Characterization and evaluation of different mesoporous silica kinds as carriers for the development of effective oral dosage forms of glibenclamide

Abstract

This work evaluated the suitability of various mesoporous silicas as carriers for developing an oral formulation endowed with improved dissolution properties of glibenclamide, hypoglycemic agent poorly water-soluble. The different silicas were examined for solid-state, morphology, and technological and physical-chemical properties (granulometry, specific surface area, wettability, water content, water activity, apparent density, flowability, compactability). A pairwise comparison allowed a ranking, by importance order, of the parameters examined and, for each parameter, a score was assigned to each silica type. Data statistical treatment (JMP software) indicated Neusilin®US2 and Syloid®XDP3150 as the best materials. Different loading methods were tested: physical mixing; addition of drug dissolved in a volatile solvent, subsequently evaporated; addition of drug dissolved in a solvent. Methods involving drug dissolution enabled drug amorphization and intimate dispersion within the silica porous structure. Dissolution tests indicated Syloid®XDP3150 as the most effective silica in enhancing drug dissolution properties, providing a release rate clearly faster than from commercial tablets. Drug amorphization, improved wettability, increased surface area of the drug, finely dispersed into the highly porous silica, were the main factors responsible for this finding. Moreover, the obtained results suggested that drug dissolution rate can be properly tuned, based on the suited choice of the silica type.