SIMULTANEOUS ANALYSIS OF PYRIDOXINE AND MELATONIN IN TABLET FORMULATION BY DERIVATIVE ULTRAVIOLET SPECTROSCOPY

A method for simultaneous analysis of pyridoxine and melatonin by seco nd and third derivative UV - spectroscopy, the ''zero - crossing'' tec hnique, is described. The determination has been carried out in 0.1 mo l dm(-3) hydrochloric acid solution and the concentration range of 2 - 10 mu g/ml pyridoxine and 0.5 - 3.5 mu g/ml melatonin. Lower limits o f detection at the 95% confidence level were 0.26 mu g/ml for pyridoxi ne and 0.05 mu g/ml for melatonin The advantages of the proposed metho d include its application for the assay and in-vitro dissolution studi es of pyridoxine and melatonin from two different tablet formulations.