Recent developments in formulation design for improving oral bioavailability of curcumin: A review

Curcumin, a yellow-orange substance that is extracted from the spice turmeric (Curcuma longa, Zinziberaceae), has been attributed with a wide range of pharmacological activities for the prevention and treatment of several disease conditions such as arthritis, hypertension, diabetes, Alzheimer's, antibacterial and cancer to name a few. However, its potential for use as an orally delivered medicinal product is hindered by its poor solubility and bioavailability. The low oral bioavailability of curcumin is caused by several factors including low aqueous solubility, poor intestinal permeability, unstable at alkaline pH and rapid metabolism. To improve curcumin's poor oral bioavailability, different formulation strategies such as incorporation into nanoparticles, liposomes, micelles, micro/nano-emulsions and solid dispersions as well as co-administration with piperine have been investigated in both animal models as well as human supplementation studies. In this review, novel formulations of curcumin for oral delivery that were developed in recent years are reviewed and discussed.