Objective To establish and demonstrate the two-wavelength
ultraviolet spectrophotome-try (TWUS) on the
assay of
suramin in the
vitreous of rabbits. Methods 25 albino rabbits were sacri-ficed and enucleated eyeballs. After a series of procedures, including frozen, ground, added acetoni-trile, centrifuged and diluted, the vitreous were measured for theirs continuous photo spectrum at wave-length range from 350
nm to 190 nm, and the absorbance was measured just at
wavelength 261 nm and 269 nm. The verified items included individual difference of rabbits, specificity of the assay, stan-dard curve, precision ( relative standard deviation ), accuracy ( relative rate of recovery ) and sensitivi-ty ( the minimum detective concentration, ρmin ) of the assay, as well as the stability of the detected simple. Results When wavelength of 261 nm and 269 nm was chosen as a pair of equal point of ab-sorbance, all of the 6 rabbits had no difference in absorbance. There were similar photo spectrums a-mong the blank vitreous, drug -injected vitreous and drug-added vitreous. The wave crest of all spec-trum localized at 265nm or about showed no marked shift. The standard equation of the line was y = 4 234 x + 2 (r = 0.999 1 ). During one day, the relative standard deviation of 3 different concentra-tion were 13.16%, 9.67% and 10.35%, with theirs relative rate of recovery ( 95.89 ± 0.08 )%, ( 96.69 ± 0.07 )% and ( 97.43 ± 0.01 ) % respectively. The ρmin was 45 μg/mL. Although the samples could not be stored at room temperature over 8 h, those stored at 4 ℃ and -20 ℃ or less than 8 h at room temperature were very stable for measurement. Conclusion On given conditions, the individual difference of rabbits can be neglected. All the data of each verified item are in accor-dence with the national relevant rules. Therefore, two-wavelength
ultraviolet spectrophotometry is a reli-able method for measurement of drug mass concentration in vitreous.
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