The role of calcium bentonite as a delivery carrier for an antihypertensive drug

Abstract

Clays and clay minerals have been widely used as carriers for drug delivery due to their properties such as cation exchange capacity, adsorption, and biocompatibility. In this study, a new drug release system was obtained by adsorption of amiloride hydrochloride on calcium bentonite (Ca2+-Bent). The ‘in vitro’ release tests were evaluated in the gastric (SGF, pH 1.2), and intestinal (SIF, pH 7.4) simulated fluids. The drug intercalation in clay mineral was confirmed by X-ray diffraction and transmission electronic microscopy, obtaining basal space of 1.59 nm in the hybrid. Zeta potential measurements, infrared spectroscopy, X-ray photoelectron spectroscopy, XRF and calcium release supported the mechanism of drug/clay mineral interaction. The amount of loaded amiloride on Ca2+-Bent was 192.3 mg per gram of solid and characterizations suggested the contribution of both ion exchange and Ca2+ drug complexation in the process. The Ca2+-Bent/amiloride hybrid exhibited a drug-controlled release and reached a release of 53.4% and 38.9% in 11 h in SGF and SIF fluids, respectively. MTT evaluation indicated that system was biocompatible. Ca2+-Bent behaved as a promisor for the drug delivery system.