This study described the thermosensitive formulations composed of poloxamer mixtures for use as drug delivery platform via mucosal route. It also characterized the poloxamer mixtures' rheological, mechanical and mucoadhesive properties. Poloxamer (Plx) 407 and Plx 188 were used alone and together for preparing the mucosal drug delivery platform. The mixtures of Plx 407 and Plx 188 in ratio of 15:15 (F5); 15:20 (F6); 20:10 (F7) existed liquid at room temperature, but gelled at physiological temperature. Flow rheometry studies and oscillatory analysis of each formulation were performed at 20 ± 0.1°C and 37 ± 0.1°C. F5 and F7 formulations exhibited typical gel-type mechanical spectra (G' > G″) after the determined frequency value at 37°C whereas F6 behaved as weakly cross-linked gel. Texture profile analysis presented that F5 and F7 showed similar mechanical properties and can be used as base for mucosal dosage form. Mucoadhesion studies indicated the difference among the formulations and the effect of the mucosal surface on mucoadhesive properties. Mucin disc, bovine vaginal and buccal mucosa were used as mucosal platform for mucoadhesion studies. It is suggested that these investigations may be usefully combined to provide a more rational basis for selecting the ratio of Plx to prepare a topical thermosensitive drug delivery system for mucosal administration.

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The aim of the present study was to make a comparison of the in vitro release rate of diclofenac sodium (DS) from microemulsion (M) vehicles containing soybean oil, nonionic surfactants (Brij 58 and Span 80), and different alcohols (ethanol [E], isopropyl alcohol [I], and propanol [P]) as cosurfactant. The optimum surfactant:cosurfactant (S:CoS) weight ratios and microemulsion areas were detected by the aid of phase diagrams. Three microemulsion formulations were selected, and their physicochemical properties were examined for the pH, viscosity, and conductivity. According to the release rate of DS, M prepared with P showed the significantly highest flux value (0.059 ± 0.018 mg/cm 2 /h) among all formulations (P G .05). The conductivity results showed that DS-loaded microemulsions have higher conductivity values (18.8-20.2 microsiemens/cm) than unloaded formulations (16.9-17.9 microsiemens/cm), and loading DS into the formulation had no negative effect on system stability. Moreover, viscosity measurements were examined as a function of shear rate, and Newtonian fluid characterization was observed for each microemulsion system. All formulations had appropriate observed pH values varying from 6.70 to 6.85 for topical application. A skin irritation study was performed with microemulsions on human volunteers, and no visible reaction was observed with any of the formulations. In conclusion, M prepared with P may be a more appropriate formulation than the other 2 formulations studied as drug carrier for topical application.

Chitosan-based carriers have important potential applications for the administration of drugs. In the present study, topical gel formulations of terbinafine hydrochloride (T-HCl) were prepared using different types of chitosan at different molecular weight, and the antifungal inhibitory activity was evaluated to suggest an effective formulation for the treatment of fungal infections. The characteristics of gel formulations were determined with viscosity measurements and texture profile analysis. Stability studies were performed at different temperatures during 3 months. The ex vivo permeation properties were studied through rat skin by using Franz diffusion cells. The antifungal inhibitory activity of formulations on Candida species and filamentous fungi was also examined with agar-cup method. The microbiological assay was found suitable for determination of in vitro antifungal activity of T-HCl. A marketed product was used to compare the results. The antifungal activity of T-HCl significantly increased when it was introduced into the chitosan gels. A higher drug release and the highest zone of inhibition were obtained from gels prepared with the lowest molecular weight chitosan (Protasan UP CL 213) compared to that of other chitosan gels and marketed product. These results indicated the advantages of the suggested formulations for topical antifungal therapy against Candida species and filamentous fungi.