METHOD FOR COULOMETRIC DETERMINATION OF WATER CONTENT IN DOSAGE FORM OF OINTMENT Russian patent published in 2017 - IPC G01N33/15 

FIELD: chemistry.

SUBSTANCE: invention relates to analytical chemistry and a method of determining water content in dosage form of ointment. Method comprises dissolution of a weight portion a dosage form of ointment in toluene: methanol solvent in ratio of 7:3, performing iodine electrical generation at constant current 50 mA in background electrolyte "Aqua M^®-Kulon AG" in an anode chamber, "Aqua M^®-Kulon CG" in a cathode chamber on a platinum electrode, further, introducing into a cell an aliquot of a solution of erythromycin eye ointment weighing 3 g, measuring time of reaching titration end point, calculating water content in aliquot by formula X = I×t×M/F, where I is current, 0.05 A; t is time for achieving titration end point, s; M is molar mass equivalent of water, 9.008 g/mol; F is Faraday constant, 96,485 C/mol, concurrently determining water in solvent and based on known formulae calculating water content in ointment.

EFFECT: use of method enables with high-accuracy to determine water content in dosage form of ointment.

1 cl, 2 tbl, 1 ex