Development and in vitro biopharmaceutical evaluation of a dihydroquercetin microemulsion

Dihydroquercetin (DHQ) is a readily available compound with a broad spectrum of biological activity that makes development of new drug forms based on this compound imperative. In particular, it exhibits capillary-protective, anti-oxidant, and anti-inflammatory effects. Microemulsions are promising systems for delivering drugs and can increase their biological availability and provide their controlled release. A water-in-oil microemulsion containing DHQ (2%), surfactant (Tween 80), cosurfactant (propyleneglycol), an oil phase (Labrafil M 1944 CS), and water was prepared. Physicochemical parameters (particle size, viscosity, refractive index, denisty, and pH) and the in vitro release of DHQ were studied by the paddle-over-disk method in systems modeling local transdermal application and the paddle method in systems modeling oral application. Release rate constants were calculated. The proposed microemulsion ensures uniform prolonged release of the active substance.