(meth' a done hye'' droe klor' ide).
3-Heptanone, 6-(dimethylamino)-4,4-diphenyl-, hydrochloride.
6-(Dimethylamino)-4,4-diphenyl-3-heptanone hydrochloride [1095-90-5].
» Methadone Hydrochloride contains not less than 98.5 percent and not more than 100.5 percent of C21H27NO·HCl, calculated on the dried basis.
Packaging and storage Preserve in tight, light-resistant containers. Store at 25, excursions permitted between 15 and 30.
USP Reference standards 11
B: A solution of it responds to the tests for Chloride 191.
pH 791: between 4.5 and 6.5, in a solution (1 in 100).
Loss on drying 731 Dry about 500 mg, accurately weighed, at 105 for 1 hour: it loses not more than 0.3% of its weight.
Residue on ignition 281: not more than 0.1%.
Ordinary impurities 466
Test solution: alcohol.
Standard solution: alcohol.
Eluant: a mixture of methanol and ammonium hydroxide (100:1.5).
Limits The sum of the intensities of all secondary spots obtained from the Test solution corresponds to not more than 1.0%.
Assay Dissolve about 500 mg of Methadone Hydrochloride, accurately weighed, in a mixture of 10 mL of glacial acetic acid and 10 mL of mercuric acetate TS, warming slightly if necessary to effect solution. Cool the solution to room temperature, add 10 mL of dioxane, then add crystal violet TS, and titrate rapidly with 0.1 N perchloric acid VS. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 34.59 mg of C21H27NO·HCl.
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USP35NF30 Page 3839Pharmacopeial Forum: Volume No. 29(6) Page 1929