Preparation and solid state characterisation of co-crystals of etravirine engineered by fabricating with flavonoids as possible conformers

The following study was done to establish that etravirine, which is an anti-human immuno deficiency virus drug, when produced as co-crystals helps in improving its solubility. The produced cocrystals were also characterized. According to the Biopharmaceutical Classification System, etravirine is categorised in class IV category; that is; a drug having low permeability and solubility. Structurally, pharmaceutical co-crystals are homogeneous crystalline materials involving an active pharmaceutical ingredient and the conformer in precise stoichiometric amounts. Physicochemically stable co-crystals of etravirine were formed with rutin and piperine when prepared in 1:1 and 1:2 molar ratio by solvent evaporation method. Analytical techniques like X-ray diffraction, DSC and Fourier transform infrared spectroscopy were utilised to confirm the co-crystal formation. The dynamic solubility of etravirine in the co-crystal of ratio 1:1 and 1:2 was improved by approximately 2-3 fold as compared to pure etravirine This study helps in demonstrating the capability of co-crystalization method to enhance the solubility of etravirine.