Experimental studies on soft contact lenses for controlled ocular delivery of pirfinedone: in vitro and in vivo

Context: Pirfinedone (PFD) is a novel agent which has the potential to prevent scarring in the eyes. The 0.5% PFD eye drops exhibits poor bioavailability. Whereas, the feasibility of using contact lens as ocular drug delivery device initiated novel possibilities.

Objective: To evaluate the delivery of PFD by soft contact lens (SCL) in vivo, we screened the most suitable lens material for PFD among various commercially available SCL materials in vitro.

Material and methods: Firstly, 11 different SCLs (?1.00 diopter) were respectively soaked in 2?ml of 0.05% PFD-loading solution for 24?h to fully absorb drug, and then placed in fresh phosphate buffered saline (PBS) to release the drug. PFD concentration in PBS was determined by ultraviolet absorbance at 310?nm. Secondly, by immersing in 2?ml of 0.5% PFD eye drops for 24?h, the polymacon lens (0.00 diopter) was then placed on the cornea of New Zealand rabbits. PFD concentrations were detected by high performance liquid chromatography (HPLC) in tears, aqueous humor, conjunctiva, cornea, and sclera at different time points.

Results: PFD showed some affinity for pHEMA-based lenses and the polymacon lens more slowly released more amount of PFD than any other lens in vitro (p < 0.001). Compared with eye drops, drug-loaded SCLs greatly enhanced the retention time and concentrations of PFD in cornea and aqueous humor and consequently improved the bioavailability of PFD.

Conclusion: Polymacon-based SCL is probably a promising vehicle to be an effective ophthalmic delivery system for PFD.     

In vitro and in vivo evaluation of ketotifen fumarate-loaded silicone hydrogel contact lenses for ocular drug delivery

The purpose of this work was to evaluate the usefulness of silicone hydrogel contact lenses loaded with ketotifen fumarate for ocular drug delivery. First, silicone contact lenses were prepared by photopolymerization of bitelechelic methacrylated polydimethylsiloxanes macromonomer, 3-methacryloxypropyltris(trimethylsiloxy)silane, and N,N-dimethylacrylamide using ethylene glycol dimethacrylate as a cross-linker and Darocur 1173 as an initiator followed by surface plasma treatment. Then, the silicone hydrogel matrices of the contact lenses were characterized by equilibrium swelling ratio (ESR), tensile tests, ion permeability, and surface contact angle. Finally, the contact lenses were loaded with ketotifen fumarate by pre-soaking in drug solution to evaluate drug loading capacity, in vitro and in vivo release behavior of the silicone contact lenses. The results showed that ESR and ion permeability increase, and the surface contact angle and tensile strength decreased with the increase of DMA component in the silicone hydrogel. The drug loading and in vitro releases were dependent on the hydrogel composition of hydrophilic/hydrophobic phase of the contact lenses. In rabbit eyes, the pre-soaked contact lenses sustained ketotifen fumarate release for more than 24?h, which leads to a more stable drug concentration and a longer mean retention time in tear fluid than that of eye drops of 0.05%.     

Preservative-free versus preserved brimonidine %0.15 preparations in the treatment of glaucoma and ocular hypertension: short term evaluation of efficacy,safety, and potential advantages

Abstract

Purpose: To compare the efficacy, safety, and potential advantages of the preservative-free versus preserved brimonidine %0.15 preparations in patients with primer open-angle glaucoma (POAG) or ocular hypertension (OHT).

Methods: Forty-two eyes of the 21 treatment-naive patients with POAG or OHT were enrolled in this study. Eyes were randomly assigned to receive brimonidine-purite 0.15% or preservative-free brimonidine 0.15% two times daily. Efficacy of the two eye drops was assessed by measuring the intraocular pressure (IOP) at 9–10 am at baseline and week 4. Safety and potential advantages of the drops were evaluated at weeks 4 in terms of ocular symptoms and tear parameters. Ocular symptom values of the patients were evaluated with a scale of 0–4 (0?=?no discomfort and 4?=?severe discomfort).

Results: Both of the brimonidine tartrate formulations resulted in statistically similar IOP reduction (preserved formulation; ?5.2?mmHg [22.9% reduction] preservative-free formulation; ?5.7?mmHg [24.1% reduction], p?=?0.37). It was found that brimonidine tartrate formulations with and without topical preservatives did not produce a statistically significant difference in pain, stinging, and blurred vision at the upon instillation (p?>?0.05). However, the burning sensation was significantly higher in the preservative-free formulation at the first instillation compared to the preserved formulation (p?=?0.01). Also, there was no statistically significant difference between the two formulations in terms of symptoms (itching, burning, tearing, stinging, and photophobia) and tear parameters during the day (p?>?0.05).

