Abstract:

Objective To investigate in vitro release profile of extended-release layer containing niacin and immediate-release layer containing simvastatin in compound tablets. Methods Extended-release layer of the tablets were subjected to an in vitro release in different dissolution media (water, 0.1mol/L HCl, pH6.8 phosphate buffer) for determining niacin by UV, and niacin extended-release tablets BENYUE on sale served as the control. 0.01mol/L phosphate buffer (pH7.0, containing 0.5% SLS) was used as the dissolution medium for determining simvastatin by HPLC. ResultsRelease rate of niacin in an extended-release layer ranged from 10% to 30% in 3h, 40% to 60% in 9?h, and over 75% in 16h, which could accord with quality. Release curves of the two products could accord with the Higuchi equation (r＞0.99). The similarity factor f2 was between 50 and 100. Release rate of simvastatin in an immediate-release layer was up to 80% in 45 minutes. Conclusion Release rates of niacin in the experimental formulation and reference product BENYUE are similar. Simvastatin in an immediate-release layer accords with quality in release rate.

Key words: Niacin； Simvastatin； Doublelayer Tablets； In Vitro Release