THE ASSESSMENT OF THE METHOD FOR QUANTITATIVE DETERMINATION OF PREDNISOLONE IN THE OINTMENT BY THE REACTION WITH PHENYLHYDRAZINE
Adaptation and validation of the analytical method of photocolorimetric determination of prednisolone using the reaction with phenylhydrazine by the standard method have been carried out in the scientific research laboratory according to standard procedures as described in the State Pharmacopoeia of Ukraine. The main validation characteristics have been identified using the model solution with the standard substance. It has been found that the criteria of linearity and precision are observed in the range of concentrations of 80-120% (0.08-0.12 mg/ml in the test solution or 0.4-0.6% of prednisolone in the ointment), and they are statistically and practically insignificant (a < S <sub>a</sub> * 1.86 = 4.7, Aas% < 3.20 = 2.86, 5 < 1.0240 = 0.92). The correct results obtained have allowed to test the method for determining prednisolone in the model extraction from “0.5% Prednisolone” ointment in the range of 80-120% of the nominal concentration. The study of robustness of the method performed has allowed to determine that it is necessary to follow a strict temperature range during the reaction to produce correct results (60°C±1°). The amount of phenylhydrazine in the reagent may vary between 0.4-1.0 g/l. Criteria of linearity, precision and convergence for the model extraction of the ointment are also observed within the whole range of determination and are statistically and practically insignificant (a < S <sub>a</sub> * 1.86 = 4.4, Aas% < 3.20 = 2.71, 5 < 1.0240 = 1.00). The method is acceptable for use in laboratories of the drug quality control and could be applied for determination of prednisolone in “0.5% Prednisolone” ointment with the hydrophobic base within the range of concentrations of 0.4-0.6%.