Simultaneous determination of two-component mixtures in pharmaceutical formulations containing chlordiazepoxide by ratio spectra derivative spectrophotometry

The ratio spectra derivative spectrophotometry was applied for the simultan eous determination of chlordiazepoxide( CH) with clidinium bromide(CL), pip enzolate bromide(PI) or amitriptyline hydrochloride (A) in binary mixtures. The analytical signals were measured at 243.1 and 214.8 nm in the CH - CL mixture, 271.4 and 256.7 nm in the CH - PI mixture, and 264.9 and 218.0 nm in the CH - A mixture for CH and its co - existing compounds, respectively, in the first derivative mode in methanol, Calibration graphs were establis hed for 2.0 - 38.0 mu gml(-1) CH and 4.0- 20.0 mu gml(-1) CL in CH - CL mix ture, for 2.0 - 38.0 mu gml(-1) CH and 4.0-36.0 mu gml(-1) PI in CH - PI mi xture, and for 2.0-28.0 mu gml(-1) CH and 4.0-36.0 mu gml(-1) A in CH - A m ixture. The method was successfully applied to the pharmaceutical formulati ons containing the above-mentioned drug combinations without any interferen ce by the excipients. Vierordt's method was also developed for a comparison method.