Effect of formulation components on the in vitro permeation of microemulsion drug delivery system of fluconazole

Nanotechnology-based Drug Delivery of Topical Antifungal Agents

Among the various prominent fungal infections, superficial ones are widespread. A large number of antifungal agents and their formulations for topical use are commercially available. They have some pharmacokinetic limitations which cannot be retracted by conventional delivery systems. While nanoformulations composed of lipidic and polymeric nanoparticles have the potential to overcome the limitations of conventional systems. The broad spectrum category of antifungals i.e. azoles (ketoconazole, voriconazole, econazole, miconazole, etc.) nanoparticles have been designed, prepared and their pharmacokinetic and pharmacodynamic profile was established. This review briefly elaborates on the types of nano-based topical drug delivery systems and portrays their advantages for researchers in the related field to benefit the available antifungal therapeutics.

The Enhanced Skin Permeation of Flavonoids Via the Application of a Coamorphous in a Microemulsion Formulation

Improving the permeability and solubility of poorly water-soluble compounds is a major difficulty in skin permeation. In this study, we investigated whether using a pharmaceutical technique such as applying coamorphous to a microemulsion enhances the skin permeation of polyphenolic compounds. The melt-quenching technique created the coamorphous system between naringenin (NRG) and hesperetin (HPT), two polyphenolic compounds with poor water solubility. By creating a supersaturated state, the aqueous solution of coamorphous NRG/HPT demonstrated improved NRG and HPT skin permeation. However, as both compounds precipitated, the supersaturation ratio decreased. In contrast to crystal compounds, incorporating coamorphous material into microemulsions enabled the preparation of microemulsions in a wider formulation range. Additionally, compared to microemulsions with crystal compounds and an aqueous suspension of coamorphous, microemulsions with coamorphous NRG/HPT increased skin permeation of both compounds by more than four times. These results suggested that interactions between NRG and HPT are maintained in the microemulsion and enhance both compounds' skin permeation. An approach for improving the skin permeation of poorly water-soluble chemicals would be to apply a coamorphous system to a microemulsion.

Comprehensive Review on Applications of Surfactants in Vaccine Formulation, Therapeutic and Cosmetic Pharmacy and Prevention of Pulmonary Failure due to COVID-19

Our world is under serious threat of environmental degradation, climate change and in association with this the out breaks of diseases as pandemics. The devastating impact of the very recent COVID-19, The sharp increase in cases of Cancer, Pulmonary failure, Heart health has triggered questions for the sustainable development of pharmaceutical and medical sciences. In the search of inclusive and effective strategies to meet today’s demand, improvised methodologies and alternative green chemical, bio-based precursors are being introduced by scientists around the globe. In this extensive review we have presented the potentiality and Realtime applications of both synthetic and bio-based surfactants in bio-medical and pharmaceutical fields. For their excellent unique amphoteric nature and ability to solubilise in both organic and inorganic drugs, surfactants are one of the most potential candidates for bio-medicinal fields such as dermatology, drug delivery, anticancer treatment, surfactant therapy, vaccine formulation, personal hygiene care and many more. The self-assembly property of surfactants is a very powerful function for drug delivery systems that increases the bio-availability of the poorly aqueous soluble pharmaceutical products by influencing their solubility. Over the decades many researchers have reported the antimicrobial, anti-adhesive, antibiofilm, anti-inflammatory, antioxidant activities of surfactants regarding its utility in medicinal purposes. In some reports surfactants are found to have spermicidal and laxative activity too. This comprehensive report is targeted to enlighten the versatile applications of Surfactants in drug delivery, vaccine formulation, Cancer Treatment, Therapeutic and cosmetic Pharmaceutical Sciences and prevention of pulmonary failure due to COVID-19.

New, Biocompatible, Chitosan-Gelled Microemulsions Based on Essential Oils and Sucrose Esters as Nanocarriers for Topical Delivery of Fluconazole

Biocompatible gel microemulsions containing natural origin excipients are promising nanocarrier systems for the safe and effective topical application of hydrophobic drugs, including antifungals. Recently, to improve fluconazole skin permeation, tolerability and therapeutic efficacy, we developed topical biocompatible microemulsions based on cinnamon, oregano or clove essential oil (CIN, ORG or CLV) as the oil phase and sucrose laurate (D1216) or sucrose palmitate (D1616) as surfactants, excipients also possessing intrinsic antifungal activity. To follow up this research, this study aimed to improve the adhesiveness of respective fluconazole microemulsions using chitosan (a biopolymer with intrinsic antifungal activity) as gellator and to evaluate the formulation variables' effect (composition and concentration of essential oil, sucrose ester structure) on the gel microemulsions' (MEGELs) properties. All MEGELs were evaluated for drug content, pH, rheological behavior, viscosity, spreadability, in vitro drug release and skin permeation and antifungal activity. The results showed that formulation variables determined distinctive changes in the MEGELs' properties, which were nevertheless in accordance with official requirements for semisolid preparations. The highest flux and release rate values and large diameters of the fungal growth inhibition zone were produced by formulations MEGEL-FZ-D1616-CIN 10%, MEGEL-FZ-D1216-CIN 10% and MEGEL-FZ-D1616-ORG 10%. In conclusion, these MEGELs were demonstrated to be effective platforms for fluconazole topical delivery.

