Formulation and evaluation of hydroxypropylmethylcellulose-dicyclomine microsponges for colon targeted drug delivery: In vitro and in vivo evaluation.

OBJECTIVE The objective of present study was to design novel colon targeted delivery of dicyclomine Hydrochloride (DCH) microsponges. METHODS Microsponges (MS1-MS4) based on different ratios of hydroxypropylmethylcellulose (HPMC) and DCH was prepared by quasi-emulsion solvent diffusion method. Micro-sponges were analyzed by determining percent yield, encapsulation efficiency, drug content, drug-polymer compatibility and thermal stability. Kinetic analysis of thermal stability data was done by Chang method, Friedman method and Broido method. In vitro dissolution study was carried out at pH 1.2, pH 6.8 and pH 7.4 at different time intervals. RESULTS Results showed that there was no chemical interaction between DCH and HPMC in all microsponge formulations. Production yield, drug content and encapsulation efficiency were enhanced on increasing the drug-polymer ratio. Thermal stability of all the micro-sponges was greater than that of pure drug. In vitro drug release was decreased on increasing the polymer concentration at different pH levels. The newly prepared micro-sponges based on HPMC were confirmed as a promising means of colon targeted delivery of DCH. An HPLC method was developed and validated for the bioequivalence study of newly designed microsponges. Pharmacokinetics parameters were calculated using linear trapezoidal method after single oral administration of microsponges in white albino rabbits. Pharmacokinetics results indicate an enhancement in the value of t1/2, tmax, Cmax and AUC0-t of DCH in the microsponges as compared to standard DCH showing enhanced bioavailability of drug after microsponges formation. CONCLUSION The current study shows a new approach for colon specific delivery of DCH based on microsponges.