DESIGN AND OPTIMIZATION OF EXPANDABLE GASTRORETENTIVE PATCH OF METRONIDAZOLE FOR HELICOBACTER PYLORI INFECTION MANAGEMENTAbstract
The aim of the present research was to develop and optimize novel expandable gastro retentive formulation of metronidazole to give local action for the management of Helicobacter pylori infection. The formulation contained a drug-loaded sandwich patch prepared by solvent casting method folded into a hard gelatin capsule. Metronidazole being needle shape crystals soluble in 0.1 N HCl, but after drying, the formulation show bursting effect in first 1 h. To avoid this drug-loaded middle layer containing Xanthan gum and HPMC E15 as release retardants was sandwiched between baking layers of HPMC E15. Drug loaded middle layer was subjected to 32 full factorial design with concentration of HPMC E15 (X1) and Xanthan gum (X2) as independent variables and release of the metronidazole at 1st h and at 4th h as Responses. According to 32 full factorial design 9 batches were prepared and evaluated for thickness, folding endurance, mucoadhesion, drug content and % drug release. The thickness of formulations F1 to F6 was found to be in the range of 0.266 to 0.352 mm. Folding endurance, Mucoadhesion, and % of drug content of F1-F9 were found to be between 100 to 250, 2.2 to 4.2 N and 98.35% to 99.65% respectively. In-vitro drug release of F1-F9 batches showed bursting effect in F1-F4 batches while optimized batch F6 showed 99.89% release in 12 h. HPMC E15: Xanthan gum with 1.5%: 0.8% concentration (F6) was found to be optimized with good folding-endurance, mucoadhesion, and sustained release till 12 h.