Analytical Strategies to Analyze the Oxidation Products of Phytosterols, and Formulation-Based Approaches to Reduce Their Generation

Phytosterols are a class of lipid molecules present in plants that are structurally similar to cholesterol and have been widely utilized as cholesterol-lowering agents. However, the susceptibility of phytosterols to oxidation has led to concerns regarding their safety and tolerability. Phytosterol oxidation products (POPs) present in a variety of enriched and non-enriched foods can show pro-atherogenic and pro-inflammatory properties. Therefore, it is crucial to screen and analyze various phytosterol-containing products for the presence of POPs and ultimately design or modify phytosterols in such a way that prevents the generation of POPs and yet maintains their pharmacological activity. The main approaches for the analysis of POPs include the use of mass spectrometry (MS) linked to a suitable separation technique, notably gas chromatography (GC). However, liquid chromatography (LC)-MS has the potential to simplify the analysis due to the elimination of any derivatization step, usually required for GC-MS. To reduce the transformation of phytosterols to their oxidized counterparts, formulation strategies can theoretically be adopted, including the use of microemulsions, microcapsules, micelles, nanoparticles, and liposomes. In addition, co-formulation with antioxidants, such as tocopherols, may prove useful in substantially preventing POP generation. The main objectives of this review article are to evaluate the various analytical strategies that have been adopted for analyzing them. In addition, formulation approaches that can prevent the generation of these oxidation products are proposed.

Recent advances in topical carriers of anti-fungal agents

Fungal skin infections are the most common global issue for skin health. Fungal infections are often treated by topical or systemic anti-fungal therapy. Topical fungal therapy is usually preferred because of their targeted therapy and fewer side effects. Advanced topical carriers because of their distinct structural and functional features, overcome biopharmaceutical challenges associated with conventional drug delivery systems like poor retention and low bioavailability. Literature evidence indicated topical nanocarriers loaded with anti-fungal agents display superior therapeutic response with minimum toxicity. Nanocarriers often used for topical anti-fungal medication includes Solid-Lipid nanoparticles, Microemulsions, Liposomes, Niosomes, Microsponge, Nanogel, Nanoemulsion, Micelles etc. This review summarizes recent advances in novel strategies employed in topical carriers to improve the therapeutic performance of anti-fungal drugs.

In Vitro Skin Permeation Methodology for Over-The-Counter Topical Dermatologic Products

For topically applied over-the-counter (OTC) products, the association of unwanted systemic exposure and adverse events may be difficult to ascertain without a recognition or determination of in vivo absorption. Evaluation of skin permeability using a validated in vitro permeation methodology can provide important information for both initial formulation selection and reformulation during the product life cycle. Additionally, a comparison of permeation rates between formulations using a validated methodology could reduce the number of nonclinical studies needed as part of reformulation. However, many in vitro permeation tests (IVPTs) have produced results with high variability and low reproducibility between study sites. It is unclear if this is due to a lack of a standardized protocol, or lack of control of multiple key experimental factors including skin source, preparation, receptor fluid, and study design. This review presents the authors perspective on the potential regulatory utility of IVPT and proposes steps to improve the accuracy and reproducibility of IVPT. The focus of this review is on topical dermatologic drugs with an initial emphasis on the OTC marketplace where reformulations are more common.

Design and Development of Lidocaine Microemulsions for Transdermal Delivery

Topical administration is a preferable choice for local anesthetic delivery. Microemulsions have shown great effectiveness for transdermal transport of lidocaine. However, fabrication of microemulsions containing highly concentrated lidocaine (10%) to provide an extended local anesthetic effect is still a challenge. This study investigated the feasibility of using microemulsions for transdermal delivery of a high dosage of lidocaine (10%). At first, eutectic mixtures by kneading lidocaine with thymol were tailored to form a lipophilic solution, then the mixtures were readily incorporated into the oil phase of microemulsions after addition of proper surfactants and cosurfactants. The physicochemical properties, the skin permeation, local anesthetic efficacy, and the irritation experiment of the developed microemulsions were evaluated. The optimum composition was as follows: 12% of ethyl oleate as oil phase, 28% of the mixed surfactant, and cosurfactant (polyoxyl 15 hydroxystearate and ethanol) and 60% of the aqueous phase. The average particle size was about 13 nm. The transmission electron microscope (TEM) studies revealed almost homogeneous spherical globules without aggregation. The Fourier-transform infrared spectroscopy (FTIR) results highlighted the drugs homogeneously dispersed in the microemulsions. In vitro skin permeation and in vivo anesthesia effect evaluation indicated that microemulsions can enhance and extend the anesthetic effect of lidocaine. The irritable results indicated that the microemulsions had the better biocompatibility and the negligible influence on the dermal. Therefore, incorporating the eutectic mixtures into microemulsions could be proposed as an attractive choice and a promising transdermal delivery strategy for the future topical anesthetic therapy.

