Methdilazine Hydrochloride
C18H20N2S·HCl 332.89

10H-Phenothiazine, 10-[(1-methyl-3-pyrrolidinyl)methyl]-, monohydrochloride.
10-[(1-Methyl-3-pyrrolidinyl)methyl]phenothiazine monohydrochloride [1229-35-2].
» Methdilazine Hydrochloride contains not less than 97.0 percent and not more than 103.0 percent of C18H20N2S·HCl, calculated on the dried basis.
Packaging and storage— Preserve in tight, light-resistant containers.
USP Reference standards 11
USP Methdilazine Hydrochloride RS
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: Ultraviolet Absorption 197U
Solution: 5 µg per mL.
Medium: water.
C: A solution of it responds to the tests for Chloride 191.
Melting range, Class I 741: between 184 and 190.
pH 791: between 4.8 and 6.0, in a solution (1 in 100).
Loss on drying 731 Dry it in vacuum at 65 for 16 hours: it loses not more than 1.0% of its weight.
Residue on ignition 281: not more than 0.5%.
Selenium 291 The absorbance of the solution from the Test Solution, prepared with 100 mg of Methdilazine Hydrochloride and 100 mg of magnesium oxide, is not greater than one-half that from the Standard Solution (0.003%).
Ordinary impurities 466
Test solution: methanol.
Standard solution: methanol.
Application volume: 10 µL.
Eluant: a mixture of toluene, isopropyl alcohol, and ammonium hydroxide (70:29:1), in a nonequilibrated chamber.
Visualization: 5.
Assay— Transfer about 100 mg of Methdilazine Hydrochloride, accurately weighed, to a 1000-mL volumetric flask, add water to volume, and mix. Transfer 5.0 mL of this solution to a 100-mL volumetric flask, dilute with water to volume, and mix. Concomitantly determine the absorbances of this solution and of a Standard solution of USP Methdilazine Hydrochloride RS in the same medium having a known concentration of about 5 µg per mL, in 1-cm cells at 252 and 275 nm, with a suitable spectrophotometer, using water as the blank. Calculate the quantity, in mg, of C18H20N2S·HCl in the portion of Methdilazine Hydrochloride taken by the formula:
20C(A252 A275)U / (A252 A275)S
in which C is the concentration, in µg per mL, of USP Methdilazine 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 of Methdilazine Hydrochloride (U) and the Standard solution (S), respectively.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Feiwen Mao, M.S.
(MDOOD05) Monograph Development-Ophthalmics Oncologics and Dermatologicals
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 2919
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.