Conclusions: Although topical preservative-free brimonidine tartrate treated eyes had a more burning sensation at the first drop, the two formulations were similar in terms of ocular tolerability in the short term period. Also, both formulations were found to reduce IOP at a similar rate.     

Controlled release of betamethasone from vitamin E-loaded silicone-based soft contact lenses

Context: Betamethasone (BMZ) is an effective drug which is commonly used as an eye drop for the management of ophthalmic inflammations. Due to low ocular bioavailability, it is necessary to prepare and optimize an ocular drug delivery system for BMZ.

Objective: In this study we tried to use vitamin E diffusion barrier for sustaining BMZ release.

Materials and methods: Three commercial contact lenses were soaked in vitamin E solutions and swelling percentage, diameter, transmittance, binding capacity and release amount and time were evaluated in comparison with non-vitamin E-loaded pure lenses.

Results: The results showed that vitamin E significantly decreased water content of contact lenses whereas, increased the lens diameter in both dry and wet states. It effectively blocked UV radiation which is harmful for the eye surface while had no significant effect on visible transmittance. BMZ loading capacity enhanced and release rate remarkably decreased after using vitamin E as a hydrophobic diffusion barrier.

Discussion and conclusions: This study revealed that vitamin E can be applied as a hydrophobic diffusion barrier for controlling and sustaining BMZ release from silicone-based soft contact lenses into the lachrymal fluid. It can also protect eye tissues as an antioxidant by blocking the UV radiation.     

Fabrication and evaluation of lipid nanoparticulates for ocular delivery of a COX-2 inhibitor

Context: The unique physiological limitations of the eye have been assigned as reason of low bioavailability by conventional drug delivery systems. There is need of such drug carriers, which ensure improved bioavailability as well as patient compliance upon instillation into the eye.

Objective: The present investigation deals with development of solid lipid nanoparticles (SLNs) containing celecoxib (CXB) for treatment of ophthalmic inflammations.

Materials and methods: The SLNs were formulated by melt-emulsion sonication and low temperature-solidification process and evaluated for particle size, surface morphology, physicochemical properties, percentage drug incorporation efficiency, in vitro drug release, in vitro trans-corneal permeation, in vivo efficacy in ocular inflammation, stability study and gamma scintigraphy study to assess the residence of solid lipid nanoparticles over ocular surfaces.

Results: The SLNs were spherical and the optimized formulation had particle size of 198.77?±?7.5?nm, which is quite suitable for ocular applications. The maximum entrapment efficiency of 92.46?±?0.07% was achieved for formulation SLN 20. The permeation across the cornea was also significantly better than aqueous suspension (8.21?±?0.67 versus 4.61?±?0.71) at p?<?0.05.

Discussion and conclusion: The SLN formulations demonstrated improved performance of entrapped CXB while mitigating the key parameters of ocular inflammation in rabbits. The particulate formulations have exhibited prolonged retention over ocular surfaces as evident from results of gamma scintigraphy using ^99mTc labeled SLNs.     

Investigation of true nanoemulsions for transdermal potential of indomethacin: characterization,rheological characteristics,and ex vivo skin permeation studies

The aim of the present study was to investigate the potential of true nanoemulsions for transdermal delivery of indomethacin. Thermodynamically stable true nanoemulsions were characterized for morphology using transmission electron microscopy (TEM), droplet size, rheological characteristics, and refractive index. The rheological behavior for all true nanoemulsions was found to be Newtonian as viscosity was unchanged by increasing the rate of shear. The ex vivo skin permeation studies were performed using Franz diffusion cell with rat skin as permeation membrane. The ex vivo skin permeation profile of optimized formulation was compared with marketed Indobene gel and nanoemulsion gel. Significant increase in permeability parameters was observed in nanoemulsion formulations (P?<?0.05). The steady-state flux (J_ss) and permeability coefficient (K_p) for optimized nanoemulsion formulation were found to be 73.96?±?2.89?μg/cm²/h and 1.479?×?10^?2?±?0.289?×?10^??2?cm/h, respectively, which were significant compared with Indobene gel and nanoemulsion gel (P?<?0.05). Enhancement ratio (E_r) was found to be 7.88 in optimized formulation F6 compared with other formulations. These results suggested that nanoemulsions can be used as potential vehicles for improved transdermal delivery of indomethacin.     

