Hanan Merey

Citation:

Merey, H. A., "Simple spectrophotometric methods for the simultaneous determination of antipyrine and benzocaine", Bulletin of Faculty of Pharmacy, Cairo University, vol. 54, pp. 181-189, 2016.

Abstract:

Antipyrine and benzocaine are formulated together for the treatment of ear inflammation
and to relieve pain. Four spectrophotometric methods were developed for the simultaneous
determination of antipyrine (AN) and benzocaine (BE) in their combined dosage form. Method
A depends on applying dual wavelength method where antipyrine was determined by measuring
the absorbance at 254.1 and 309.1 nm (corresponding to zero difference of benzocaine), while the
absorbance difference at 230.1 and 263.5 nm (corresponding to zero difference of antipyrine) was
selected for benzocaine determination in the laboratory prepared spectrum. Method B depends
on measuring the peak amplitude of first derivative at 305 nm for calculating benzocaine concentration
then the total concentration of both drugs was determined using isoabsorptive point at
257.4 nm (antipyrine concentration was then calculated by subtraction). Method C is based on measuring
the peak difference of the ratio spectra at Dp (239.1–285 nm) and Dp (301.4–250 nm) for the
determination of antipyrine and benzocaine, respectively. Method D depends on measuring peak to
peak amplitude of the first derivative of ratio spectra at (234.5 + 244.2 nm) and peak amplitude at
295.5 nm for the determination of antipyrine and benzocaine, respectively. The proposed methods
were validated and applied for the analysis of antipyrine and benzocaine in their laboratory prepared
mixtures and pharmaceutical formulation. Statistical comparison between the results of
the proposed methods and those of the reported methods showed no significant difference.