Controlled drug release of highly water-soluble pentoxifylline from time-limit disintegration-type wax matrix tablets.

A pulsatile drug release system with a dry-coated tablet containing pentoxifylline was investigated for controlling drug release in the gastrointestinal tract. The system consisted of a core tablet with disintegrator and outer layer, which obtained compression from the ground mixtures of pentoxifylline and behenic acid. Drug release from a dry-coated tablet was investigated at 37 degrees C in JPXII 2nd fluid at pH 6.8. The drug release from the outer layer was fitted to the Cobby model. The drug release from the wax matrix increased significantly after tablet distintegration; therefore, the drug release profiles showed typical sigmoidal curves. The disintegration time depended on the weight fraction of the core tablet, and the drug release rate after disintegration increased with increasing drug concentration in the core tablet. The relationship between the time required for 50% drug release and the disintegration time was linear, indicating that the drug release rate was controlled by regulating the disintegration time.