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C19H24N2OS 328.47

10H-Phenothiazine-10-propanamine, 2-methoxy-N,N,-trimethyl-, ()-.
()-10-[3-(Dimethylamino)-2-methylpropyl]-2-methoxyphenothiazine [60-99-1].
» Methotrimeprazine contains not less than 98.0 percent and not more than 101.0 percent of C19H24N2OS, calculated on the dried basis.
Packaging and storage— Preserve in well-closed, light-resistant containers. Store at 25, excursions permitted between 15 and 30.
USP Reference standards 11
USP Methotrimeprazine RS
note—Throughout the following procedures, protect test or assay specimens, the USP Reference Standard, and the solutions containing them, by conducting the procedures without delay, under subdued light, or using low-actinic glassware.
B: Ultraviolet Absorption 197U
Solution: 7 µg per mL.
Medium: alcohol.
Absorptivities at 255 nm, calculated on the dried basis, do not differ by more than 3.0%.
Specific rotation 781S: between 15 and 18.
Test solution: 50 mg per mL, in chloroform.
Loss on drying 731 Dry it at 100 for 3 hours: it loses not more than 0.5% of its weight.
Selenium 291 The absorbance of the solution from the Test Solution, prepared with 100 mg of Methotrimeprazine and 100 mg of magnesium oxide, is not greater than one-half that from the Standard Solution (0.003%).
Assay— Dissolve about 700 mg of Methotrimeprazine, accurately weighed, in 100 mL of chloroform, add 1 drop of a 1 in 500 solution of crystal violet in chloroform, and titrate with 0.1 N perchloric acid VS to the first disappearance of the violet tinge. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 32.85 mg of C19H24N2OS.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Clydewyn M. Anthony, Ph.D.
(MDCCA05) Monograph Development-Cough Cold and Analgesics
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 2930
Pharmacopeial Forum: Volume No. 29(6) Page 1931