Gradient high performance liquid chromatography method for determination of related substances in brexpiprazole api

The purpose of this research study is to develop a novel, simple, precise, accurate and economical method for determination of related substances in Brexpiprazole API. The chromatographic method for determination of related substances was developed on Kromasil C8, (250 mm x 4.6 mm, 5 µm) Column with tertiary gradient program. The mobiles phase used for separation was (a) Dipotassium hydrogen phosphate buffer with pH 5.5 ±0.05, (b) Mix of 9 volumes of acetonitrile and 1 volume of Tetrahydrofuran and (c) Methanol. At 254nm wavelength all releted substances were detected and responses of all related substances with limit level is very good. The detection of all related substances is about 0.33ppm and quantification is 1.5ppm.This developed method was validated as per ICH guideline and found out to be linear, accurate, specific, selective, precise, and robust. Test solution was found to be stable for 24 hrs. The method can be successfully applied for the determination of related substances in Brexpiprazole API.