Packaging and storage—
Preserve in well-closed, light-resistant containers.
Identification—
B:
Digest a quantity of powdered Tablets, equivalent to about 25 mg of chlorpromazine hydrochloride, with 25 mL of water, and filter: the solution so obtained responds to
Identification test
C under
Chlorpromazine Hydrochloride.
Dissolution 
711
—
Medium:
0.1 N hydrochloric acid; 900 mL.
Apparatus 1:
50 rpm.
Time:
30 minutes.
Procedure—
Determine the amount of C
17H
19ClN
2S·HCl dissolved from UV absorbances at the wavelength of maximum absorbance at about 254 nm of filtered portions of the solution under test, suitably diluted with
Dissolution Medium, in comparison with a Standard solution having a known concentration of
USP Chlorpromazine Hydrochloride RS in the same medium.
Tolerances—
Not less than 80% (Q) of the labeled amount of C17H19ClN2S·HCl is dissolved in 30 minutes.
Other alkylated phenothiazines—
Transfer a portion of finely powdered Tablets, equivalent to 50 mg of chlorpromazine hydrochloride, to a stoppered centrifuge tube, add 10 mL of methanol, shake vigorously, and centrifuge (remove any sugar coating by prior washing with water). Proceed as directed in the test for
Other alkylated phenothiazines under
Chlorpromazine, beginning with “Dissolve a suitable quantity of
USP Chlorpromazine Hydrochloride RS.” The area and intensity of any spot, other than the principal spot, from the solution from the Tablets are not greater than those of the spot from the
Diluted standard solution (0.5%).
Assay—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 100 mg of chlorpromazine hydrochloride, to a 500-mL volumetric flask. Add about 200 mL of water and 5 mL of hydrochloric acid, insert the stopper, and shake for about 10 minutes. Dilute with water to volume, and mix. Filter a portion of the solution, discarding the first 50 mL of the filtrate. Treat 10.0 mL of the filtrate as directed in the
Assay under
Chlorpromazine Hydrochloride Injection, beginning with “Pipet 10 mL of the solution.” Calculate the quantity, in mg, of C
17H
19ClN
2S·HCl in the portion of Tablets taken by the formula:
12.5
C(
A254 
A277)
U / (
A254 A277)
S,
in which
C is the concentration, in µg per mL, of
USP Chlorpromazine Hydrochloride RS in the Standard solution, and the parenthetic expressions are the differences in the absorbances of the two solutions at the wavelengths indicated by the subscripts, for the solution from the Tablets (
U) and the Standard solution (
S), respectively.
