SIMULTANEOUS DETERMINATION OF DIAZEPAM AND PYRIDOXINE IN SYNTHETIC MIXTURES AND PHARMACEUTICAL FORMULATIONS USING GRAPHICAL AND MULTIVARIATE CALIBRATION-PREDICTION METHODS

Several methods are reported for the simultaneous determination of dia zepam and pyridoxine: two graphical methods (zero-crossing and derivat ive quotient spectra); and two numerical methods (multiple linear regr ession and partial least-squares regression). The methods have been ap plied in the concentration ranges 1.4-4.0 mu g ml(-1) diazepam and 4.0 -12.0 mu g ml(-1) pyridoxine. The accuracy and precision of the method s have been determined and they have been validated by analysing synth etic mixtures containing the two drugs in variable proportions. The me thods were also applied to the determination of diazepam and pyridoxin e in pharmaceutical preparations. The analytical results were quite go od in all cases.