Effect of particle morphology and pore size on the release kinetics of ephedrine from mesoporous MCM-41 materials

Abstract

Ephedrine was loaded onto siliceous mesoporous materials of different pore sizes, and the corresponding drug release into simulated body fluid at pH 7.4 and 37 °C was measured against time over a period of 72 h. The mesoporous materials designated MCM-41(CN) were prepared at different pore sizes using a self-assembly mechanism. The pore size was controlled by the use of alkyltrimethylammonium bromide (CNTAB) surfactants having different alkyl chain lengths (C10, C12, and C14). The three mesoporous materials showed good ephedrine-loading capacities from dry ethanolic solutions, which slightly increased with the pore size of MCM-41(CN). From the drug release profiles, the overall release of ephedrine followed the order: MCM-41(C12) > MCM-41(C14) > MCM-41(C10), with the release of ephedrine attaining 92% of the drug load from MCM-41(C12). Ephedrine release approached 60% of the drug load in 6 h and 92% in 20 h. The results of in vitro release kinetics indicate that pore size is not the only factor affecting ephedrine release, but also pore channel length and overall particle morphology.