Contact lenses as a platform for ocular drug delivery

Introduction: Most ophthalmic drugs are delivered through eye drops even though only about 1 – 5% of the drug reaches the target tissue and the patient compliance is not good. Drug-eluting contact lenses could significantly increase bioavailability, reduce side effects and improve patient compliance.

Areas covered: Recent research on drug-eluting contact lenses has focused on increasing the release duration through molecular imprinting, dispersion of barriers or nanoparticles, increasing drug binding to the polymer, sandwiching a PLGA (poly[lactic-co-glycolic acid]) layer in a lens and developing novel materials. This review covers all these studies with a specific focus on the transport mechanisms and advantages and disadvantages of each approach.

Expert opinion: The main reason for prior failures was the short duration of release from the lenses. The new technologies can provide extended drug release for hours to days. The in vivo animal and clinical studies have proven the safety and efficacy of drug-eluting contact lenses, while showing considerable improvements compared to eye drops. The future appears to be promising but several challenges remain such as processing and storage issues, regulatory hurdles, high costs of clinical studies, potential lack of acceptance by the elderly, etc.     

A review on therapeutic contact lenses for ocular drug delivery

Contact lenses for ophthalmic drug delivery have become very popular, due to their unique advantages like extended wear and more than 50% bioavailability. To achieve controlled and sustained drug delivery from contact lenses, researchers are working on various systems like polymeric nanoparticles, microemulsion, micelle, liposomes, use of vitamin E, etc. Numerous scientists are working on different areas of therapeutic contact lenses to treat ocular diseases by implementing techniques like soaking method, molecular imprinting, entrapment of drug-laden colloidal nanoparticles, drug plate/film, ion ligand polymeric systems, supercritical fluid technology, etc. Though sustained drug delivery was achieved using contact lens, the critical properties such as water content, tensile strength (mechanical properties), ion permeability, transparency and oxygen permeability were altered, which limit the commercialization of therapeutic contact lenses. Also issues like drug stability during processing/fabrication (drug integrity test), zero order release kinetics (prevent burst release), drug release during monomer extraction step after fabrication (to remove un-reacted monomers), protein adherence, drug release during storage in packaging solution, shelf life study, cost-benefit analysis, etc. are still to be addressed. This review provides an expert opinion on different methodology to develop therapeutic contact lenses with special remark of their advantages and limitations.     

Topical delivery of aceclofenac as nanoemulsion comprising excipients having optimum emulsification capabilities: preparation,characterization and in vivo evaluation

Objective: The aim of the present study was to investigate the potential of a nanoemulsion for topical delivery of aceclofenac using different excipients having optimum emulsifying ability rather than their solubilizing capacity.

Methods: The oil-in-water nanoemulsions were prepared by screening the excipients from the nanoemulsion region of pseudoternary phase diagram. The prepared nanoemulsions were subjected to different thermodynamic stability tests. The nanoemulsion formulations that passed thermodynamic stability tests were characterized for viscosity, droplet size, transmission electron microscopy, refractive index and in vitro skin permeation. The in vitro skin permeation profile of optimized nanoemulsion formulation (NE31, containing 23.85% Polyoxy-35-castor oil, 7.95% PEG 400 and 13.6% Triacetin) was compared with that of nanoemulsion gel (NG31) and marketed gel formulation (HIFENAC GEL (HIG)). In vivo anti-inflammatory efficacy studies were also carried out for NE31, NG31 and HIG.

Results: The significant (p < 0.001) increase in in vitro permeability and in vivo anti-inflammatory efficacy of the NG31 formulation was observed as compared with HIG formulation.

Conclusion: It can be concluded that the selection of surfactant and cosurfactant on the basis of their emulsification capabilities other than the solubilizing capacity of drug is an important criterion for the formulation of nanoemulsion.     

