A Review on Recent Controlled Release Strategies for Oral Drug Delivery of Repaglinide (a BCS Class II Drug)

Repaglinide is an antidiabetic drug that works by stimulating insulin secretion from pancreatic beta cells. Repaglinide is practically insoluble in water with a water solubility of 34 μg/mL at 37°C, and it has a high absorption rate from the gastrointestinal tract following oral administration since the log P value of repaglinide is 3.97. The low aqueous solubility and the high permeability of repaglinide represent a typical behavior for drugs that belong to class II Biopharmaceutical Classification System (BCS II). Managing type-2 diabetes mellitus with repaglinide is considered a burdensome therapy, as it requires frequent dosing of repaglinide before each meal to maintain its therapeutic plasma concentration due to its short plasma half-life of approximately one hour. Hence the present review aims to discuss thoroughly the various approaches investigated in recent years to develop drug delivery systems that improve oral delivery of repaglinide, including nanoemulsions, solid lipid nanoparticles, nanostructured lipid carriers, sustained-release hydrophilic matrix, floating microspheres, and nanocomposites.