The flow-through cell as an in vitro dissolution discriminative tool for evaluation of gliclazide solid dispersions

Abstract

Gliclazide (GLZ) is used to treat type II diabetes mellitus. It is a poorly soluble drug with variable bioavailability. The aim of this study was to improve GLZ solubility and dissolution rate by mixing or co-grinding with different polymers (PEG 4000, PEG 8000, MCC, HPMC E15 and alginates). Dissolution of two commercial products was carried out for comparison. GLZ solubility in phosphate buffer (pH 7.4) showed that grinding of GLZ considerably increased its solubility while, other polymers did not affect GLZ solubility. Flow-through cell (FTC) dissolution apparatus with two patterns of GLZ powder loading were utilized to achieve sensitive and reproducible dissolution data. Results revealed that distribution of untreated and ground GLZ powder with large volume of glass beads gave the best dissolution profiles in terms of rapid onset of dissolution (Q5min) and dissolution efficiency (DE60min). The best excipient among all was PEG (4000 and 8000), where GLZ physical mixture (PM) enhanced the dissolution rate without co-grinding to form solid dispersion (CSD). The highest dissolution rate and extent were obtained from GLZ:PEG 4000 (1:5) PM, where about 45.88 % was dissolved after 5 min and DE60min was 74.18%.