Development and Evaluation of Floating Sustained Release Bilayer Tablets Containing Dothiepin HCl

Bilayer floating tablets of Dothiepin HCL were developed by direct compression method. Immediate release layer contains 30 mg of drug and super disintegrant sodium starch glycolate, serves the purpose of loading dose. Sustained release layer contained HPMC K4M, natural polymers like xanthan gum, guar gum, karaya gum release the drug for 12 hours’ time. Sodium bicarbonate and citric acid are used to produce effervescence. Floating lag time of optimized tablet is 92 sec, whereas floating duration is more than 12 hours. FTIR results revealed that there was no interaction between drug and HPMC K4M / xanthan gum. The post compression parameters of developed tablets were found to be satisfactory. In this study, it was confirmed that the formulations containing HPMC K4M, have shown better floating properties and finally the formulation containing a combination of HPMC K4M and xanthan gum in 3:1 ratio, has exhibited decent sustained drug release properties. The release kinetics of optimized formulation prepared with the combination of HPMC K4M and xanthan gum followed zero order kinetics.