In vitro release kinetics of drugs from silica aerogels loaded by different modes and conditions using supercritical CO2

Abstract

The present work aims to investigate release kinetics of a model drug (benzoic acid) loaded on silica aerogels from supercritical carbon dioxide (scCO2). Effects of loading parameters on release kinetics have been analysed for two modes of drug loading: (i) only adsorption (mode I) at varying contact times and initial concentrations in scCO2 and (ii) adsorption followed by precipitation (mode II) at varying initial concentrations and depressurization times. It is observed that drug loaded by mode II releases faster than mode I, both much faster than neat BA, though releases faster for both modes at lower initial concentration. Drug precipitated during fast depressurization releases faster than that during slow depressurization. Storage does not affect release kinetics for mode I at lower initial concentration, whereas storage slows down release for mode II. It is inferred that release is significantly enhanced and can be altered by varying the mode and loading conditions.