Title screen

4-O-Я-D-(glucopyranosyloxy)-benzoic acid sodium salt (4-GBA) is promising potassium-sparing diuretic and anti-inflammatory drug. For the survey of 4-GBA as pharmaceutical substance, a durable method of its quantification is needed. In the present study, a titrimetric method for 4-GBA quantification since it is evident, very simple, fast, applicable for routine analysis and there is no need of using reference standards was developed. Aqueous titration gave unsatisfactory result. Thus, based on the weak basic properties of the 4-GBA, non-aqueous titration was chosen. Glacial acetic acid was used as a solvent, and an anhydrous solution of perchloric acid in glacial acetic acid was used as a titrant. End-point detection was carried out potentiometrically (method A) and visually with violet crystalline as an indicator (method B). Using aqueous titration, we determined pKa of 4-GBA as 4.27. The developed non-aqueous titration method is of excellent linearity (r2 = 0.9995 and r2 = 0.9947 for method A and method B, respectively), accuracy (recovery from 98.8 to 101.1 % and from 98.1 to 103.2 % for method A and method B, respectively) and precision (RSD = 2% for intra- and inter-day analysis). The developed method is fast, simple, cheap and is applicable for the quantitative determination of 4-GBA both in pure form, bulk and pharmaceutical formulations.