In vivo tissue distribution and efficacy studies for cyclosporin A loaded nano-decorated subconjunctival implants

Biodegradable implants are promising drug delivery systems for sustained release ocular drug delivery with the benefits such as minimum systemic side effects, constant drug concentration at the target site and getting cleared without surgical removal. Dry eye syndrome (DES) is a common disease characterized with the changes in ocular epithelia surface and results in inflammatory reaction that might lead to blindness. Cyclosporin A (CsA) is a cyclic peptide that is frequently employed for the treatment of DES and it needs to be applied several times a day in tear drops form. The aim of this study was to evaluate in vivo behavior and efficacy of the developed nano-decorated subconjunctival implant systems for sustained release CsA delivery. Biodegradable Poly-?-caprolactone (PCL) implant or micro-fiber implants containing CsA loaded poly-lactide-co-glycolide (85:15) (PLGA) or PCL nanoparticles were prepared in order to achieve sustained release. Two of the formulations PCL–PLGA–NP-F and PCL-PCL-NP-I were selected for in vivo evaluation based on their in vitro characteristics determined in our previous study. In this study, formulations were implanted to Swiss Albino mice with induced dry eye syndrome to investigate the ocular distribution of CsA following subconjunctival implantation and to evaluate the efficacy. Tissue distribution study indicated that CsA was present in ocular tissues such as cornea, sclera and lens even 90 days after the application and blood CsA levels were found lower than ocular tissues. Efficacy studies also showed that application of CsA-loaded fiber implant formulation resulted in faster recovery based on their staining scores.     

In vitro and in vivo evaluation of ketotifen fumarate-loaded silicone hydrogel contact lenses for ocular drug delivery

The purpose of this work was to evaluate the usefulness of silicone hydrogel contact lenses loaded with ketotifen fumarate for ocular drug delivery. First, silicone contact lenses were prepared by photopolymerization of bitelechelic methacrylated polydimethylsiloxanes macromonomer, 3-methacryloxypropyltris(trimethylsiloxy)silane, and N,N-dimethylacrylamide using ethylene glycol dimethacrylate as a cross-linker and Darocur 1173 as an initiator followed by surface plasma treatment. Then, the silicone hydrogel matrices of the contact lenses were characterized by equilibrium swelling ratio (ESR), tensile tests, ion permeability, and surface contact angle. Finally, the contact lenses were loaded with ketotifen fumarate by pre-soaking in drug solution to evaluate drug loading capacity, in vitro and in vivo release behavior of the silicone contact lenses. The results showed that ESR and ion permeability increase, and the surface contact angle and tensile strength decreased with the increase of DMA component in the silicone hydrogel. The drug loading and in vitro releases were dependent on the hydrogel composition of hydrophilic/hydrophobic phase of the contact lenses. In rabbit eyes, the pre-soaked contact lenses sustained ketotifen fumarate release for more than 24?h, which leads to a more stable drug concentration and a longer mean retention time in tear fluid than that of eye drops of 0.05%.     

Hydrogels in ophthalmic applications

More and more people worldwide are affected by severe eye diseases eventually leading to visual impairment or blindness. In most cases, the treatment involves the application of ophthalmic dosage forms such as eye drops, suspensions or ointments. Unfortunately, some of the therapeutic approaches have major shortcomings, especially in the treatment of the posterior segment of the eye, where many vision-threatening diseases originate. Therefore, research focuses on the development of new materials (e.g., for vitreous substitution) and more advanced drug delivery systems. Hydrogels are an extremely versatile class of materials with many potential applications in ophthalmology. They found widespread application as soft contact lenses, foldable intraocular lenses, in situ gelling formulations for ophthalmic drug delivery and ocular adhesives for wound repair; their use as vitreous substitutes and intravitreal drug delivery systems is currently under investigation. In this article, we review the different applications of hydrogels in ophthalmology with special emphasis placed on the used polymers and their suitability as ocular drug delivery systems.     

The effect of gatifloxacin 0.3% or moxifloxacin 0.5% on corneal healing,ocular tolerability and toxicity following pterygium surgery

Purpose: To compare the rate of corneal epithelial healing and ocular tolerability following pterygium surgery between gatifloxacin and moxifloxacin.

Methods: In this double masked, prospective, controlled study 40 patients were randomized to receive prophylactic topical gatifloxacin 0.3% or moxifloxacin 0.5% following pterygium surgery. Patients were examined on days 1, 3, 7 and 21 post-operatively or until complete corneal epithelial healing. The primary outcome measure was the area of corneal epithelial defect during the post-operative period. Patients graded post-operative ocular pain, foreign body sensation, tearing, general burning sensation and burning sensation post-antibiotic drops instillation on a scale of 1–5. Conjunctival hyperemia and superficial punctate keratopathy (SPK) were measured on a scale of 0–3.

Results: No significant differences between groups were found in terms of corneal epithelial defect percentage over time (p?=?0.989) and there was no significant difference between groups on each of the post-operative days. No significant differences were noted in terms of post-operative ocular pain, foreign body sensation, tearing, general burning sensation, burning sensation post-antibiotic drops instillation, conjunctival hyperemia and SPK.

