Development and pharmacokinetic evaluation of a curcumin co-solvent formulation

Poor solubility and bioavailability are limiting factors for the clinical application of curcumin. The objective of the current study was to develop a liquid formulation with increased solubility and systemic bioavailability. A co-solvent formulation with increased solubility of 20 mg/ml was developed and optimized. Pharmacokinetics of the new formulation were evaluated using rats receiving 30 mg/kg intravenous or 50 mg/kg intramuscular administration of co-solvent formulation, compared against a control group receiving 50 mg/kg of curcumin in DMSO through intramuscular injection. Plasma concentrations were measured using liquid chromatography-mass spectrometry (LC-MS/MS). The intramuscular injection of formulation resulted in 30% absolute bioavailability and provided sustained release by maintaining plasma concentrations of curcumin above 240 ng/ml for up to 4 h. A 29-fold increase in the maximum plasma concentration (Cmax) and 28-fold increase in the area under the plasma concentration versus time curve (AUC) led to a 28-fold increase in relative bioavailability for the co-solvent formulation. The findings reported here suggest that the clinical application of curcumin can be better-exploited through an intramuscular administration of the co-solvent formulation developed in the present study.