LC-MS Studies on Related Substances in Cilastatin Sodium
Yang Ming · Chinese Journal of Pharmaceuticals · 2012
A new LC-MS method was established for the determination of the related substances in cilastatin sodium.The specialization of the method and the degradation pathway of the related substances were also studied.A Sepax HP C18 column was used with the mobile phase of acetonitrile-0.1% formic acid aqueous solution(30︰70,A) and 0.1% formic acid aqueous solution(B) by gradient elution,which was operated at 15%-100% A(0-30 min) followed by 100% A(30-45 min).The data was acquired in positive ion mode.Ten related substances were detected in cilastatin sodium,including three compounds(impurity A,B and C) collected by European Pharmacopoeia,the isomer of impurity A,the acid hydrolysate of cilastatin,four isomeric compounds of cilastatin and a dipolymer.