Properties Study on Hydroxypropyl Methylcellulose Trimellitate

Synthesized a novel kind of enteric-coating material-HPMCT. Its structure and application properties such as dissolving ability in different organic solvent, pH sensibility, coating technical properties and dissolution rate in buffer solution(pH=6.86)were analyzed by IR and UV. The results indicated that ethanol/methylene chloride, acetone/ethanol/water, acetone/ethanol and ethanol /water were all good solvent systems for the HPMCT; the pH sensibility value range of the HPMCT is 3.8~4.0, the HPMCT can dissolve rapidly in buffer solution(pH=6.86), achieving tight, smooth and having metallic brightness coating without plasticizer. Dissolution rate of the coated tablet in buffer solution(pH=6.86) in 20 minutes were 92.60%, which meet the necessity of enteric coating material.