Biocompatible nanoporous carbons as a carrier system for controlled release of cephalexin

Abstract

An ordered nanoporous carbon (ONC) was synthesized by the hard-template method and then superficially modified with amino groups from 3-aminopropyltrietoxisilane (ONC-A). Both carbons, ONC and ONC-A, were characterized and tested as carriers of a high-frequency dosing drug such as cephalexin (CFX). Density functional theory calculations were used to study the interactions between ONC and the amino groups of ONC-A and CFX. Finally, the biocompatibility of human colon carcinoma (Caco-2) cells and in vitro release kinetics at gastric and intestinal pH were evaluated. The results show that drug loading capacity was higher in ONC than in ONC-A, which was associated with a localized increase in adsorption energy and a decrease in the textural properties on the surface of the ONC-A sample. Both carbon materials showed cell viability above 80 %, even at high concentrations (1000 µg mL−1). The CFX release profiles of both carbons reached their maximum at 12 h, whereas the rapid release of pure CFX at gastric and intestinal pH was 30 min. The release mechanisms obeyed the Weibull model governed by Fickian diffusion, influenced by both porosity and functional groups in ONC and ONC-A.