Topical Biocompatible Fluconazole-Loaded Microemulsions Based on Essential Oils and Sucrose Esters: Formulation Design Based on Pseudo-Ternary Phase Diagrams and Physicochemical Characterization

Formulation and evaluation of fluconazole emulgels for potential treatment of vaginal candidiasis

Localised treatment of vaginal candidiasis could improve the therapeutic outcomes of patients with vaginal candidiasis as well as reduce drug dosage and dosing interval. The aim of the research project was to develop fluconazole emulgel formulations, and evaluate their physicochemical, drug release, antifungal, safety, and stability profile, for potential treatment of vaginal candidiasis. Xanthan gum and HPMC E5LV-based fluconazole emulgels were prepared using the spontaneous emulsification method and their physicochemical properties, drug content, drug release profile, anti-fungal activity against Candida albicans, in vivo vaginal biocompatibility and stability profile were evaluated using standard protocols. The fluconazole emulgels exhibited satisfactory properties: pH: 5.2-5.4; spreadability: 1.6-2.5 cm; apparent viscosity: 85-314 cP; zone of inhibition against Candida albicans: 22-38 mm; drug content: 91-102 %, and vaginal biocompatibility. All the studied fluconazole emulgels exhibited controlled fluconazole release over 6 h and their drug release kinetics fitted well with Korsmeyer-Peppas model. HPMC-based emulgels exhibited unsatisfactory real-time stability profile. To our knowledge, this is the first report where xanthan gum and HPMC E5LV-based fluconazole emulgels have been studied for possible treatment of vaginal candidiasis. Xanthan gum-based fluconazole emulgels are promising drug formulations that could reduce the drug dosage and dosing frequency. In addition, they could serve as alternative dosage forms to Flucos® gel.

Development and Characterization of New Miconazole-Based Microemulsions for Buccal Delivery by Implementing a Full Factorial Design Modeling

This research aimed to develop miconazole-based microemulsions using oleic acid as a natural lipophilic phase and a stabilizer mixture comprising Tween 20 and PEG 400 to solubilize miconazole as an antifungal agent known for its activity in oral candidiasis and to improve its bioavailability. The formulation and preparation process was combined with a mathematical approach using a 23-full factorial plan. Fluid and gel-like microemulsions were obtained and analyzed considering pH, conductivity, and refractive index, followed by extensive analyses focused on droplet size, zeta potential, rheological behavior, and goniometry. In vitro release tests were performed to assess their biopharmaceutical characteristics. Independent variables coded X1-Oleic acid (%, w/w), X2-Tween 20 (%, w/w), and X3-PEG 400 (%, w/w) were analyzed in relationship with three main outputs like mean droplet size, work of adhesion, and diffusion coefficient by combining statistical tools with response surface methodology. The microemulsion containing miconazole base-2%, oleic acid-5%, Tween 20-40%, PEG 400-20%, and water-33% exhibited a mean droplet size of 119.6 nm, a work of adhesion of 71.98 mN/m, a diffusion coefficient of 2.11·10-5 cm2/s, and together with remarked attributes of two gel-like systems formulated with higher oil concentrations, modeled the final optimization step of microemulsions as potential systems for buccal delivery.

Co-emulsified Alginate-Eudragit Nanoparticles: Potential Carriers for Localized and Time-defined Release of Tenofovir in the Female Genital Tract

