Two simple and sensitive extractive visible spectro photometric methods (A and B) for the assay of Methoxamine hydrochloride (MHC), in pure and pharmaceutical formulations, The method-A is based on the condensation reaction of MHC reduced with sodium 1,2-naphthaquinone-4-sulfonate (NQS) in an alkaline medium to form an orange-red colored Schiff's base of maximum absorption peak (λmax) at 445 nm,The method-B is based on the formation coloured complexes with the dimethoxy benzene nucleus of brucine is attacked by Per Iodate with the formation of o-quinone (bruciquinone) which in turn undergoes nucleophilic attack on the most electron rich position of the coupler i.e., proton bearing amino group (primary amine), to give 1-mono substituted bruciquinone derivative. The reaction mechanism in both methods were discussed. The absorbance of colored complex is gound at 520nm. Beer's law is obeyed in the concentration range 5-30 μg/Ml,50-500 μg/Ml, the molar absorptivity values are1.9652 x 105, 1.4797 x 104L/mol.cm, Sandell sensitivity are1.2605 x 10-3,1.6741x10-2ng/cm2 (For methods A&B).The methods proposed gave reproducible results with the percentage recoveries in the formulations found to be 99.800 to 99.772 (Method A) and 99.812 to 99.749 (Method B).
