SPECTROPHOTOMETRIC DETERMINATION OF SOME PHARMACEUTICAL COMPOUNDS USING 2,2-DIPHENYL-1-PICRYLHYDRAZYL

A spectrophotometric method for the determination of some pharmaceutic al amides, hydrazides and thiols is described. The method is based on the reaction of the studied drugs with 2,2-diphenyl-1-picryl hydrazyl (DPPH). The latter is employed to abstract a hydrogen atom from the dr ugs thereby promoting a process of radical coupling. This results in a reduction of the violet colour of DPPH with the formation of the yell ow coloured 2,2-diphenyl-1-picrylhydrazine (DPPH2). This fading in col our of DPPH reagent depends on the concentration of the drug being det ermined. Beer's law is obeyed in the ranges of 1-5 mug/ml (for isocarb oxazid and gliclazide), 0.25-2.5 mug/ml (for isoniazid), 0.5-5 mug/ml (for iproniazid), 1-7 mug/ml (for tolazamide), 2-15 mug/ml (for captop ril) and 1-6 mug/ml (for sulphathiourea). The validity of the method w as tested by analysing the studied drugs in pure form as well as in ta blets. Results of analyses were compared statistically with the offici al or reported methods.