Preparation, Pharmaceutical Properties and Stability of Lesinurad Co-crystals and Solvate

Abstract

Lesinurad is a BCS class 2, low solubility drug, indicated for hyperglycemia associated with gout in patients who have not achieved target serum uric acid levels with a xanthine oxidase inhibitor alone. Co-crystallization and solvate formation with pharmaceutically acceptable coformers and solvents are one of the best ways to improve solubility of BCS class 2 drugs. Lesinurad DMSO (dimethyl sulphoxide) solvate (1:1 mole ratio), urea and 4-Hydroxy benzoic acid co-crystals (1:1 mole ratio) prepared and scaled up to 100g and characterized using PXRD, FTIR, DSC, TGA, solid state 13C NMR and H1 NMR. Unique PXRD pattern, red shift in acid carbonyl stretching of Lesinurad in DMSO solvent, Urea co-crystal and parahydroxybenzoic acid co-crystals are the evidence of solvate and co-crystal formation. Urea co-crystal is further characterized using 13C solid state NMR. Deshielding of acid carbonyl carbon from δppm of 168.98 to 173.12 and shielding of urea carbonyl carbon from δppm of 169 to 164.56 indicates co-crystal formation between lesinurad and urea. DMSO solvate has shown 1.26 fold increase in Intrinsic dissolution rate measurement (IDR) over marketed Form-II and urea co-crystal. DMSO solvate, urea and 4-Hydroxy benzoic acid cocrystals of lesinurad are stable for six months at 40 °C and 75%RH.