Pregelatinized glutinous rice starch as a sustained release agent for tablet preparations

The aim of this study was to modify the glutinous rice starch (GS) as a sustained release agent for tablet preparations. The GS slurry was physically modified by heat and then dried by spray drying. The pregelatinized GS (PGS) appeared in odorless fine white powder. Its flowability is extremely poor. The tablet containing PGS and propranolol HCl were prepared by wet granulation method. Less than 80% of propranolol HCl was released in the period of 10 h at the drug to PGS ratio of 1:2 and longer than 14 h at the ratios of 1:3 and 1:4. The higher the composition ratio of PGS, the slower the release of the drug. The mechanisms of drug release from the matrices were anomalous (non-Fickian) diffusion in both hydrochloric buffer (pH 1.2) and phosphate buffer media (pH 6.8). The compaction pressure in the range of 6.9–27.5 MPa does not affect the release of the drug from the matrices.