Microemulsion and Microporation Effects on the Genistein Permeation Across Dermatomed Human Skin

This study reports the microemulsion (ME) effects on the permeation of genistein across normal (intact) and microporated human skin. The genistein formulation was optimized to know the stable ME region in the pseudo-ternary phase diagrams and to maximize the skin permeation and retention of genistein. The phase diagrams were constructed with different oil phases, surfactants, and their combinations. The influence of formulation factors on the permeation through intact and microporated human skin was determined. Based on its wide ME region, as well as permeation enhancement effects, oleic acid was used as an oil phase with various surfactants and co-surfactants to further maximize the ME region and skin permeation. The water content in the formulation played an important role in the ME stability, droplet size, and flux of genistein. For example, the ME with 20% water exhibited 4- and 9-fold higher flux as compared to the ME base (no water) and aqueous suspension, respectively. Likewise, this formulation had demonstrated 2- and 4-fold higher skin retention as compared to the ME base (no water) and aqueous suspension, respectively. The skin microporation did not significantly increase the skin permeation of genistein from ME formulations. The ME composition, water content, and to a lesser extent the ME particle size played a role in improving the skin permeation and retention of genistein.

Biomedical applications of microemulsion through dermal and transdermal route

Microemulsions are thermodynamically stable, transparent, colloidal drug carrier system extensively used by the scientists for effective drug delivery across the skin. It is a spontaneous isotropic mixture of lipophilic and hydrophilic substances stabilized by suitable surfactant and co-surfactant. The easy fabrication, long-term stability, enhanced solubilization, biocompatibility, skin-friendly appearance and affinity for both the hydrophilic and lipophilic drug substances make it superior for skin drug delivery over the other carrier systems. The topical administration of most of the active compounds is impaired by limited skin permeability due to the presence of skin barriers. In this sequence, the microemulsion represents a cost-effective and convenient drug carrier system which successfully delivers the drug to and across the skin. In the present review work, we compiled various attempts made in last 20 years, utilizing the microemulsion for dermal and transdermal delivery of various drugs. The review emphasizes the potency of microemulsion for topical and transdermal drug delivery and its effect on drug permeability.

Fatty Acid Based Microemulsions to Combat Ophthalmia Neonatorum Caused by Neisseria gonorrhoeae and Staphylococcus aureus

The bacterial species Neisseria gonorrhoeae (N. gonorrhoeae) and Staphylococcus aureus (S. aureus) are amongst the main microorganisms that cause ophthalmia neonatorum. The current treatment involves the use of various antibiotics such as ciprofloxacin, cephalosporin, ceftriaxone and cefotaxime. However, this treatment strategy is becoming more ineffective due to the antibiotic resistance in N. gonorrhoeae. The current study explores the potential use of fatty acid based microemulsions (ME) to prevent N. gonorrhoeae and S. aureus infections in new-borns' eyes without harmful side effects such as corneal or conjunctiva irritation. Pseudo-ternary phase diagrams were constructed to evaluate microemulsion regions and six different α-linolenic acid based microemulsions were prepared. The prepared formulations were characterized for α-linolenic acid content, size, transparency, zeta potential, Polarized light Microscopy, antimicrobial activity and ex vivo ocular toxicity. The mean droplet size of the ME formulations was in the range of 190.4 to 350.5 nm and polydispersity index (PDI) values were in the range of 0.102 to 0.561. All formulations were found stable upon storage for at least 8 weeks. In addition, self-diffusion coefficients determined by nuclear magnetic resonance (NMR) reflected that the diffusability of water increased at higher than 30% w/w water, while that of fatty acids and surfactants was in reverse. The antimicrobial efficacy of microemulsions was determined against N. gonorrhoeae and S. aureus. It was concluded that all microemulsions have strong antimicrobial effects against N. gonorrhoeae and S. aureus. Finally, bovine corneal opacity permeability (BCOP) and hen's egg chorioallantoic (HET-CAM) tests results showed that all microemulsion formulations were not strong ocular irritants.

Design and Development of Repaglinide Microemulsion Gel for Transdermal Delivery

Microemulsion formulation of repaglinide, a BCS class II hypoglycemic agent with limited oral bioavailability, was developed considering its solubility in various oils, surfactants, and cosurfactants. The pseudo-ternary phase diagrams for microemulsion regions were constructed by water titration method at K _m 1:1 and characterized for optical birefringence, percentage transmittance, pH, refractive index, globule size, zeta potential, viscosity, drug content, and thermodynamic stability. To enhance the drug permeation and residence time, the optimized microemulsions having mean globule size of 36.15 ± 9.89 nm was gelled with xanthan gum. The developed microemulsion-based gel was characterized for globule size, zeta potential, pH, and drug content. All evaluation parameters upon gelling were found to be satisfactory. Ex vivo permeability study across rat skin demonstrated higher steady-state flux (P < 0.05) for microemulsion of repaglinide in comparison to the repaglinide microemulsion gel. At the end of 24 h, the cumulative drug permeation from microemulsion and microemulsion gel was found to be 229.19 ± 24.34 and 180.84 ± 17.40 μg/cm², respectively. The microemulsion formulation showed 12.30-fold increase in flux as compared to drug suspension with highest enhancement ratio (E _r ) of 12.36. Whereas microemulsion gel exhibited 10.97-fold increase in flux (with highest E _r , 11.78) as compared to repaglinide (RPG) suspension. In vivo efficacy study was performed in normal Sprague-Dawley rats by using oral glucose tolerance test. Results of RPG transdermal microemulsion gel demonstrated remarkable advantage over orally administered RPG by reducing the glucose level in controlled manner. Hence, it could be a new, alternative dosage form for effective therapy of type 2 diabetes mellitus.

