Dissolution 711
Medium:
pH 4.5 acetate buffer; 900 mL.
Apparatus 2:
50 rpm.
Time:
30 minutes.
Determine the amount of C29H32O13 dissolved by employing the following method.
Buffer solution
Dissolve 5.44 g of sodium acetate in 2000 mL of water, adjust with acetic acid to a pH of 4.0, and filter.
Mobile phase
Prepare a filtered and degassed mixture of
Buffer solution and acetonitrile (74:26). Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard solution
Dissolve, with sonication, an accurately weighed quantity of
USP Etoposide RS in a volume of methanol equivalent to 2% of the final solution volume. Dilute with
Dissolution Medium to obtain a solution having a known concentration of about 55 µg per mL, and mix.
Test solution
At 30 minutes withdraw a 10-mL aliquot from the dissolution vessel.
Chromatographic system
The liquid chromatograph is equipped with a 240-nm detector and a 3.9-mm × 30-cm column that contains packing L11. The flow rate is about 2 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
Separately inject equal volumes (about 50 µL) of the filtered portions of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Determine the amount of C29H32O13 dissolved.
Tolerances
Not less than 80% (Q) of the labeled amount of C29H32O13 is dissolved in 30 minutes.
Assay
Buffer solution, Mobile phase, Standard preparation, System suitability solution, and Chromatographic system
Proceed as directed in the Assay under Etoposide.
Assay preparation
Transfer an accurately counted number of Capsules, equivalent to about 500 mg of etoposide, to a 500-mL volumetric flask, add about 400 mL of Mobile phase, and stir using a magnetic bar for about 15 minutes, followed by sonication for about 1 hour with occasional shaking. Cool, dilute with Mobile phase to volume, stir for an additional 5 minutes, and filter. Transfer 10.0 mL of this solution to a 50-mL volumetric flask, dilute with Mobile phase to volume, and mix.
Procedure
Proceed as directed in the
Assay under
Etoposide. Calculate the quantity, in mg, of etoposide (C
29H
32O
13) per Capsule by the formula:
2500(C/N)(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Etoposide RS in the
Standard preparation; N is the number of Capsules taken; and
rU and
rS are the etoposide peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.