Preparation, In-vitro and In-vivo characterization of gliclazide / hydroxypropyl B-CD complexes and correlation with hypoglycemic effect

ABSTRACT

The effect of HP Beta-CD complexes on both pharmacokinetic and hypoglycemic parameters of gliclazide was evaluated and correli with in-vitro dissolution. The study involves the preparation of solid inclusion complexes of gliclazide [Gz] with hydroxypropyl beta-cyclodextrin [HP Beta-CD] using different techniques [recrystallization, kneading, neutralization and physical mixtures]. The prepared binary systems were subjected to X-ray diffraction [XRD] and infrared spectroscopy [IR]. Their dissolution behavior was evaluated using USP XXIV method. The dissolution performance of the various complexes appeared to be related to the preparation method of the solid system and showed significant enhancement for the kneaded and recrystallized systems. The plasma levels of Gz following oral administration of HP Beta-CD kneaded and recrystallized complexes to beagle dogs were found to be greater than those after administration of the drug alone. Pure Gz, recrystallized and kneaded complexes produced maximum plasma levels [Cmax] of 8.05, 16.00 and 16.30 micro/ml at 4.5, 4.3 and 3.2hours, respectively. The areas under the plasma concentration curve [AUC] of kneaded and recrystallized complexes were found to be 2.33 and 2.04 folds greater than that of Gz alone, respectively. The hypoglycemic activity was in the order of kneading > pure drug> recrystallization. The various measures of bioavailability correlated well with in-vitro tests, while neither in-vitro nor in-vivo adequately correlated with hypoglycenlic activity. In conclusion, recrystallized and kneaded complexes were the best in enhancing gliclazide dissolution characteristics and bioavailability. These enhancements have the potential of reducing inter-patient variability and decreasing the daily dose of Gz with little side effects