PH INDUCED DIFFERENCE SPECTROPHOTOMETRIC ASSAY OF PARACETAMOL AND MEFENAMIC ACID IN TABLETS

Cem YÜCESOY*°, Kezban TÜLEK*

*Ankara University, Faculty of Pharmacy, Departemant of Analytical Chemistry, 06100 Tandogan, Ankara, TURKEY.
°Corresponding Author

Summary:
Binary combinations of paracetamol (P) and mefenamic acid (M) were determined by pH induced difference spectrophotometry. For this purpose two sets of solutions of the compounds in 0.02 N methanolic NaOH and 0.02 N methanolic HCl were prepared.Acidic solutions were used as blank in the measurements. Difference absorbances of standard and sample solutions were read at 272.5 nm for P and 362.0 nm for M.The recoveries of P and M from standard mixtures were 98.3 % for P and 98.9 % for M, respectively. Assay results of the commercial formulation were in good agreement with the stated contents of the dosage units and with the results of Vierordt’s method. The reproducibility of the assay results as relative standard deviation is 0.79 % for P and 1.19 % for M, respectively.

Key words:
Paracetamol, Mefenamic acid, Simultaneous determination, pH Induced difference spectrophotometry.