SPECTROPHOTOMETRIC MULTICOMPONENT ANALYSIS OF A MIXTURE OF CHLORHEXIDINE HYDROCHLORIDE AND LIDOCAINE HYDROCHLORIDE IN PHARMACEUTICAL FORMULATION USING DERIVATIVE SPECTROPHOTOMETRY AND PARTIAL LEAST-SQUARES MULTWARIATE CALIBRATION

摘要

Two spectrophotometric methods were applied to the simultaneous assay of chlorhexidine hydrochloride (CHL) and lidocaine hydrochloride (LIH) in pharmaceutical formulations. Using derivative spectropho-tometry, CHL was determined by measurement of itsfirst derivative signal at 290 nm (peak to zero amplitude) in the concentration range 5-9 mu g/mL, and LIH was analysed by measurement of its second derivative signals at 272 and 276 nm (peak to peak amplitude) in the concentration range 160-480 mu g/mL.With the partial least-squares (PLS-2), the experimental calibration matrix was constructed using 9 samples. The concentration ranges considered were 5, 6, 7 mu g/mL for CHL and 220, 240, 260 mu g/mL for LIH. The absorbances were recorded between 240 and 310 nm at every 5 nm.