A: Infrared Absorption 197K—

Test specimen— Grind 20 Tablets to a fine powder, add 50 mL of chloroform, stir for 3 to 5 minutes, and filter into a 250-mL evaporating flask. Evaporate the solution with the aid of a rotary evaporator to dryness at low heat. Use the residue.

B: The relative retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.

Medium: 0.01 N hydrochloric acid; 500 mL.

Apparatus 2: 50 rpm.

Time: 30 minutes.

Procedure— Determine the amount of C21H31N5O2.HCl dissolved by employing UV absorption at the wavelength of maximum absorbances at about 235 nm on filtered portions of the solution under test, suitably diluted with 0.01 N hydrochloric acid, in comparison with a Standard solution having a known concentration of USP Buspirone Hydrochloride RS in the same Medium.

Tolerances— Not less than 80% (Q) of the labeled amount of C21H31N5O2.HCl is dissolved in 30 minutes.

(Official January 1, 2007)

Buffer solution, Mobile phase, Internal standard solution, Standard stock solution, Standard preparation, and Chromatographic system— Proceed as directed in the Assay under Buspirone Hydrochloride.

Assay preparation— Transfer a number of Tablets, equivalent to about 100 mg of buspirone hydrochloride, to a 200-mL volumetric flask, add 50 mL of 1 N hydrochloric acid, and shake for 15 minutes. Add about 100 mL of water, and shake for 30 minutes. Dilute with water to volume, mix, and filter, discarding the first 20 mL of the filtrate. Pipet 10.0 mL of the filtrate and 10.0 mL of Internal standard solution into a 50-mL volumetric flask, dilute with water to volume, and mix.

Procedure— Proceed as directed for Procedure in the Assay under Buspirone Hydrochloride. Calculate the quantity, in mg, of buspirone hydrochloride (C21H31N5O2·HCl) in the Tablets taken by the formula: in which L is the labeled amount, in mg, of buspirone hydrochloride in each Tablet; D is the concentration, in mg per mL, of buspirone hydrochloride in the Assay preparation, based on the labeled quantity per Tablet and the extent of dilution; C is the concentration, in mg per mL, of USP Buspirone Hydrochloride RS in the Standard preparation; and RU and RS are the peak response ratios of buspirone hydrochloride to propylparaben obtained from the Assay preparation and the Standard preparation, respectively.