Preparation of Diatomite-Chitosan Composites for Loading and Release of Diphenhydramine HCl

Abstract

Diatomite ores have great potential as an adsorbent and drug carrier system due to their natural abundance, biocompatible, and high surface area. In the first stage of this study, raw diatomite ore was enriched by grinding and calcination processes. As a result of the enrichment process, the surface area was found to be 21.7 m2/g for raw diatomite and 75.1 m2/g for calcined diatomite. Subsequently, a series of diatomite-chitosan composites with different composition ratios were produced. Then, the loading (adsorption) performances of diphenhydramine hydrochloride (DPH), an antihistaminic agent, were investigated on the prepared composites. The highest loading capacity was 91.1 mg/g, and the lowest loading capacity was 48.8 mg/g in the prepared DPH-loaded formulations. After DPH loading studies, DPH release profiles (desorption) and release kinetics from composites were investigated. As a result of in vitro release studies, it was observed that formulations containing chitosan polymer had slower release than chitosan free formulations. It was determined that the formulations had a cumulative release in the 70-90% range, and the release processes were completed between 45-90 minutes. In vitro release profiles of the prepared formulations were compatible with Higuchi kinetics.