Cationic microemulsion of voriconazole for the treatment of fungal keratitis: in vitro and in vivo evaluation

Aim: This investigation aimed to develop a voriconazole-loaded chitosan-coated cationic microemulsion (CVME) to treat fungal keratitis. Methods: Microemulsions were prepared using water titration, and the optimized microemulsion was coated with chitosan to prepare CVME. The physicochemical parameters, ocular irritation potential, in vitro antifungal efficacy and in vitro release studies were performed. The in vivo antifungal efficacy study was conducted in a fungal infection-induced rabbit eye model. Results: The developed CVME displayed acceptable physicochemical properties and excellent mucoadhesive behavior and showed a sustained release profile. Ex vivo and in vivo studies concluded that higher permeability and improved antifungal efficacy were observed for CVME than drug suspension (DS). Conclusion: The prepared CVME7 is a viable alternative to treating fungal keratitis with existing approaches.

Microemulsions vs chitosan derivative-coated microemulsions for dermal delivery of 8-methoxypsoralen

Background

8-methoxypsoralen (8-MOP) is one of the most commonly utilized drugs in psoralen-ultraviolet A therapy for treatment of vitiligo. However, poor skin retention and systemic side effects limit the clinical application of 8-MOP.

Methods

Microemulsions (MEs) and chitosan derivative-coated 8-MOP MEs were developed and compared for dermal delivery of 8-MOP. Ex vivo skin retention/permeation study was performed to select the ME formulation with the highest retention:permeation ratio. Four different chitosan-coated MEs were prepared and compared with the ME formulation for their ability to distribute 8-MOP in the skin.

Results

Among various ME formulations developed, a formulation containing 2.9% ethyl oleate, 17.2% Cromophor EL35, 8.6% ethanol and 71.3% water showed the highest ex vivo skin retention:permeation ratio (1.98). Of four chitosan-coated MEs prepared, carboxymethyl chitosan-coated MEs (CC-MEs) and hydroxypropyl chitosan-coated MEs (HC-MEs) showed higher ex vivo skin retention:permeation ratio (1.46 and 1.84). and were selected for in vivo pharmacokinetic study. AUC_skin (0–12 h) for 8-MOP MEs (4578.56 h·ng·mL⁻¹) was higher than HC-MEs (3422.47 h·ng·mL⁻¹), CC-MEs (2808.51 h·ng·mL⁻¹) and tincture (1500.16 h·ng·mL⁻¹). Also, AUCplasma (0–12 h) for MEs (39.35±13.90 h·ng·mL⁻¹) was significantly lower than HC-MEs (66.32 h·ng·mL⁻¹), CC-MEs (59.70 h·ng·mL⁻¹) and tincture (73.02 h·ng·mL⁻¹).

Conclusion

These combined results suggested that the MEs developed could be a promising and safe alternative for targeted skin delivery of 8-MOP.