Preparation and evaluation of alcohol-alkaline-treated rice starch as a tablet disintegrant

Purpose: To prepare and characterize alcohol-alkaline modified rice starch (MRS) as a disintegrant for tablets. Methods: The preparation of MRS was carried out using 3 M NaOH and 40 % ethanol solution. Characterization carried out for MRS include morphology, swelling capacity, thermal and pasting properties. Direct-compressed tablets (DCT) containing either propranolol hydrochloride (PPNL) or hydrochlorothiazide (HCTZ) were evaluated for hardness, friability, disintegration time and drug release. Results: The microstructure of MRS was different in shape and dimension from that of rice starch (RS). The absence of gelatinization endotherm and FT-IR spectral peak for MRS correlated with change in MRS structure and arrangement. MRS showed significantly higher swelling capacity (p < 0.05) than RS, and also proved to be a disintegrant in DCT. The disintegration time of the tablets containing MRS was lower in the presence of large particles (3.55 ± 0.56 min); high content of MRS (1.03 ± 0.06 min); low content of lubricant (3.16 ± 0.44 min); water soluble filler (1.55 ± 0.16 min for Super-tab®); and model drug (0.84 ± 0.09 min for HCTZ) (p < 0.05). Conclusion: MRS exhibits improved water solubility and swelling capacity compared with RS, and is thus a good disintegrant for direct-compressed tablet formulations, especially in the presence of water insoluble fillers.