Gradient liquid chromatographic method for determination of chlorhexidine and its degradation products in bulk material.

A liquid chromatographic method was developed for determination of chlorhexidine and its degradation products in unformulated drug substance. A nonlinear gradient from 80% 0.1M ammonium acetate buffer, pH 5.0, to 20% buffer over 90 min (balance is acetonitrile) is applied to a 3 microns octadecylsilane bonded-phase column. The drug and some of its degradation products are determined at 230 nm. Of 11 previously identified degradation products, 9 are determined with good precision (relative standard deviation of peak area is < 2%).