Development and Evaluation of Release Equivalent Sustained Release Formulation of Dextromethorphan Hbr Using Simple Technology

Dextromethorphan HBr is a synthetic antitussive compound. Biological half life of this drug is 2 to 4 hours. Due to its shorter half life the dose is upto 4 times a day, thereby reducing patient compliance. Thus to reduce the dose frequency and to improve the patient compliance sustained release tablets of freely water soluble Dextromethorphan HBr. was formulated with non-swellable waxy polymer Compritol888 by dry granulation method. The matrix tablets of Dextromethorphan HBr were prepared by direct compression of granules, physical mixture of drug and polymer was found compatible after comparative study for three months. Matrix tablets were evaluated for hardness, friability and weight variation. This tablet was capsulated with loading dose of drug. Invitro drug release study was performed using USPXXIII apparatus (basket type) in HCl pH 1.2 for two hrs and in phosphate buffer pH 6.8 for remaining 10 hrs. Dissolution study showed that polymers can sustain the release of drug for up to 12 hrs. Comparison of Invitro release of the Dextromethorphan HBr with existing sustained release suspension (Delsym) clearly indicated the advantage of present formulation in terms of release equivalence, patient compliance by using simple dry granulation method. The equivalent formulation was developed using dry granulation method which showed advantages in the terms of patient compliance, safety, and better transportation over existing suspension formulation. Difference factor (f1) and similarity factor (f2) was used as a statistical method in this work.