Identification—
Solution:
25 µg per mL.
Medium:
methanol.
Absorptivity at 445 nm, calculated on the dried basis, is not less than 95.0% and not more than 103.0% of that of
USP Dactinomycin RS, the potency of the Reference Standard being taken into account.
Ratio:
A240/A445 between 1.30 and 1.50.
B:
The chromatogram obtained from the Assay preparation in the Assay exhibits a major peak for dactinomycin, 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.
Assay—
[NOTE—In this procedure, use a freshly prepared
Standard preparation and
Assay preparation, protected from light.
]
Mobile phase—
Prepare a suitable mixture of acetonitrile, 0.04 M sodium acetate, and 0.07 M acetic acid (approximately 46:25:25), filter through a membrane filter (1-µm or finer porosity), and degas. [NOTE—The acetonitrile concentration may be varied to provide appropriate Chromatographic system performance and to provide a suitable elution time.]
Standard preparation—
Dissolve an accurately weighed quantity of
USP Dactinomycin RS in
Mobile phase, and dilute quantitatively with
Mobile phase to obtain a solution having a known concentration of about 1200 µg of dactinomycin per mL.
Assay preparation—
Dissolve about 30 mg of Dactinomycin, accurately weighed, in Mobile phase to make 25.0 mL, and mix.
Chromatographic system
(see
Chromatography 
621
)—The liquid chromatograph is equipped with a 254-nm detector and a 3.9-mm × 30-cm column that contains packing L1. The flow rate is about 1.0 mL per minute. Chromatograph three replicate injections of the
Standard preparation, and record the peak responses as directed under
Procedure: the relative standard deviation is not more than 1.0%.
Procedure—
Separately inject equal volumes (about 20 µL) of the
Standard preparation and the
Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. The retention time is about 25 minutes for Dactinomycin. Calculate the potency, in µg, of C
62H
86N
12O
16 per mg taken by the formula:
25(C / W)(rU / rS),
in which
C is the concentration, in µg, of dactinomycin in each mL of the
Standard preparation; W is the weight, in mg, of Dactinomycin taken; and
rU and
rS are the peak responses of the
Assay preparation and the
Standard preparation, respectively.
;)
for 3 hours: it loses not more than 5.0% of its weight.
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