Fatty acid microemulsion for the treatment of neonatal conjunctivitis: quantification, characterisation and evaluation of antimicrobial activity

Fatty acids (FAs) are used by many organisms as defence mechanism against virulent bacteria. The high safety profile and broad spectrum of activity make them potential alternatives to currently used topical antibiotics for the treatment of eye infections in neonates. The current study utilised a Design of Experiment approach to optimise the quantification of five fatty acids namely; lauric acid, tridecanoic acid, myristoleic acid, palmitoleic acid and α-linolenic acid. The significance of the influence of the experimental parameters such as volume of catalyst, volume of n-hexane, incubation temperature, incubation time and the number of extraction steps on derivatisation was established by statistical screening with a factorial approach. Derivatisation was confirmed using attenuated total reflectance infrared (ATR) and 1H NMR spectrum. A gas chromatographic method (GC-FID) was developed and validated according to ICH guidelines for the identification and quantification of fatty acids. The results were found to be linear over the concentration range studied with coefficient of variation greater than 0.99 and high recovery values and low intra-day and inter-day variation values for all FAs. Then, different α-linolenic acid-based microemulsions (MEs) were prepared using Tween 80 as surfactant, polyethylene glycol 400 (PEG 400) as co surfactant and water as aqueous phase. The developed GC method was used to quantify the FA content in ME formulations. The results indicated that the developed GC method is very effective to quantify the FA content in the ME formulations. The antimicrobial efficacy of FA-based MEs were tested against Staphylococcus aureus. It was concluded that the FA-based MEs have strong antimicrobial effect against S. aureus.

Self-Nanoemulsifying Drug Delivery System of Coenzyme (Q10) with Improved Dissolution, Bioavailability, and Protective Efficiency on Liver Fibrosis

The aim of our investigation is to develop and characterize self-nanoemulsifying drug delivery systems (SNEDDS) of CoQ₁₀ to improve its water solubility, dissolution rate, and bioavailability, and then evaluate its biochemical and physiological effect on liver cirrhosis in rats compared with CoQ₁₀ powder. SNEDDS are isotropic and thermodynamically stable mixture of oil, surfactant, co-surfactant, and drug that form an oil/water nanoemulsion when added to aqueous phases with soft agitation. Upon administration, self-nanoemulsifying system becomes in contact with gastrointestinal fluid and forms o/w nanoemulsion by the aid of gastrointestinal motility. When the nanoemulsion is formed in the gastrointestinal tract, it presents the drug in a solubilized form inside small nano-sized droplets that provide a large surface area for enhancing the drug release and absorption. Solubility of CoQ₁₀ in various oils, surfactants, and co-surfactants were studied to identify the components of SNEDDS; pseudo-ternary phase diagrams were plotted to identify the efficient self-emulsifying regions. CoQ₁₀-loaded SNEDDS were prepared using isopropyl myristate as oil; Cremophor El, Labrasol, or Tween80 as surfactant; and Transcutol as co-surfactant. The amount of CoQ₁₀ in each vehicle was 3%. The formulations that passed thermostability evaluation test were assessed for particle size analysis, morphological characterization, refractive index, zeta potential, viscosity, electroconductivity, drug release profile, as well as ex vivo permeability. Pharmacokinetics and hepatoprotective efficiency of the optimized SNEDDS of CoQ₁₀ compared with CoQ₁₀ suspension were performed. Results showed that all optimized formulae have the ability to form a good and stable nanoemulsion when diluted with water; the mean droplet size of all formulae was in the nanometric range (11.7-13.5 nm) with optimum polydispersity index values (0.2-0.21). All formulae showed negative zeta potential (-11.3 to -17.2), and maximum drug loading efficiency. One hundred percent of CoQ₁₀ was released from most formulae within 30 min. One hundred percent of CoQ₁₀ was permeated from all formulae through 10 h. The pharmacokinetic study in rabbits revealed a significant increase in bioavailability of CoQ₁₀ SNEDDS to 2.1-fold compared with CoQ₁₀ suspension after oral administration. Comparative effect of the optimized formulae on acute liver injury compared with CoQ₁₀ powder was also studied; it was found that all the liver biochemical markers as alanine transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (ALP), total protein (TP), and albumin were significantly improved at p < 0.05. Also, histochemical and histopthological studies confirm the biochemical results. Our results suggest the potential use of SNEDDS to increase the solubility of liphophilic drug as poorly water-soluble CoQ₁₀ and improve its oral absorption, so it can be more efficient to improve liver damage compared to CoQ₁₀ powder. These results demonstrated that CoQ₁₀ SNEDDS inhibited thioacetamide (TAA)-induced liver fibrosis mainly through suppression of collagen production.

