Mesoporous silica materials with different structures as the carriers for antimicrobial agent. Modeling of chlorhexidine adsorption and release

摘要

The present study was aimed to evaluate the potential of five different mesoporous materials (SBA-15, compressed SBA-15, PHTS, SBA-16, MCF) as the carrier for chlorhexidine adsorption and release. All the materials were characterized by large specific surface area similar to 700 m(2), however their pore volume and pore geometry were substantially different. Langmuir, Freundlich and Dubinin-Radushkevich isotherm models were applied to experimental equilibrium data of chlorhexidine adsorption onto examined mesoporous materials. In all experiments, the commercial silica was used as a reference material. The highest maximum adsorption capacity calculated from the Langmuir model of 416.7 and 357.1 mg/g was observed for SBA-15 and MCF silicas, respectively. Meanwhile, SBA-16 material was characterized by the lowest maximum adsorption capacity of 85.5 mg/g. To compare the chlorhexidine dissolution profiles, four release models were tested such as Higuchi, Korsmeyer-Peppas, Baker-Lonsdale and Weibull. Mesoporous matrices with increased micropore fraction (PHTS, SBA-16) exhibited markedly prolonged release of chlorhexidine as compared to other silicas. The time interval necessary to dissolve 63.2% of chlorhexidine present in the formulation calculated from the Weibull model (t(63.2%)) reached the highest values of 203.5 and 308.5 h for PHTS and SBA-16 silicas, respectively. (C) 2015 Elsevier B.V. All rights reserved.