Study of the influence of selected variables on the preparation of prolonged release bioadhesive vaginal carbohydrate microspheres using experimental design

Degradable polymer multiparticulate drug delivery overcomes many conventional systems shortcomings. To evaluate, using a multi-varied experimental design, the influence of the selected variables on the physicochemical properties of designed formulae to prepare sustained-release mucoadhesive fluconazole vaginal microspheres for the localized treatment of vulvovaginal candidiasis overcoming oral delivery drawbacks. The microspheres where prepared following the ionotropic gelation and extrusion method. Also, the effect of polymer combination was investigated. Microspheres were characterized using SEM and FTIR. Optimum conditions for the preparation process were found to be curing time (X1) = 4 h and drug concentration (X2) = 8 %. Binary-polymeric microspheres showed more extended release patterns compared to single-polymeric microspheres. Among the former, M5 (chitosan-polycarpophil) attained the most extended diffusion-controlled drug release (MDT = 5.68 h), the highest EE% (81.75 %) and good mucoadhesive properties according to its ability to interact with mucin. This study shows that simple modification of some crucial and efficient variables allows microsphere tailoring to fit the desired physicochemical properties.