FORMULATION AND EVALUATION OF MUCOADHESIVE BILAYER TABLET CONTAINING GLICLAZIDE AND METFORMIN HCL

Bi-layer tablet is a new era for successful development of controlled release formulation along with various features to provide successful drug delivery. The objective of the study was to formulate and evaluate Gliclazide-Metformin HCl bilayer tablet containing Gliclazide in immediate release (IR) layer and Metformin HCl in sustained release (SR) layer. Gliclazide-Metformin HCl bilayer tablets were prepared and evaluated by ex vivo and in vitro studies. A total of 4 formulations (F1-F4) were prepared by direct compression using 4 different mucoadhesive polymers (carbopol 971, HPMC K4M, HPMC K15M and HPMC K100M) in each formulation. Formulated tablets were evaluated for ex vivo mucoadhesive strength, ex vivo mucoadhesion time, and in vitro drug release. F1 containing carbopol 971 demonstrated prolonged ex vivo mucoadhesion with highest mucoadhesive strength (detachment force =1.118N) and longest residence time (6.2hrs). On the other hand, better release retardation from SR layer was observed for F4 with HPMC K100M as drug career (61.63% Metformin HCl release in 8 hrs). Drug release from IR layer complied with compendial requirements and followed zero order kinetics. Sustained release from F1 and F2 followed Higuchi (R2 = 0.993 and 0.991, respectively) and Korsmeyer- Peppas was found best fitted for F3 and F4 (R2 = 0.994 and 0.996, respectively). Non-Fickian diffusion/class-II transport (n > 0.45) was the predominant mechanism of drug release for all the formulations. The results suggest that a mixture of carbopol 971 and HPMC K100M- ratio of the individual ingredient to be determined by mix design- will better serve the purpose.