Dissolution á711ñ—
Medium:
sodium lauryl sulfate solution (5in 100);1000mL.
Apparatus 2:
100rpm.
Time:
180minutes.
Determine the amount of C12H15ClO3dissolved by employing the following method.
Mobile phase—
Prepare a degassed and filtered mixture of methanol and water (80:20).
Standard solution—
Transfer about 20mg of
USP Clofibrate RS,accurately weighed,to a 50-mLvolumetric flask.Add 20mLof methanol,mix to dissolve the clofibrate,dilute with water to volume,and mix.Dilute an aliquot quantitatively with methanol to obtain a final solution having a known concentration of about 80µg per mL.
Test solution—
Dilute a 5.0-mLportion of the solution under test to 25.0mL,using methanol.Allow to stand for 5minutes,and filter.
Chromatographic system—
The liquid chromatograph is equipped with a 226-nm detector and a 4-mm ×30-cm column that contains packing L1.The flow rate is about 1mLper minute.Chromatograph the Standard solution,and record the peak responses as directed for Procedure:the tailing factor is not more than 1.5;and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal portions (about 20µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the amount of C12H15ClO3dissolved.
Tolerances—
Not less than 80%(Q)of the labeled amount of C12H15ClO3is dissolved in 180minutes.
Assay—
Proceed with Capsules as directed in the
Assayunder
Clofibrate,using the following as the
Assay preparation:Weigh accurately not less than 20Capsules in a tared weighing bottle.With a sharp blade,carefully open the Capsules,without loss of shell material,and transfer the contents to a 100-mLbeaker.Remove any liquid from the emptied capsules by washing with several small portions of ether.Discard the washings,and allow the capsules to dry in a jet of dry air until the odor of ether no longer is perceptible.Weigh the empty capsules in the tared weighing bottle,and calculate the average net weight per capsule.Transfer an accurately weighed amount of capsule contents,equivalent to about 200mg of clofibrate,to a 100-mLvolumetric flask,add methanol to volume,and mix.Transfer 10.0mLof this solution to the
Ion-exchange column,and collect the eluate in a 100-mLvolumetric flask.Rinse the column with 25mLof methanol,collect the rinsings in the volumetric flask,dilute with methanol to volume,and mix.Transfer 5.0mLof this solution to a 50-mLvolumetric flask,dilute with methanol to volume,and mix.Calculate the quantity,in mg,of C
12H
15ClO
3in the portion of Capsules taken by the formula:
10C(AU/AS),
in which
Cis the concentration,in µg per mL,of
USP Clofibrate RSin the
Standard preparation,and
AUand
ASare the absorbances of the
Assay preparationand the
Standard preparation,respectively.