Astemizole Tablets

» Astemizole Tablets contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of astemizole (C28H31FN4O).

Packaging and storage— Preserve in tight containers.

—

USP Astemizole RS

Identification— Transfer an amount of finely ground Tablets, equivalent to 100 mg of Astemizole, to a 100-mL volumetric flask, add methanol to volume, mix, and filter. Prepare a Standard solution of USP Astemizole RS in methanol having a concentration of 1 mg per mL. Separately apply 10 µL of each solution to a thin-layer chromatographic plate (see Chromatography

621

) coated with a 0.25-mm layer of chromatographic silica gel mixture. Develop the chromatogram in a solvent system consisting of a mixture of toluene, dioxane, methanol, and ammonium hydroxide (60:30:10:1) 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, air-dry, and examine under short-wavelength UV light: the RF value of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.

Dissolution

711

—

Medium: simulated gastric fluid TS (without the enzyme); 800 mL.

Apparatus 2: 100 rpm.

Time: 45 minutes.

Procedure— Determine the amount of astemizole (C28H31FN4O) dissolved from UV absorbances at the wavelength of maximum absorbance at about 285 nm of filtered portions of the solution under test, suitably diluted with Medium, in comparison with a Standard solution having a known concentration of USP Astemizole RS in the same Medium.

Tolerances— Not less than 80% (Q) of the labeled amount of astemizole (C28H31FN4O) is dissolved in 45 minutes.

Uniformity of dosage units

905

: meet the requirements.

Chromatographic purity—

Mobile phase, Standard preparation, and Chromatographic system— Proceed as directed in the Assay under Astemizole.

Test solution— Use the Assay preparation.

Procedure— Inject a volume (about 10 µL) of the Test solution into the chromatograph, record the chromatogram, and measure the peak responses. Calculate the percentage of each impurity in the portion of Tablets taken by the formula:

100(ri / rs)

in which ri is the peak response for each impurity; and rs is the sum of the responses of all of the peaks: not more than 0.25% of any individual impurity is found; and the sum of all impurities is not more than 1.0%.

Assay—

Mobile phase, Standard preparation, and Chromatographic system— Proceed as directed in the Assay under Astemizole.

Assay preparation— Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed quantity of the powder, equivalent to about 50 mg of astemizole, to a 50-mL volumetric flask. Add 25 mL of Mobile phase, mix for 30 minutes, dilute with Mobile phase to volume, and centrifuge. Use the supernatant as the Assay preparation.

Procedure— Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of astemizole (C28H31FN4O) in the portion of Tablets taken by the formula:

50C(rU / rS)

in which C is the concentration, in mg per mL, of USP Astemizole RS in the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.

Auxiliary Information— Please check for your question in the FAQs before contacting USP.

Topic/Question	Contact	Expert Committee
Monograph	Domenick Vicchio, Ph.D. Senior Scientific Liaison 1-301-998-6828	(SM42010) Monographs - Small Molecules 4
Reference Standards	RS Technical Services 1-301-816-8129 rstech@usp.org
711	Margareth R.C. Marques, Ph.D. Senior Scientific Liaison 1-301-816-8106	(GCDF2010) General Chapters - Dosage Forms

USP35–NF30 Page 2259

Pharmacopeial Forum: Volume No. 28(3) Page 745