Conclusions: Gatifloxacin and moxifloxacin showed equivalent results in terms of corneal epithelial healing and ocular tolerability following pterygium surgery. This study suggests that there was no apparent added epithelial toxicity due to the presence of benzalkonium chloride in the gatifloxacin preparation when compared to moxifloxacin.     

Chemoprevention of skin cancer using low HLB surfactant nanoemulsion of 5-fluorouracil: a preliminary study

Abstract

Oral delivery of 5-fluorouracil (5-FU) is difficult due to its serious adverse effects and extremely low bioavailability. Therefore, the aim of present investigation was to develop and evaluate low HLB surfactant nanoemulsion of 5-FU for topical chemoprevention of skin cancer. Low HLB surfactant nanoemulsions were prepared by oil phase titration method. Thermodynamically stable nanoemulsions were characterized in terms of droplet size distribution, zeta potential, viscosity and refractive index. Selected formulations and control were subjected to in vitro skin permeation studies through rat skin using Franz diffusion cells. Optimized formulation F9 was subjected to stability and in vitro cytotoxic studies on melanoma cell lines. Enhancement ratio was found to be 22.33 in formulation F9 compared with control and other formulations. The values of steady state flux and permeability coefficient for formulation F9 were found to be 206.40?±?14.56?µg?cm^?2?h^?1 and 2.064?×?10^?2?±?0.050?×?10^?2?cm?h^?1, respectively. Optimized formulation F9 was found to be physical stable. In vitro cytotoxicity studies on SK-MEL-5 cancer cells indicated that 5-FU in optimized nanoemulsion is much more efficacious than free 5-FU. From these results, it can be concluded that the developed nanoemulsion might be a promising vehicle for chemoprevention of skin cancer.     

Efficacy and comfort of olopatadine 0.2% versus epinastine 0.05% ophthalmic solution for treating itching and redness induced by conjunctival allergen challenge

ABSTRACT

Background: Olopatadine 0.2% (Pataday, Alcon Laboratories Inc., Fort Worth, Texas, USA) and epinastine 0.05% (Elestat, Inspire Pharmaceuticals, Inc., Durham, NC, USA) are topical ocular anti-allergic agents. Both are H₁ antihistamine/mast cell stabilizers indicated for the treatment of ocular itching associated with allergic conjunctivitis.

Objective: To compare the efficacy and comfort of olopatadine 0.2% with epinastine 0.05%, in the prevention of ocular itching associated with allergic conjunctivitis following conjunctival allergen challenge (CAC).

Research design and methods: This was a 7 week, four visit, double-masked, randomized, placebo-controlled CAC study. Visit 1 screened subjects for positive ocular allergic responses and Visit 2 confirmed those responses. At Visit 3, 92 subjects were randomized into one of four treatment groups to receive one drop of study medication in each eye: (1) olopatadine 0.2%/placebo, (2) epinastine 0.05%/placebo, (3) olopatadine 0.2%/epinastine 0.05%, (4) placebo/placebo. Subjects were challenged 12?h after drop instillation to evaluate duration of action. At Visit 4, subjects were challenged 5?min after drop instillation to evaluate onset of action. Drop comfort was assessed at Visit 4.

Main outcome measures; results: This article focuses on the results of the onset-of-action challenge (Visit 4). At Visit 4, ocular itching was assessed at 3, 5, and 7?min and redness was assessed at 7, 15, and 20?min post-challenge. Drop comfort was assessed upon instillation, at 30?s, and at 1, 2, and 5?min post-instillation. Olopatadine 0.2%-treated eyes exhibited significantly lower mean ocular itching scores versus epinastine 0.05%-treated eyes at 5 (?p = 0.024) and 7?min (?p = 0.003) post-challenge. Olopatadine 0.2%-treated eyes exhibited significantly lower mean redness scores versus epinastine 0.05%-treated eyes at all time points post-challenge (ciliary: p ≤ 0.013, conjunctival: p ≤ 0.015, episcleral: p ≤ 0.006). Olopatadine 0.2% was rated as significantly more comfortable than epinastine 0.05% at 1?min post-drop instillation (?p = 0.003). All adverse events were non-serious and unrelated to study medication. Although the CAC model reproduces allergic responses that are not environmentally-induced, patients experience varying severities of responses as are seen in real-world situations.

Conclusion: Olopatadine 0.2% was superior to epinastine 0.05% in preventing ocular itching and redness at onset when induced by the CAC model.     

