No abstract

This study investigated the formation of composite particles of chitosan (CS) and theophylline (TPH) via supercritical assisted atomization (SAA) using aqueous ethanol (50%, v/v) as the solvent and supercritical CO 2 as the spraying medium. According to XRD, DSC, and FTIR analyses, the crystal form of the SAA-treated TPH from the as-received TPH was unchanged. The effect of different mass ratios of CS to TPH on the in vitro release of TPH showed that the dissolution of the highly water-soluble TPH was retarded when included in the composite particles and could be controlled by the mass ratio of the component in the SAA process. The in vitro dissolution data showed a good fit with the Peppas-Sahlin model, which was used to conclude that the drug release from the composite particles resulted from a combination of drug diffusion and relaxation of the polymer. As the mass ratio of CS to TPH increased, the mechanism relating to polymer relaxation became crucial in the TPH-CS composite particles.