EMBEDMENT TECHNIQUE: AN ALTERNATIVE TO WET GRANULATION FOR BETTER CONTROL OF RELEASE OF HIGHLY WATER SOLUBLE DRUGS–A CASE STUDY WITH DILTIAZEM HCl

Objective: Extending or controlling the release of highly water soluble drugs from matrix tablets is always a challenge. The research attempt was aimed to explore the embedment technique for the development of extended release (ER) matrix tablets of highly water soluble drugs by taking Diltiazem HCl as a model drug.Methods: The matrix tablets were developed through embedding the drug in the polymer matrix followed by compression using hydroxypropyl methylcellulose (HPMC) K 4000, Eudragit RS PO as drug release-retarding polymers. Matrix tablets from the optimized formulations (F5 & F11) were also prepared by wet granulation method for comparing the efficiency of both the techniques for controlling the drug release.Results: The results of the dissolution studies indicated that the drug release could be controlled only up to 16 h with HPMC K 4000 alone (formulation F5), but upon incorporation of Eudragit RS PO, the drug release was extended up to 24 h (formulation F11). The matrix tablets from the same formulations, F5 and F11, prepared by wet granulation technique showed the drug release only up to 12 h and 20 h respectively. The drug release from these formulations followed first–order kinetics. The mechanism was found to be almost Higuchi's diffusion along with some anomalous transport (non–Fickian diffusion).Conclusion: The embedding technique was found to be promising for the development of ER matrix tablets of highly water soluble drugs with lesser quantities of polymers.Â