Molecularly imprinted therapeutic contact lenses

Importance of the field: There exists a considerable unmet need for more efficacious delivery of ocular therapeutics. Contact lenses have been developed with high loading and controllable sustained release to overcome limited patient compliance and significant ocular transport limitations. This can best be achieved by extending and controlling the residence time of drugs on the eye surface and thereby limiting drug loss by lacrimation, drainage and non-productive absorption.

Areas covered in the review: Within hydrogels, molecular imprinting can be used to create memory for template molecules embedded within a flexible macromolecular network. Control in therapeutic loading and delay of release have been demonstrated with careful attention to the functional monomer/template ratio, the diversity of functional monomers, and the polymer backbone and network structure. Experimental work has also confirmed that macromolecular memory and not structural differences or phenomena are responsible for delayed drug release kinetics compared with non-imprinted systems. A therapeutically relevant amount of drug can be loaded for release to occur over multiple days, which allows the technique to be applied to daily-wear and extended-wear contact lenses.

What the reader will gain: The focus of this article is to review the emerging field of molecularly imprinted contact lenses and highlight significant accomplishments, trends, as well as future strategies and directions.

Take home message: In the past 8 years, molecular imprinting has been used to produce therapeutic contact lenses with enhanced loading and delayed release. Progress in the field has mostly included low-molecular-weight therapeutics such as anti-glaucoma, antihistamine, antibiotic and anti-inflammatory therapeutics used to treat anterior eye disorders. Recently, high molecular weight comfort molecules have also been successfully demonstrated. Current methods can produce lenses of suitable thickness, water content, and mechanical and optical properties compared with commercial lenses on the market today.     

Evaluation of the anticancer activity of sprout extract-loaded nanoemulsion of N. sativa against hepatocellular carcinoma

Abstract

Nigella sativa L. belonging to Ranunculaceae family is an important medicinal spice which has been utilised to treat various chronic diseases. Lipid nanoemulsions containing oil from medicinal plants have shown to enhance drug dissolvability, diminish symptoms of different powerful medications and enhance the bioavailability of medications, in contrast with conventional formulations. In the present study, aqueous titration method was used to prepare nanoemulsion. The optimised formulation (NE₁₁) with the mean particle size of 37.47?nm showed a minimum viscosity of 0.547 cps and maximum drug release (98.2%) in 24?h. The stability study showed considerably stable formulations at refrigerator temperature as compared to room temperature. The cancer cell line studies confirmed that 5d sprout extract of N. sativa nanoemulsion reduced the cell viability (p?<?.05) and increased colony formation, ROS intensity and chromatin condensation. All data such as colony formation, ROS intensity and chromatin condensation are represented as mean?±?SD (p?<?.001) treated cells for 48?hours. Our results concluded that the development of nanoemulsion could be an efficient carrier for drug delivery.     

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

Abstract

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.     

Topical delivery of acyclovir and ketoconazole

Abstract

Context: Viral and fungal cutaneous manifestations are regularly encountered in immunocompromised human immunodeficiency virus/acquired immunodeficiency syndrome individuals and can be treated by drugs such as acyclovir and ketoconazole, respectively.

Objective: The aim of this study was to determine whether the novel Pheroid? delivery system improved the transdermal delivery and/or dermal delivery of acyclovir and ketoconazole when incorporated into semi-solid formulations.

Materials and methods: Semi-solid products (creams and emulgels) containing these drug compounds were formulated, either with or without (control) the Pheroid? delivery system. The stability of the formulated semi-solid products was examined over a period of six months and included the assay of the actives, pH, viscosity, mass loss and particle size observation. Vertical Franz cell diffusion studies and tape stripping methods were used to determine the in vitro, stratum corneum (SC)-epidermis and epidermis-dermis delivery of these formulations.

Results and discussion: Stability tests showed that none of the formulations were completely stable. Acyclovir showed a biphasic character during the in vitro skin diffusion studies for all the tested formulations. The Pheroid? cream enhanced the transdermal, SC-epidermis and epidermis–dermis delivery of acyclovir the most. The average amount of ketoconazole diffused over 12?h showed improved delivery of ketoconazole, with the Pheroid? emulgel exhibiting the best transdermal and epidermis–dermis delivery.

Conclusion: The Pheroid? formulae increased transdermal penetration as well as delivery to the dermal and epidermal skin layers. The Pheroid? emulgel and the Pheroid? cream increased the topical delivery of ketoconazole and acyclovir, respectively.