Alkyl Protocatechuate-Loaded Nanostructured Lipid Systems as a Treatment Strategy for Paracoccidioides brasiliensis and Paracoccidioides lutzii In Vitro

Dodecyl protocatechuate (dodecyl) is a derivative of protocatechuic acid (3,4-dihydroxybenzoic acid) that possesses anti-oxidant and antifungal properties. Nanostructured lipid systems (NLS) can potentiate the action of many antifungal agents, reducing the required dose and side effects by improving their activity. This work aimed to evaluate dodecyl protocatechuate loaded into a NLS (NLS+dodecyl) as a strategy for the treatment of Paracoccidioides brasiliensis and P. lutzii in vitro. Antifungal activity against P. brasiliensis and P. lutzii was evaluated using the microdilution technique. NLS+dodecyl showed high antifungal activity with a minimum inhibitory concentration ranging from 0.06 to 0.03 μg/mL; 4- to 16-fold higher than that of free dodecyl. NLS+dodecyl was able to inhibit fungal adhesion of the extracellular artificial matrix proteins (laminin and fibronectin), resulting in 82.4 and 81% inhibition, respectively, an increase of 8–17% compared with free dodecyl. These findings corroborate previous results demonstrating 65 and 74% inhibition of fungal adhesion in pulmonary fibroblast cells by dodecyl and NLS+dodecyl, respectively, representing a 9% increase in inhibition for NLS+dodecyl. Subsequently, cytotoxicity was evaluated using the 0.4% sulforhodamine B assay. NLS+dodecyl did not exhibit cytotoxicity in MRC5 (human pneumocyte) and HepG2 (human hepatic carcinoma) cells, thus increasing the selectivity index for NLS+dodecyl. In addition, cytotoxicity was evaluated in vivo using the Caenorhabditis elegans model; neither dodecyl nor NLS+dodecyl exhibited any toxic effects. Taken together, these results suggest that NLS can be used as a strategy to improve the activity of dodecyl against P. brasiliensis and P. lutzii because it improves antifungal activity, increases the inhibition of fungal adhesion in lung cells and the extracellular matrix in vitro, and does not exhibit any toxicity both in vitro and in vivo.

Improved Method for Solid Lipid Nanoparticle Preparation Based on Hot Microemulsions: Preparation, Characterization, Cytotoxicity, and Hemocompatibility Evaluation

The ease of application and no requirement of extra energy input make the microemulsion method favorable for solid lipid nanoparticles (SLNs) production. Very limited data are available to date on preparation of SLNs from pre-screened microemulsion phase diagrams. The purpose of this study was to investigate the microemulsion formation area with solid lipids using hot ternary phase diagrams at elevated temperatures and to use selected microemulsions for SLN production. Also, we aimed to characterize obtained SLNs in terms of physicochemical properties, in vitro cell toxicity, and hemolysis. Phase diagrams of solid lipids were screened at elevated temperatures and oil-in-water microemulsion regions were determined. Microemulsions were selected, and SLNs were produced by modification of the microemulsion dilution method and characterized in terms of visual appearance, turbidity, particle size, and zeta potential. Cytotoxicity of nanoparticles was tested on L929 mouse skin fibroblast cells. Hemolytic potential was assessed in vitro using freshly isolated erythrocytes. The phase diagram screening and the modified hot microemulsion dilution method enabled production of SLNs with particle size below 100 nm. We found evidence that the solid lipids in the SLNs produced by the new method remain in supercooled liquid state. Nanoparticles prepared by the new method exhibit lower toxicity on L929 cells and have lower hemolytic potential than the formulations prepared by direct mixing of the components. The method can be used to prepare SLNs with controllable composition and small particle size below 100 nm. These SLNs are low toxic and can be used for drug delivery purposes.

Novel microemulsion-based gel formulation of tazarotene for therapy of acne

The objective of this study was to develop and evaluate a novel microemulsion based gel formulation containing tazarotene for targeted topical therapy of acne. Psudoternary phase diagrams were constructed to obtain the concentration range of oil, surfactant, and co-surfactant for microemulsion formation. The optimized microemulsion formulation containing 0.05% tazarotene was formulated by spontaneous microemulsification method consisting of 10% Labrafac CC, mixed emulsifiers 15% Labrasol-Cremophor-RH 40 (1:1), 15% Capmul MCM, and 60% distilled water (w/w) as an external phase. All plain and tazarotene-loaded microemulsions were clear and showed physicochemical parameters for desired topical delivery and stability. The permeation profiles of tazarotene through rat skin from optimized microemulsion formulation followed the Higuchi model for controlled permeation. Microemulsion-based gel was prepared by incorporating Carbopol®971P NF in optimized microemulsion formulation having suitable skin permeation rate and skin uptake. Microemulsion-based gel showed desired physicochemical parameters and demonstrated advantage over marketed formulation in improving the skin tolerability of tazarotene indicating its potential in improving its topical delivery. The developed microemulsion-based gel may be a potential drug delivery vehicle for targeted topical delivery of tazarotene in the treatment of acne.

