Quantification of related/degraded impurities in Tolvaptan drug substance by HPLC

Abstract

A reverse phased high performance liquid chromatographic (HPLC) method was developed for the determination of Tolvaptan (TLP) drug substance and it process impurities TLPRC01, TLPRC02, TLPRC03, TLPRC04, TLPRC05 and TLPC06 using an analytical column Unison UK-C18, (250mm x4.6mm, 5µ) maintained at 30^oC ± 2^oC. The wavelength was set at 265 nm. Flow rate was maintained as 1.0 ml/min with injection volume of 10 µl. All the analytes could be separated with run time of 60 min. The peaks of analytes are well resolved with the resolution of 2.0. The results of all the validation parameters showed that the developed method is well confined to the limits of ICH guidelines. Degradation studies showed that the mass balance of Tolvaptan in all conditions is in the range of 98 to 102 %. The accuracy of six impurities TLPRC01, TLPRC02, TLPRC03, TLPRC04, TLPRC05 and TLPC06 found in the range of 80-120%. The proposed method is able to quantify the related compounds present in drug substance and also able to see the assay of drug substance in presence of degraded impurities without the loss of purity of drug substance and other impurities. The method has proved to be robust by introducing miniscule changes in the chromatographic conditions.