Various Formulation Variables Effecting Floatation Behaviour of Single Unit Gastroretentive Capsules of Ofloxacin

Abstract

Objective: Objective of the present study was to prepare simple single unit gastro-retentive capsules of ofloxacin with the aim to have the gastric retention of the system for longer periods of time (12h) and to study the effect of various polymers on floating behaviour of such single unit gastroretentive capsules of ofloxacin. Methods:The method used for the preparation of gastro-retentive capsules was a simple physical blending of various low-density hydrophilic polymers alone and in combination with hydrophobic polymers and filling into capsules. These capsules were then subjected to in vitro floatation and matrix integrity study in 0.1N HCl using static volume beaker method and the United States pharmacopoeia (USP) type II dissolution apparatus method at 100rpm.Results: Two grades of hydroxypropyl methylcellulose (HPMC) K4M and K15M used were found suitable for the purpose. Results showed that increase in HPMC level increased colloidal gel barrier strength along with matrix integrity with consequently improved buoyancy. Lactose which was added as release rate modifier decreased matrix integrity and buoyancy. Eudragit a hydrophobic polymer was added so as to have intact, the buoyant formulation for 12 h with desired drug release characteristics. The addition of eudragit enhanced matrix integrity and floatation time to certain levels but higher levels showed negative results. Floatation time of more than 16 h was observed in the formulations containing 2:1 ratio of HPMC K15M and eudragit respectively. 3 2 Conclusion:The study concludes that eudragit S100 a hydrophobic polymer increased floatation time of the formulated capsules with all the three levels of HPMC K15M, but at the same time eudragit level should not exceed HPMC, while lactose a release rate enhancer decreased matrix integrity/floatation time of the formulated capsules.factorial design was used to study the effect of various formulation variables on buoyancy and matrix integrity. Formulations containing zero level of HPMC were found buoyant for more than 12 h with all levels of eudragit S100 (i.e.,-1, 0,+1 level). It was also observed that matrix integrity consequently buoyancy increased with increase in eudragit with all levels of HPMC.