SPECTROPHOTOMETRIC DETERMINATION OF METOCLOPRAMIDE AND OXYBUPROCAINE THROUGH ION-PAIR FORMATION WITH THIOCYANATE AND MOLYBDENUM(V) OR COBALT(II)

Two spectrophotometric methods involve the formation of two different ion pairs between the drug and inorganic complexes, Mo(V) and Co(II) t hiocyanates followed by their extraction with dichloromethane and o-ni trotoluene, respectively. The optimum conditions for the ion pair form ation are established. The methods permit the determination of metoclo pramide and oxybuprocaine hydrochlorides over a concentration range of 1-20 mu g ml(-1) and 20-240 mu g ml(-1) using Mo(V) and Co(II) thiocy anates, respectively. Molar ratio of drug to Mo(V) or Co(II) indicates a 2:1 ratio for the two drugs studied in the presence of excess thioc yanate concentration. Results of the analysis of drug substances and t heir dosage forms by the proposed methods are in good agreement with t hose obtained by the official methods.