Preparation and in vivo pharmacokinetic evaluation of stable microemulsion system of cholecalciferol

The objectives of the study were to formulate stable oil-in-water microemulsion (ME) system of cholecalciferol, a lipophilic and unstable prohormone for bone health, and evaluate its pharmacokinetic profile in beagle dogs. ME system consisting of caprylic/capric triglyceride (Captex 355), propylene glycol esters of fatty acids (Capryol 90), and macrogol 15 hydroxystearate (Solutol HS15) was approximately 100 nm in size with polydispersity index < 0.3 and zeta potential of - 5 mV. Incorporation of the liable compound in the oil droplet markedly impeded its chemical degradation, maintaining drug content over 93% after 2 years storage under ambient condition (25 degrees C/60% RH). In an absorption study using beagle dogs (n = 6 per group), there were no significant (P > 0.05) differences in pharmacokinetic parameters between novel ME-based drink and conventional tablet dosage form. Therefore, novel ME-based drink could be used as a convenient way to provide cholecalciferol supplementation for patients with dysphagia.