Identification—
Using a volume of Injection, equivalent to about 50 mg of biperiden lactate, and using a solution of 50 mg of
USP Biperiden RS in 25 mL of 0.01 N hydrochloric acid, proceed as directed under
Identification—Organic Nitrogenous Bases 
181
, beginning with “Transfer the liquid to a separator”: the Injection meets the requirements of the test.
Assay—
Phosphate buffer–bromocresol purple solution—
Prepare as directed in the Assay under Biperiden Hydrochloride Tablets.
Standard preparation—
Transfer about 80 mg of
USP Biperiden RS, accurately weighed, to a 100-mL volumetric flask, add methanol to volume, and mix. Transfer 5.0 mL of this solution to a second 100-mL volumetric flask, add 25 mL of water, dilute with methanol to volume, and mix to obtain a
Standard preparation having a known concentration of about 40 µg per mL.
Assay preparation—
Transfer an accurately measured volume of Injection, equivalent to about 5 mg of biperiden lactate, to a 100-mL volumetric flask, add 25 mL of water, dilute with methanol to volume, and mix.
Procedure—
Proceed as directed in the
Assay under
Biperiden Hydrochloride Tablets. Calculate the quantity, in mg, of C
21H
29NO·C
3H
6O
3 in each mL of the Injection taken by the formula:
(401.55 / 311.47)(0.1C / V)(AU / AS),
in which 401.55 and 311.47 are the molecular weights of biperiden lactate and biperiden, respectively;
C is the concentration, in µg per mL, of
USP Biperiden RS in the
Standard preparation; V is the volume, in mL, of Injection taken; and
AU and
AS are the absorbances of the solutions from the
Assay preparation and the
Standard preparation, respectively.
-bicyclo[2.2.1]hept-5-en-2-yl-