METHOD FOR QUANTITATIVELY DETERMINING LEVOMYCETIN IN FOODS AND PHARMACEUTICAL PREPARATIONS Russian patent published in 2002 - IPC

FIELD: analytical methods in biochemistry. SUBSTANCE: invention provides method that can be applied in determining antibiotic in biological systems (blood, urine, etc.) when performing pharmacokinetic investigations, in toxicological and technical analyzes of drugs, animal feeds, and also can be a basis to create an antibiotic metabolism diagnostic system. Method consists in that levomycetin is first transferred from a sample into solution, after which one performs acid hydrolysis, precipitates protein from hydrolyzate, and determines levomycetin voltammetrically in protein- free hydrolyzate via registration of cathodic peaks of antibiotic on indicator mercury-film or glass-carbon electrodes in differential voltammogram record mode at potentials -(0.67+/-0.05) V and -(0.60+/-0.03) V respectively relative to saturated silver chloride electrode against 0.1 M C₆H₁₄O₇N₂(pH4,7÷5,1) (pH 4.7-5.1) or 0.1 M (NH₄)₂SO₄ to which HCl is added to give pH 5.1, scan velocity of potential being 10 to 25 mV/s. Concentration of levomycetin is determined from peak height utilizing certified mixture addition approach. EFFECT: increased analytical sensitivity, rapidity, and selectivity. 2 tbl, 4 ex