Spectrophotometric determination of oxytetracycline in pharmaceutical preparations using sodium molybdate as analytical reagent.
A spectrophotometric method is proposed for the determination of oxytetracycline in pharmaceutical preparations. The method is based on the measurement of the absorbance of the molybdate-oxytetracycline complex at 404 nm (pH 5.50; mu = 0.1 M; 20 degrees C). The composition of the complex (1:1) was determined by the application of the spectrophotometric methods of Job and Bent-French (pH 5.50; lambda = 390 nm; mu = 0.1 M). The relative stability constant (K' = 10(4.6) of the complex was obtained by the methods of Sommer and Nash (pH 5.50; lambda = 390 nm; mu = 0.1 M; 20 degrees C). The molar absorptivity of the complex was 9.5 x 10(3) l mol-1 cm-1. Beer's law was obeyed over the concentration range 2.48-34.78 micrograms ml-1. The relative standard deviation RSD (n = 10) was 0.27-0.39%. The method proposed can be applied to the assay of oxytetracycline in capsules. The detection limit of oxytetracycline is 2.5 micrograms ml-1.
Jelikić-Stankov
M
M
Institute of Analytical Chemistry, Faculty of Pharmacy, Belgrade, Yugoslavia.
Veselinović
D
D
Malesev
D
D
Radović
Z
Z
D002214:Capsules; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D008982:Molybdenum / Q000737:chemistry; D010118:Oxytetracycline / Q000032:analysis* / Q000737:chemistry; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet
D002214:Capsules; D007202:Indicators and Reagents; D012996:Solutions; D008982:Molybdenum; C024687:sodium molybdate(VI); D010118:Oxytetracycline