SIMULTANEOUS DETERMINATION OF ASCORBIC-ACID, PYRIDOXINE HYDROCHLORIDE, AND TYROSINE BY DERIVATIVE UV SPECTROPHOTOMETRY

A new UV spectrophotometric method for resolving a three-component dru g mixture of ascorbic acid (I), pyridoxine hydrochloride (II), and tyr osine (III), on the basis of the first-derivative UV spectra and zero- crossing technique, is described. Beer's law was obeyed in the concent ration range of 7.0-15.0, 0.25-1.0 and 8.0-40.0 mu g/ml for I, II, and III, respectively. Lower limits of detection at the 95% confidence le vel were 2.88, 0.69, and 5.43 mu g/ml, respectively. The advantages of the proposed method (speed, easy sample preparation, and lower cost p er analysis) also include its application to the content uniformity an d dissolution test of a three-component mixture of drugs.