DESIGN AND EVALUATION OF BILAYER FLOATING TABLETS OF DILTIAZEM HCL

The present investigation concerns design and evaluation of bilayer floating tablets of Diltiazem HCl Diltiazem HCl is Class I drug, though its reported bioavailability is only 40 %. It is having very short half life of 3 to 4 hrs. Hence many sustained release formulations were developed for Diltiazem HCl. A direct compression method was used to formulate all batches. 32 factorial design was applied to study % cumulative drug release and hardness. Super disintigrants like Sodium starch glycolate was used for immediate release layer and HPMC K200 M, Xanthan gum like polymers were used in floating layer for sustain release layer.Optimisation study was performed by using design expert software. Successful formulation was developed having floating lag time as low as 14 sec and drug release was sustained up to 12 hrs. A biphasic drug release can be obtained by using bilayer tableting technology which involved compression of immediate and sustained release layer together. The variables HPMC K200M and Xanthan Gum evaluated in this study exhibited significant affected the release profile. Keywords: Bilayer floating tablets, Diltiazem HCl, HPMC K 200 M, Xanthan gum, % drug release.