This research aimed to explore the possibilities of Eudragit S100 (ES100) and sodium alginate as carriers for tenofovir disoproxil fumarate (TDF) in the female genital tract. Alginate and alginate-ES100 nanoparticles were prepared using the ionic gelation and emulsion/gelation complexation method, respectively. The nanocarriers were tested using morphological, physicochemical, in vitro drug release, and cytotoxicity analyses. In SEM and TEM images, the presence of spherical and uniformly distributed nanoparticles was revealed. The FTIR spectrum showed that alginate and calcium chloride interacted due to ionic bonds linking divalent calcium ions and the -COO- of alginate groups. Alginate and ES100 interacted via the ester C=O amide stretching. The results obtained from XRD and DSC, on the other hand, revealed a favorable interaction between sodium alginate and ES100 polymers, as evidenced by the crystallization peaks observed. Under experimental design analysis and optimization, overall size distribution profiles ranged from 134.9 to 228.0 nm, while zeta potential results showed stable nanoparticles (-17.8 to -38.4 MV). The optimal formulation exhibited a maximum cumulative in vitro release of 72% (pH 4.2) up to 96 h. The cytotoxicity tests revealed the safety of TDF-loaded nanoparticles on vaginal epithelial cells at concentrations of 0.025 mg/mL, 0.5 mg/mL, and 1 mg/mL for 72 h. These results indicated that alginate-ES100 nanoparticles have the potential to preserve and sustain the release of the TDF drug in the FGT. The future goal is to develop a low-dose non-toxic microbicide that can be administered long term in the vagina to cater to both pregnant and non-pregnant HIV patients.

Insight into the Inclusion Complexation of Fluconazole with Sulfonatocalix[4]naphthalene in Aqueous Solution, Solid-State, and Its Antimycotic Activity

The study aims to assess the interaction between fluconazole and sulfonatocalix[4]naphthalene towards enhancing its dissolution performance and antimycotic activity. A solubility study was carried out at different pH conditions, and the results revealed the formation of a 1:1 molar ratio fluconazole-sulfonatocalix[4]naphthalene inclusion complex with an A_L type phase solubility diagrams. The solid powder systems of fluconazole-sulfonatocalix[4]naphthalene were prepared using kneaded and co-evaporation techniques and physical mixtures. DCS, PXRD, TGA-DTG, FT-IR, and in vitro dissolution performance characterize the prepared systems. According to physicochemical characterization, the co-evaporation approach produces an amorphous inclusion complex of the drug inside the cavity of sulfonatocalix[4]naphthalene. The co-evaporate product significantly increased the drug dissolution rate up to 93 ± 1.77% within 10 min, unlike other prepared solid powders. The antimycotic activity showed an increase substantially (p ≤ 0.05, t-test) antimycotic activity of fluconazole co-evaporate mixture with sulfonatocalix[4]naphthalene compared with fluconazole alone against clinical strains of Candida albicans and Candida glabrata. In conclusion, sulfonatocalix[4]naphthalene could be considered an efficient complexing agent for fluconazole to enhance its aqueous solubility, dissolution performance, and antimycotic activity.

Insights from a Box-Behnken Optimization Study of Microemulsions with Salicylic Acid for Acne Therapy

The present study brings to attention a method to develop salicylic acid-based oil in water (O/W) microemulsions using a tensioactive system based on Tween 80, lecithin, and propylene glycol (PG), enriched with a vegetable oat oil phase and hyaluronic acid. The systems were physically characterized and the Quality by design approach was applied to optimize the attributes of microemulsions using Box-Behnken modeling, combined with response surface methodology. For this purpose, a 33 fractional factorial design was selected. The effect of independent variables namely X1: Tween 80/PG (%), X2: Lecithin (%), X3: Oil phase (%) was analyzed considering their impact upon the internal structure and evaluated parameters chosen as dependent factors: viscosity, mean droplet size, and work of adhesion. A high viscosity, a low droplet size, an adequate wettability-with a reduced mechanical work-and clarity were considered as desirable for the optimal systems. It was found that the optimal microemulsion which complied with the established conditions was based on: Tween 80/PG 40%, lecithin 0.3%, oat oil 2%, salicylic acid 0.5%, hyaluronic acid 1%, and water 56.2%. The response surface methodology was considered an appropriate tool to explain the impact of formulation factors on the physical properties of microemulsions, offering a complex pattern in the assessment of stability and quality attributes for the optimized formulation.

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.