(plye'' ka mye' sin).
» Plicamycin has a potency of not less than 900 µg of C52H76O24 per mg, calculated on the dried basis.
Packaging and storage Preserve in tight, light-resistant containers, at a temperature between 2 and 8.
USP Reference standards 11
B: The chromatogram obtained from the Assay preparation in the Assay exhibits a major peak for plicamycin the retention time of which corresponds to that exhibited by the Standard preparation, and the chromatogram compares qualitatively to that obtained from the Standard preparation.
Crystallinity 695: meets the requirements.
pH 791: between 4.5 and 5.5, in a solution containing 0.5 mg per mL.
Loss on drying 731 Dry about 100 mg, accurately weighed, in vacuum at a pressure not exceeding 5 mm of mercury at 25 for 4 hours: it loses not more than 8.0% of its weight.
Assay [notePrepare solutions of plicamycin in low-actinic glassware. ]
Mobile phase Prepare a suitable filtered and degassed mixture of 650 mL of 0.01 M phosphoric acid and 350 mL of acetonitrile.
Standard preparations Dissolve an accurately weighed quantity of USP Plicamycin RS in Mobile phase to obtain a solution having a concentration of 500 µg of plicamycin per mL. Dilute this solution with Mobile phase to obtain solutions containing 50, 100, and 150 µg of plicamycin per mL.
Assay preparation Transfer about 5 mg of Plicamycin, accurately weighed, to a 50-mL volumetric flask. Dissolve in Mobile phase, dilute with Mobile phase to volume, and mix.
Chromatographic system (see Chromatography 621)The liquid chromatograph is equipped with a 278-nm detector and a 4.6-mm × 25-cm column that contains packing L1. The flow rate is about 1.3 mL per minute. Chromatograph replicate injections of the Standard preparation, and record the peak responses as directed for Procedure: the relative standard deviation is not more than 2.0%.
Procedure Separately inject equal volumes (about 10 µL) of the Standard preparations and the Assay preparation into the chromatograph by means of a suitable microsyringe or sampling valve, record the chromatograms, and measure the responses for the major peaks. The retention time is about 13 minutes for plicamycin. Plot the peak responses of the Standard preparations versus concentration, in µg per mL, of plicamycin, and draw the straight line best fitting the three plotted points. From the graph so obtained, determine the concentration, in µg per mL, of plicamycin in the Assay preparation. Calculate the potency, in µg of C52H76O24 per mg, taken by the formula:
(50C / W)in which C is the concentration, in µg per mL, of plicamycin in the Assay preparation, and W is the weight, in mg, of Plicamycin taken.
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USP35NF30 Page 4343