Design and Formulation of Optimized Microemulsions for Dermal Delivery of Resveratrol

The objective of this study was to formulate optimal formulations of microemulsions (MEs) and evaluate their feasibility for delivery of resveratrol into human skin ex vivo. Oil-in-water MEs were formulated using surfactant (S) PEG-8 caprylic/capric glycerides and cosurfactant (CoS) polyglyceryl-6-isostearate. Ethyl oleate was used as an oily phase. MEs were formulated using 5 : 1, 6 : 1, and 7 : 1 surfactant and cosurfactant (S : CoS) weight ratios. Pseudoternary phase diagrams were constructed and optimal compositions of MEs were obtained using Design Expert software. Mean droplet size for optimized ME formulations was determined to be 68.54 ± 1.18 nm, 66.08 ± 0.16 nm, and 66.66 ± 0.56 nm for systems with S : CoS weight ratios 5 : 1, 6 : 1, and 7 : 1, respectively. Resveratrol loading resulted in mean droplet size increase. The distribution of droplet size between fractions changed during storage of formulated MEs. Results demonstrated the increase of number of droplets and relative surface area when S : CoS weight ratios were 6 : 1 and 7 : 1 and the decrease when S : CoS weight ratio was 5 : 1. The highest penetration of resveratrol into the skin ex vivo was determined from ME with S : CoS weight ratio 5 : 1. It was demonstrated that all MEs were similar in their ability to deliver resveratrol into the skin ex vivo.

Optimizing the dermal accumulation of a tazarotene microemulsion using skin deposition modeling

CONTEXT

It is well known that microemulsions are mainly utilized for their transdermal rather than their dermal drug delivery potential due to their low viscosity, and the presence of penetration enhancing surfactants and co-surfactants.

OBJECTIVE

Applying quality by design (QbD) principles, a tazarotene microemulsion formulation for local skin delivery was optimized by creating a control space.

MATERIALS AND METHODS

Critical formulation factors (CFF) were oil, surfactant/co-surfactant (SAA/CoS), and water percentages. Critical quality attributes (CQA) were globular size, microemulsion viscosity, tazarotene skin deposition, permeation, and local accumulation efficiency index.

RESULTS AND DISCUSSION

Increasing oil percentage increased globular size, while the opposite occurred regarding SAA/CoS, (p = 0.001). Microemulsion viscosity was reduced by increasing oil and water percentages (p < 0.05), due to the inherent high viscosity of the utilized SAA/CoS. Drug deposition in the skin was reduced by increasing SAA/CoS due to the increased hydrophilicity and viscosity of the system, but increased by increasing water due to hydration effect (p = 0.009). Models with very good fit were generated, predicting the effect of CFF on globular size, microemulsion viscosity, and drug deposition. A combination of 40% oil and 45% SAA/CoS showed the maximum drug deposition of 75.1%. Clinical skin irritation study showed that the aforementioned formula was safe for topical use.

CONCLUSION

This article suggests that applying QbD tools such as experimental design is an efficient tool for drug product design.

In Vitro Intestinal Permeability Studies and Pharmacokinetic Evaluation of Famotidine Microemulsion for Oral Delivery

The absolute bioavailability of famotidine after oral administration is about 40-45% and absorbance only in the initial part of small intestine may be due to low intestinal permeability. Hence, an olive oil based microemulsion formulation with Tween-80 as surfactant and PEG-400 as cosurfactant was developed by using water titration method with the aim of enhancing the intestinal permeability as well as oral bioavailability. In vitro drug permeation in intestine after 8 h for all formulations varied from 30.42% to 78.39% and most of the formulations showed enhanced permeation compared to pure drug (48.92%). Famotidine microemulsion exhibited the higher absorption and C max⁡ achieved from the optimized famotidine formulation (456.20 ng·h/ml) was higher than the standard (126.80 ng·h/mL). It was found that AUC0-24 h obtained from the optimized famotidine test formulation (3023.5 ng·h/mL) was significantly higher than the standard famotidine (1663.3 ng·h/mL). F-1 demonstrated a longer (6 h) T max⁡ compared with standard drug (2 h) and sustained the release of drug over 24 h. The bioavailability of F-1 formulation was about 1.8-fold higher than that of standard drug. This enhanced bioavailability of famotidine loaded in microemulsion system might be due to increased intestinal permeability.

A critical appraisal of microemulsions for drug delivery: part II

Microemulsions are thermodynamically stable, optically transparent isotropic solutions of oil and water successfully formulated by using a combination of suitable surfactant and cosurfactant. The solubilization power of microemulsions for lipophilic, hydrophilic and amphiphilic solutes form a viable approach for enhancing the bioavailability of hydrophobic drugs and percutaneous permeation of poorly permeable drugs, mainly due to the large area per volume ratio available for mass transfer. Microemulsions have emerged as novel vehicles for drug delivery due to their versatile applications. They allow sustained release for topical, oral, nasal, intravenous, ocular, parenteral and other administration routes of drugs. They also offer a relevant application platform for improving target specificity, therapeutic activity, and reducing toxicity of drugs.

