Aim: A spectrophotometric UV-VIS fast, sensitive and simple method was developed for quantitative determination of two new antimicrobial preservatives (oxi-acetyl-mandelic acid and oxi-propionyl mandelic acid) and validated according to validation quides.
Material and methods: The absorption spectra were recorded at 200-400 nm, and the absorbances were measured at 256 nm for oxi-acetyl mandelic acid and 258 nm for oxipropionyl mandelic acid. Optimum working conditions were established and the method was validated. The developed and validated method was applied to determine these two preservatives from ointments, in which the preservatives were incorporated.
Results: The method has a good linearity in the concentration range 0.1-1.5 mg/ml (for oxi-acetyl mandelic acid) and 0.1-1 mg/ml (for oxi-propionyl mandelic acid). The RSD for the precision of the method was 0.96328 for oxiacetyl mandelic acid and 0.797612 for oxi-propionyl mandelic acid. The relative standard deviation was 0.726367% for oxi-acetyl mandelic acid and 0.726234% for oxipropionyl mandelic acid. In the ointment samples, the concentration of oxi-acetyl mandelic acid and oxi-propionyl mandelic acid were within the limits specified by pharmacopoeia for ointments.
Conclusions: The developed and validated spectrophotometric method, for the determination of oxi-acetyl mandelic acid and oxi-propionyl mandelic acid is simple, easy to perform, fast and cost effective.