(da kar' ba zeen).
» Dacarbazine contains not less than 97.0 percent and not more than 102.0 percent of C6H10N6O.
[CautionGreat care should be taken in handling Dacarbazine, as it is a potent cytotoxic agent. ]
Packaging and storage Preserve in tight, light-resistant containers, in a refrigerator.
USP Reference standards 11
Identification The IR absorption spectrum of a potassium bromide dispersion of it exhibits maxima only at the same wavelengths as that of a similar preparation of USP Dacarbazine RS.
Residue on ignition 281: not more than 0.1%.
Related compounds Dissolve an accurately weighed quantity of Dacarbazine in 0.1 N hydrochloric acid to obtain a solution having a concentration of 40 mg per mL, and apply 5 µL of the solution to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Apply, separately, 5 µL of a methanolic solution containing 0.40 mg of USP Dacarbazine Related Compound A RS per mL, and 5 µL of an aqueous solution containing 0.40 mg of USP Dacarbazine Related Compound B RS per mL. Develop the chromatogram in a mixture of butanol, water, and acetic acid (5:2:1), until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow the solvent to evaporate. Locate the spots on the plate by viewing under short-wavelength UV light: any spots obtained from the test solution are not greater in size or intensity than the spots, occurring at the respective RF values, produced by the Standard solutions, corresponding to not more than 1.0% of dacarbazine related compound A and not more than 1.0% of dacarbazine related compound B.
Assay [noteThroughout this procedure, avoid exposing Dacarbazine and its solutions to light. ]
Standard preparations Transfer about 30 mg of USP Dacarbazine RS, accurately weighed, to a 50-mL volumetric flask, add 0.1 N hydrochloric acid to volume, and mix (Standard stock solution). Dilute a portion of Standard stock solution quantitatively and stepwise with 0.1 N hydrochloric acid to obtain an Acidic standard preparation having a known concentration of about 6 µg per mL. Dilute a portion of Standard stock solution quantitatively and stepwise with pH 7.0 phosphate buffer (see Buffer Solutions in the section Reagents, Indicators, and Solutions) to obtain a Neutral standard preparation having a known concentration of about 6 µg per mL.
Assay preparations Prepare as directed under Standard preparations, except to use about 30 mg of Dacarbazine, accurately weighed.
Procedure Concomitantly determine the absorbances of the Acidic standard preparation and the Acidic assay preparation in 1-cm cells at the wavelength of maximum absorbance at about 323 nm, with a suitable spectrophotometer, using 0.1 N hydrochloric acid as the blank. Concomitantly determine the absorbances of the Neutral standard preparation and the Neutral assay preparation in 1-cm cells at the wavelength of maximum absorbance at about 329 nm, using pH 7.0 phosphate buffer (see Buffer Solutions in the section Reagents, Indicators, and Solutions) as the blank. Calculate the quantity, in mg, of C6H10N6O in the portion of Dacarbazine taken by the formula:
5C[(A323 + A329)U / (A323 + A329)S]in which C is the concentration, in µg per mL, of USP Dacarbazine RS in the Standard preparations, and the parenthetic expressions are the sums of the absorbances of the Assay preparations (U) and the Standard preparations (S), respectively, measured at the wavelengths indicated by the subscripts.
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USP35NF30 Page 2802