Nanoemulsion containing dapsone for topical administration: a study of in vitro release and epidermal permeation

BACKGROUND

Topical administration of dapsone can be an alternative route for treatment of leprosy and can also provide new therapeutic applications for an established drug. However, the physicochemical properties of dapsone make it difficult to incorporate into conventional formulations. The current study was directed toward developing a stable nanoemulsion that contains dapsone which can be adapted for topical use.

METHODS

Nanoemulsions were prepared using isopropyl myristate or n-methyl-pyrrolidone as the oil phase, and characterized according to their mean droplet size, conductivity, refractive index, pH, drug content, and stability. The in vitro release of dapsone and its ability to permeate the epidermis were also evaluated.

RESULTS

Physicochemical characterization demonstrated that nanosystems were formed, which had a uniform droplet distribution and a pH compatible with the skin surface. Use of n-methyl-pyrrolidone provided a greater nanoemulsion region and higher solubilization of dapsone, and increased the in vitro release rate when compared with a nanoemulsion prepared using isopropyl myristate. However, use of isopropyl myristate promoted an increase in in vitro epidermal permeation that followed the Higuchi model. This demonstrates the ability of a nanosystem to influence permeation of dapsone through the skin barrier. Furthermore, the nanoemulsions developed and evaluated here had ideal physicochemical stability over a 3-month period.

CONCLUSION

Incorporation of dapsone into a nanoemulsion may be a promising system for enabling topical delivery of dapsone, while minimizing skin permeation, for the treatment of acne. The method developed here used isopropyl myristate as the oil phase, and promoted permeation of dapsone through the skin barrier for the treatment of leprosy upon use of n-methyl-pyrrolidone as the oil phase.

Formulation and evaluation of microemulsion-based hydrogel for topical delivery

Background:

The purpose of this study was to develop microemulsion-based hydrogel formulation for topical delivery of bifonazole with an objective to increase the solubility and skin permeability of the drug.

Materials and Methods:

Oleic acid was screened as the oil phase of microemulsions, due to a good solubilizing capacity of the microemulison systems. The pseudo-ternary phase diagrams for microemulsion regions were constructed using oleic acid as the oil, Tween 80 as the surfactant and isopropyl alcohol (IPA) as the cosurfactant. Various microemulsion formulations were prepared and optimized by 3² factorial design on the basis of percentage (%) transmittance, globule size, zeta potential, drug release, and skin permeability. The abilities of various microemulsions to deliver bifonazole through the skin were evaluated ex vivo using Franz diffusion cells fitted with rat skins. The Hydroxy Propyl Methyl Cellulose (HPMC) K100 M as a gel matrix was used to construct the microemulsion-based hydrogel for improving the viscosity of microemulsion for topical administration. The optimized microemulsion-based hydrogel was evaluated for viscosity, spreadability, skin irritancy, skin permeability, stability, and antifungal activity by comparing it with marketed bifonazole cream.

Results:

The mechanism of drug release from microemulsion-based hydrogel was observed to follow zero order kinetics. The studied optimized microemulsion-based hydrogel showed a good stability over the period of 3 months. Average globule size of optimized microemulsion (F5) was found to be 18.98 nm, zeta potential was found to be -5.56 mv, and permeability of drug from microemulsion within 8 h was observed 84%. The antifungal activity of microemulsion-based hydrogel was found to be comparable with marketed cream.

Conclusion:

The results indicate that the studied microemulsion-based hydrogel (F5) has a potential for sustained action of drug release and it may act as promising vehicle for topical delivery of ibuprofen.

Transfersomes: a novel vesicular carrier for enhanced transdermal delivery of sertraline: development, characterization, and performance evaluation

The aim of the present study was to investigate transfersomes as a transdermal delivery system for the poorly soluble drug, sertraline, in order to overcome the troubles associated with its oral delivery. Different transfersomal formulations were prepared with non-ionic surfactant (span 80), soya lecithin, and carbopol 940 by the rotary evaporation sonication method. The prepared formulations were characterized for light microscopy, particle size analysis, drug entrapment, turbidity, drug content, rheological studies, in vitro release, ex vivo permeation, and stability studies. The optimized formulation was evaluated for in vivo studies using the modified forced swim model test. FTIR studies showed compatibility of the drug with excipients. The result revealed that sertraline in all of the formulations was successfully entrapped with uniform drug content. Transfersomal gel containing 1.6% of the drug and 20% of span 80 was concluded to be the optimized formulation (EL-SP4), as it showed maximum drug entrapment (90.4±0.15%) and cumulative percent drug release(73.8%). The ex vivo permeation profile of EL-SP4 was compared with the transfersomal suspension, control gel, and drug solution. The transfersomal gel showed a significantly higher (p<0.05) cumulative amount of drug permeation and flux along with lower lag time than the drug solution and drug gel. It also owed to better applicability due to the higher viscosity imparted by the gel rather than the transfersomal suspension, and no skin irritation was observed. The modified forced swim test in mice revealed that the transfersomal gel had better antidepressant activity as compared to the control gel. Thus, the study substantiated that the transfersomal gel can be used as a feasible alternative to the conventional formulations of sertraline with advanced permeation characteristics for transdermal application.

