Assessment of the Physicochemical Properties and In Vitro Dissolution of Glibenclamide Tablets Marketed in Saudi Arabia

Glibenclamide (GBD), also known as glyburide, is an oral hypoglycemic of the sulfonylurea group that is frequently prescribed for the treatment of noninsulin dependent diabetes mellitus. The aim of this study was to assess the pharmaceutical quality of new formulations and four generic marketed glibenclamide tablets in Saudi Arabia in comparison with the innovator product (Daonil tablets). Friability, uniformity of dosage unit, disintegration, and in vitro drug release for the investigated products were determined. The friability was less than 1% for all products. The innovator and the tested products all passed the content uniformity test according to USP 34. The acceptance values ranged from 3.8 to 6.4. The disintegration time of all products in distilled water, ranging from 3 to 14 min, met USP requirements. In vitro release testing of innovator, new formulations, and generics was carried out in phosphate buffer pH 7.4 and pH 7.8, and in borate buffer pH 9.5. The similarity in dissolution profiles (f2) was assessed using the FDA recommended approach. The f2 factor increases with increasing pH from 7.4 to 9.5; pH 9.5 is optimum for correlation for some generics (Brands II, III, and IV), while pH 7.8 is optimum for Brand I. Formula IV exhibited a dissolution profile similar to that of the innovator and had the highest f2 similarity factor at pH 7.4.