Design and evaluation of glimepiride hydrogel for transdermal delivery.

The solubility of glimepiride (GM) was improved from 1.6 μg/mL to 22.0 mg/mL when GM and meglumine (MU) complexes were prepared. Therefore, transdermal hydrogels of GM Carbopol (GM-CP) and GM hydroxypropyl methylcellulose pullulan (GM-HPMC-Pu) were prepared successfully utilizing the improved drug solubility by GM-MU. Based on a single factor experiment and response surface methodology, two kinds of hydrogel formulations were optimized by drug release studies . The optimized GM-CP hydrogel was composed of GM, a mixture of azone and oleic acid (1:1, 2.6%, ) and carbopol 940 (1%, ). The GM-HPMC-Pu hydrogel was developed using GM, HPMC (3.5%, ), Pu (1.5%, ), glycerol (5%, ), azone (2.9%, ) and oleic acid (2.6%, ). The study of hydrogels was performed using rabbits. The results indicated that the drug could sustain release from GM-CP or GM-HPMC-Pu hydrogel and maintain the high plasma concentration for 48 h. Compared with commercial GM tablets, the relative bioavailability of GM-CP and GM-HPMC-Pu hydrogel reached 48% and 133%, respectively. Moreover, the drug release could well predict its absorption . There was a good correlation (≥0.966) in GM hydrogel between the drug release and transdermal absorption . Therefore, a novel GM hydrogel dosage form may be considered to design.