Ondansetron HCl Microemulsions for Transdermal Delivery: Formulation and In Vitro Skin Permeation

Ondansetron HCl delivery through oral route suffers due to its low bioavailability due to first-pass metabolism. Therefore, the microemulsion-based transdermal delivery may be a better substitute for it. The pseudoternary phase diagrams were constructed to determine compositions of microemulsions, and ondansetron HCl microemulsions for transdermal delivery were developed using isopropyl myristate or oleic acid as the oil phase, Tween 80 as the surfactant, and isopropyl alcohol as the cosurfactant evaluated for in vitro skin permeation through excised porcine skin. The in vitro skin permeation from these formulated microemulsions was sustained over 24 hours. The microemulsion F-8 (contained 10% of isopropyl myristate as oil phase, 8% of aqueous phase, and 82% of surfactant phase containing Tween 80 and isopropyl alcohol, 3 : 1) showed the highest permeation flux of 0.284 ± 0.003 μg/cm(2)/hour. All these microemulsions followed the Korsmeyer-Peppas model (R(2) = 0.971  to  0.998) with non-Fickian, "anomalous" mechanism over a period of 24 hours.

Microemulsion-based gel of terbinafine for the treatment of onychomycosis: optimization of formulation using D-optimal design

The aim of the present investigation was to evaluate microemulsion as a vehicle for dermal drug delivery and to develop microemulsion-based gel of terbinafine for the treatment of onychomycosis. D-optimal mixture experimental design was adopted to optimize the amount of oil (X(1)), Smix (mixture of surfactant and cosurfactant; X(2)) and water (X(3)) in the microemulsion. The formulations were assessed for globule size (in nanometers; Y(1)) and solubility of drug in microemulsion (in milligrams per milliliter; Y(2)). The microemulsion containing 5.75% oil, 53.75% surfactant-cosurfactant mixture and 40.5% water was selected as the optimized batch. The globule size and solubility of the optimized batch were 18.14 nm and 43.71 mg/ml, respectively. Transmission electron microscopy showed that globules were spherical in shape. Drug containing microemulsion was converted into gel employing 0.75% w/w carbopol 934P. The optimized gel showed better penetration and retention in the human cadaver skin as compared to the commercial cream. The cumulative amount of terbinafine permeated after 12 h was 244.65 ± 18.43 μg cm(-2) which was three times more than the selected commercial cream. Terbinafine microemulsion in the gel form showed better activity against Candida albicans and Trichophyton rubrum than the commercial cream. It was concluded that drug-loaded gel could be a promising formulation for effective treatment of onychomycosis.

Preparation, characterization, pharmacokinetics and tissue distribution of solid lipid nanoparticles loaded with tetrandrine

Tetrandrine (TET) is a poorly water-soluble bisbenzylisoquinoline alkaloid. In this study, TET solid lipid nanoparticles (SLNs) were prepared by a melt-emulsification and ultrasonication technique. Precirol(®) ATO 5, glyceryl monostearate, and stearic acid were used as the lipid matrix for the SLNs, while Lipoid E80, Pluronic F68, and sodium deoxycholate were used as emulsifying and stabilizing agents. The physicochemical characteristics of the TET-SLNs were investigated when it was found that the mean particle size and zeta potential of the TET-SLNs were 134 ± 1.3 nm and -53.8 ± 1.7 mV, respectively, and the entrapment efficiency (EE) was 89.57% ± 0.39%. Differential scanning calorimetry indicated that TET was in an amorphous state in SLNs. TET-SLNs exhibited a higher release rate at a lower pH and a lower release rate at a higher pH. The release pattern of the TET-SLNs followed the Weibull model. The pharmacokinetics of TET-SLNs after intravenous administration to male rats was studied. TET-SLN resulted in a higher plasma concentration and lower clearance. The biodistribution study indicated that TET-SLN showed a high uptake in reticuloendothelial system organs. In conclusion, TET-SLNs with a small particle size, and high EE, can be produced by the method described in this study. The SLN system is a promising approach for the intravenous delivery of tetrandrine.

Improving the isotretinoin photostability by incorporating in microemulsion matrix

The present paper demonstrates the increased photostability of isotretinoin when loaded in microemulsion. The photodegradation of isotretinoin, in methanol and microemulsion formulation was studied under direct sun light. The photodegradation process was monitored by UV spectrophotometry. In methanol solution, isotretinoin undergoes complete photodegradation just within a few minutes of light exposure. Isotretinoin incorporated in microemulsion formulation showed an increased stability in comparison to the methanol solutions. In particular for isotretinoin, a residual concentration of 75% was still present after a light irradiance versus a residual value of just 16% measured at the same time in methanol solution. Further, degradation kinetic parameters of isotretinoin-loaded microemulsion formulation were demonstrated increase isotretinoin half-life about five-times in comparison with a methanol solution under a direct sun light.