Mi. Toral et al., DETERMINATION OF MEFENAMIC-ACID AND PARACETAMOL BY FIRST DERIVATIVE SPECTROPHOTOMETRY, Analytical letters, 29(15), 1996, pp. 2679-2689
A direct and simple first derivative spectrophotometric method has bee
n developed for the determination of mefenamic acid and paracetamol in
pharmaceutical formulations. A methanolic hydrochloric acid solution
was used as solvent for extracting the drugs from the formulations and
subsequently the samples were evaluated directly by derivative spectr
ophotometry. Simultaneous determination of both drugs can be carried o
ut using the zero-crossing and the graphical methods. The methods do n
ot require simultaneous equations to be solved. The calibration graphs
were linear in the ranges from 1.8x 10(-6) to 1.6 x 10(-4) M of mefen
amic acid and from 4.1 x 10(-6) to 1.4 x 10(-4) M of paracetamol. The
ingredients commonly found in commercial pharmaceutical formulations d
o not interfere. The proposed method was applied to the determination
of these drugs in tablets.