Preparative resolution of praziquantel enantiomers by simulated counter-current chromatography

Abstract

The continuous chromatographic separation of a racemic anthelmintic drug, praziquantel, was carried out using a simulated counter-current system. The system consists of four identical columns (445 mm × 12.5 mm I.D.) connected in series through solenoid valves. The chiral stationary phase used is microcrystalline cellulose triacetate and the eluent is methanol. Feed at 50 mg/ml was continuously introduced into the system at 0.3 ml/min and 429 mg/h of (+)-praziquantel and 404 mg/h of (−)-praziquantel were obtained from the extract and raffinate streams, respectively. The optical purity of the products was more than 90%. This method provides an extremely useful technique for preparative-scale enantioseparation. Compared with conventional batch preparative-scale processes, this system offers a higher solute to adsorbent mass ratio.