Spectrophotometric Determination of Metoclopramide and Oxybuprocaine Through Ion Pair Formation with Thiocyanate and Molybdenum(V) or Cobalt(II)

Abstract

Two spectrophotometric methods involve the formation of two different ion pairs between the drug and inorganic complexes, Mo(V) and Co(II) thiocyanates followed by their extraction with dichlor⊘methane and o-nitrotoluene, respectively. The optimum conditions for the ion pair formation are established. The methods permit the determination of metoclopramide and oxybuprocaine hydrochlorides over a concentration range of 1-20 μg ml⁻¹ and 20–240 μg ml⁻¹ using Mo(V) and Co(II) thiocyanates, 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 thiocyanate concentration. Results of the analysis of drug substances and their dosage forms by the proposed methods are in good agreement with those obtained by the official methods.