Promazine Hydrochloride
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C17H20N2S·HCl 320.88

10H-Phenothiazine-10-propanamine, N,N-dimethyl-, monohydrochloride.
10-3-(Dimethylamino)propylphenothiazine monohydrochloride [53-60-1].
» Promazine Hydrochloride, dried at 105 for 2 hours, contains not less than 98.0 percent and not more than 102.0 percent of C17H20N2S·HCl.
Packaging and storage— Preserve in tight, light-resistant containers.
Completeness and clarity of solution— A solution of it (1 in 10) and a 1 in 10 solution of it in chloroform are practically clear and show not more than a light yellow color.
note—Throughout the following procedures, protect test or assay specimens, the Reference Standard, and solutions containing them, by conducting the procedures without delay, under subdued light, or using low-actinic glassware.
B: Determine the absorbance of the assay solution employed for measurement of absorbance in the Assay at 301 nm, using 0.1 N hydrochloric acid as the blank. Similarly determine the absorbance of a 1 in 10 dilution of this solution, prepared with the same acid, at the wavelength of maximum absorbance at about 252 nm: the ratio 10(A252/A301) is between 7.1 and 7.9.
C: It responds to the tests for Chloride 191.
Melting range, Class I 741: between 172 and 182, but the range between beginning and end of melting does not exceed 3.
pH 791: between 4.2 and 5.2, in a solution (1 in 20).
Loss on drying 731 Dry it at 105 for 2 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Selenium 291 The absorbance of the solution from the Test Solution, prepared with 100 mg of Promazine Hydrochloride and 200 mg of magnesium oxide, is not greater than one-half that from the Standard Solution (0.003%).
Chromatographic purity— [note—Perform this test under conditions of subdued light and with no unnecessary delays between the preparation of the solutions and the development of the chromatographic plate.]
Developing solvent— Mix 95 volumes of toluene with 15 volumes of alcohol and 1 volume of ammonium hydroxide.
Standard preparations— Dissolve an accurately weighed quantity of USP Promazine Hydrochloride RS in methanol to obtain Standard preparation A having a known concentration of 0.4 mg per mL. Dilute quantitatively with methanol to obtain Standard preparations having the following compositions:
Standard preparation Dilution Concentration (µg RS per mL) Percentage (%, for comparison with test specimens)
A (undiluted) 400 2.0
B (1 in 2) 200 1.0
C (3 in 10) 120 0.6
D (1 in 10) 40 0.2
Test preparation— Dissolve an accurately weighed quantity of Promazine Hydrochloride in methanol to obtain a solution containing 20 mg per mL.
Procedure— Apply separately 10 µL of the Test preparation and 10 µL of each Standard preparation to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture, and allow to dry. Position the plate in a chromatographic chamber and develop the chromatograms in the Developing solvent until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow the solvent to evaporate by air drying for 15 minutes. Examine the plate under short-wavelength UV light. Compare the intensities of any secondary spots observed in the chromatogram of the Test preparation with those of the principal spots in the chromatograms of the Standard preparations: the sum of the intensities of secondary spots obtained from the Test preparation corresponds to not more than 2.0% of related compounds, with no single impurity corresponding to more than 1.0%.
Assay— [note—Use low-actinic glassware.] Transfer about 50 mg of Promazine Hydrochloride, previously dried and accurately weighed, to a 1000-mL volumetric flask, add 0.1 N hydrochloric acid to volume, and mix. Without delay, concomitantly determine the absorbances of this solution and of a Standard solution of USP Promazine Hydrochloride RS in the same medium having a known concentration of about 50 µg per mL in 1-cm cells at the wavelength of maximum absorbance at about 301 nm, with a suitable spectrophotometer, using 0.1 N hydrochloric acid as the blank. Calculate the quantity, in mg, of C17H20N2S·HCl in the portion of Promazine Hydrochloride taken by the formula:
C(AU / AS)
in which C is the concentration, in µg per mL, of USP Promazine Hydrochloride RS in the Standard solution, and AU and AS are the absorbances of the solution of Promazine Hydrochloride and the Standard solution, respectively.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Daniel K. Bempong, Ph.D.
Senior Scientist
(MDPS05) Monograph Development-Pulmonary and Steroids
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 3403
Pharmacopeial Forum: Volume No. 29(5) Page 1566
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.