A: Triturate a portion of finely powdered Tablets, equivalent to about 10 mg of procyclidine hydrochloride, with 20 mL of chloroform, filter, evaporate the filtrate on a steam bath to dryness, and dry the residue at 105 for 1 hour: the IR absorption spectrum of a potassium bromide dispersion of the procyclidine hydrochloride so obtained exhibits maxima only at the same wavelengths as that of a similar preparation of USP Procyclidine Hydrochloride RS.

B: A portion of finely powdered Tablets, equivalent to about 50 mg of procyclidine hydrochloride, responds to Identification test B under Procyclidine Hydrochloride.

Medium: water; 900 mL.

Apparatus 2: 50 rpm.

Time: 45 minutes.

Procedure— Determine the amount of C19H29NO·HCl dissolved, employing the procedure set forth in the Assay, making any necessary modifications.

Tolerances— Not less than 75% (Q) of the labeled amount of C19H29NO·HCl is dissolved in 45 minutes.

(Official January 1, 2007)

Bromocresol purple solution— Dissolve 250 mg of bromocresol purple in dilute glacial acetic acid (1 in 50) to make 1000 mL.

Standard preparation— Transfer about 25 mg of USP Procyclidine Hydrochloride RS, accurately weighed, to a 100-mL volumetric flask, add water to volume, and mix. Transfer 10.0 mL of this solution to a second 100-mL volumetric flask, dilute with Bromocresol purple solution to volume, and mix. The concentration of the Standard preparation is about 25 µg per mL.

Assay preparation— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 2.5 mg of procyclidine hydrochloride, to a 100-mL volumetric flask, add 10.0 mL of water, and mix. Dilute with Bromocresol purple solution to volume, mix, and allow the undissolved particles to settle. Use the supernatant as directed in the Procedure.

Procedure— Transfer 5.0 mL each of the Standard preparation and the Assay preparation to individual 60-mL separators. Transfer 0.5 mL of water and 4.5 mL of Bromocresol purple solution to a third separator to provide the blank. Extract each solution with 20.0 mL of chloroform, and filter each extract, discarding the first 5 mL of the filtrate. Concomitantly determine the absorbance of each subsequent filtrate in a 1-cm cell at the wavelength of maximum absorbance at about 405 nm, with a suitable spectrophotometer, against the blank. Calculate the quantity, in mg, of C19H29NO·HCl in the portion of Tablets taken by the formula: in which C is the concentration, in µg per mL, of USP Procyclidine Hydrochloride RS in the Standard preparation, and AU and AS are the absorbances of the solutions from the Assay preparation and the Standard preparation, respectively.