Abstract
Separatory determination of oxytetracycline from oxytetracycline preparation containing ascorbic acid was carried out by the use of a Permutit column. A solution (5cc.) of oxytetracycline preparation containing ascorbic acid (10-200γ/cc.) was passed through a column of acid-treated Permutit to effect adsorption of oxytetracycline on Permutit, the column was washed with five 10-cc. portions of distilled water to remove ascorbic acid from the column completely, and the column was eluted with 20cc. of 0.2N sodium hydroxide solution to desorb oxytetracycline. The effluent was received in a vessel containing 4cc. each of N hydrochloric acid and N acetic acid, and the total volume was brought to 50cc. To 5cc. of this solution, 1cc. of p-nitrobenzenediazonium chloride reagent is added and the mixture is warmed at 70° for 25 minutes. This is cooled in running water and the optical density of this solution is measured at 440mμ to obtained the potency of oxytetracycline. The values obtained by this method with oxytetracycline preparation containing ascorbic acid, the sample solution of which had been allowed to stand for a long time, were compared with that obtained by biological method and a fairly well agreeing result was obtained. In this case, aqueous solution containing oxytetracycline alone was allowed to stand under the same conditions and it was found that the rate of decomposition was somewhat higher in the sample containing ascorbic acid.
