loaded formulations was found to be below 200 nm. The zeta potential remained in the range of positive values for all batches +10 mV to +40mV. The formulation possesses good antibiotic activity against Escherichia coli, Bacillus subtilus and Staphylococcus aureus microorganism and no eye irritation on in-vivo testing.

Predicting Chemical Ocular Toxicity Using a Combinatorial QSAR Approach

Regulatory agencies require testing of chemicals and products to protect workers and consumers from potential eye injury hazards. Animal screening, such as the rabbit Draize test, for potential environmental toxicants is time-consuming and costly. Therefore, virtual screening using computational models to tag potential ocular toxicants is attractive to toxicologists and policy makers. We have developed quantitative structure-activity relationship (QSAR) models for a set of small molecules with animal ocular toxicity data compiled by the National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods. The data set was initially curated by removing duplicates, mixtures, and inorganics. The remaining 75 compounds were used to develop QSAR models. We applied both k nearest neighbor and random forest statistical approaches in combination with Dragon and Molecular Operating Environment descriptors. Developed models were validated on an external set of 34 compounds collected from additional sources. The external correct classification rates (CCR) of all individual models were between 72 and 87%. Furthermore, the consensus model, based on the prediction average of individual models, showed additional improvement (CCR = 0.93). The validated models could be used to screen external chemical libraries and prioritize chemicals for in vivo screening as potential ocular toxicants.

Nano and microparticulate chitosan-based systems for antiviral topical delivery

Acyclovir (ACV) is one of the drugs of choice for the treatment of epidermal, ocular or systemic herpetic infections. Nevertheless, its trans-mucosal limited absorption and the scarce contact time of the formulation with the mucosal surface – especially in the ocular mucosa – constitute a big limitation of the antiviral efficiency. The most effective way to solve these problems is to increase the quantity and the residence time of the drug over the ocular surface. In order to cope with all these requirements, micro-particles (MPs) and nano-particles (NPs) containing ACV have been developed using cross-linked chitosan with tripolyphosphate (TPP) due to the biocompatibility, bio-adhesion ability and the potential power as penetration enhancer of this polymer. Particles were characterized by Fourier-transformed infrared (FTIR) spectroscopy, X-ray diffraction, SEM, Zeta potential and particle size. Encapsulation efficiency and release profiles in flow through diffusion cells were also determined. Besides the Slug Mucosal Irritation (SMI) assay has been applied as an alternative to the Draize test to predict the mucosal irritation of the selected formulation.FTIR and X-ray results suggested an electrostatic interaction ACV-Chitosan that made ACV be molecularly dispersed within the polymer matrix. Encapsulation efficiency was 75% for MP and 16% for NP. Release profiles in flow through diffusion cells were also determined. From the diffusion profiles, it was found that the amounts of ACV effectively diffused in 24h were 30, 430 and 80μg for the ACV solution, MP and NP respectively. SMI results showed that chitosan-based particles induced moderate irritation and mild tissue damage, what supposes that ACV-MP constitute a promising alternative for further development of an antiviral formulation.

Ethogel topical formulation for increasing the local bioavailability of 5-fluorouracil

5-Fluorouracil (5-FU) is an anticancer drug and is considered a gold standard for the treatment of skin cancer. At present, topical chemotherapy with 5-FU is associated with the limitations of poor skin permeation, retention at target site, and skin irritation potential. In the present study, an attempt has been made to develop an ethosome-based topical gel formulation (ethogel) for skin targeting of 5-FU. The ethosomal formulation was prepared using the classical dispersion method, and loading of 5% w/w of the drug was optimized to the commercial strength of marketed 5-FU cream. Carbopol 934P was used as a gel former in 0.5, 0.75, 1.0, and 1.5% w/w concentration for preparation of ethosome-based ethogel formulation. The ethogel formulation was characterized for viscosity, spreadability, extrudability, and pH. Viscosity of the developed ethogel and that of the marketed formulation was found to be 3070±14.7 and 2870±14.4 cP, respectively. An in-vitro skin permeation and deposition study was carried out across rat skin using the marketed cream and 5-FU drug solution as controls. The amount of drug deposition was found to increase 5.9- and 9.4-fold on treatment with ethogel in comparison with the marketed cream and drug solution, respectively. The result of antitumor activity evaluated using a Cytoselect 96-well cell transformation assay revealed a large reduction in tumor density with treatment with the 5-FU ethogel formulation in comparison with the marketed formulation. A significant reduction in the skin irritation potential of 5-FU ethogel formulation was also found in comparison with that of the marketed formulation as measured by the Draize test. The results of the present study demonstrated ethogel as a better alternative for increasing the local bioavailability of 5-FU in comparison to the marketed formulation.