In vitro release of theophylline from starch-based matrices prepared via high hydrostatic pressure treatment and autoclaving

Recent works have demonstrated that release behavior of bioactive compounds varies with the nature of the matrix regarding its chemical composition, morphology and surface properties. Starch matrices varying in amylose content (maize, sorghum, Hylon VII) or pure amylopectin ones (waxy maize, amaranth starch), containing theophylline (10 mg, 50 mg/0.5 g of starch), were obtained via high hydrostatic pressure treatment (650 MPa/9 min) and autoclaving (120 °C/20 min). Both the treatment used and drug dose affected the theophylline release profiles from the matrices studied. The profiles of amylopectin starch matrices satisfactorily fitted with selected mathematical models, indicating a controlled theophylline release. The principal component analysis confirmed substantial differences in drug release between the amylose and amylopectin matrices. The differences in matrix morphology, internal surface area and porosity (mesopore diameter, cumulative pore volume) between the matrices studied were found to be key factors affecting the theophylline dissolution.