Test solution: 10 mg per mL, in dioxane.

(Official January 1, 2007)

Mobile phase— Prepare a suitable degassed solution of 3 volumes of acetonitrile in 2 volumes of water, such that the retention time of beclomethasone dipropionate is approximately 6 minutes and that of testosterone propionate is approximately 10 minutes.

Internal standard solution— Dissolve a suitable quantity of USP Testosterone Propionate RS, accurately weighed, in methanol to obtain a solution having a concentration of about 1.2 mg per mL.

Standard preparation— Dissolve a suitable quantity of USP Beclomethasone Dipropionate RS, accurately weighed, in methanol to obtain a solution having a concentration of about 1.4 mg per mL. Transfer 4.0 mL of this solution to a suitable vial, and add 4.0 mL of Internal standard solution to obtain a solution having a known concentration of about 0.7 mg per mL with respect to the Reference Standard and 0.6 mg per mL with respect to the internal standard.

Assay preparation— Weigh accurately about 70 mg of Beclomethasone Dipropionate, transfer to a 50-mL volumetric flask, dilute with methanol to volume, and mix. Transfer 4.0 mL of this solution to a suitable vial, and add 4.0 mL of Internal standard solution.

Procedure— Separately inject equal volumes (between 5 µL and 25 µL) of the Assay preparation and the Standard preparation into a high-performance liquid chromatograph (see Chromatography 621) operated at room temperature, adjusting the specimen size and other operating parameters such that the peak obtained with the internal standard in the Standard preparation is about 0.6 to 0.9 full-scale. Typically, the apparatus is fitted with a 4-mm × 30-cm column that contains packing L1 and is equipped with an UV detector capable of monitoring absorption at 254 nm, a suitable recorder, and a pump capable of operating at a column pressure of up to 3500 psi. In a suitable chromatogram, the coefficient of variation for five replicate injections of the Standard preparation is not more than 3.0%. Calculate the quantity, in mg, of C28H37ClO7 in the portion of Beclomethasone Dipropionate taken by the formula: in which C is the concentration, in mg per mL, of USP Beclomethasone Dipropionate RS in the Standard preparation; and RU and RS are the peak height ratios of beclomethasone dipropionate to the internal standard obtained from the Assay preparation and the Standard preparation, respectively.