Pyrrolo[2,3-b]indol-5-ol, 1,2,3,3a,8,8a-hexahydro-1,3a,8-trimethyl-, methylcarbamate (ester), (3aS-cis).
1,2,3,3a,8,8a-Hexahydro-1,3a,8-trimethylpyrrolo[2,3-b]indol-5-yl methylcarbamate [57-47-6].
» Physostigmine is an alkaloid usually obtained from the dried ripe seed of Physostigma venenosum Balfour (Fam. Leguminosae). It contains not less than 97.0 percent and not more than 102.0 percent of C15H21N3O2, calculated on the dried basis.
Packaging and storage Preserve in tight, light-resistant containers.
Identification It meets the requirements of the test for IdentificationOrganic Nitrogenous Bases 181, USP Physostigmine Salicylate RS being used, and 1 g of sodium bicarbonate being used in place of the 2 mL of 1 N sodium hydroxide specified.
Specific rotation 781S: between 236 and 246 (= 365 nm).
Test solution: 10 mg per mL, in methanol.
Loss on drying 731 Dry it over silica gel for 24 hours: it loses not more than 1.0% of its weight.
Residue on ignition 281: negligible, from 100 mg.
Readily carbonizable substances 271 Dissolve 100 mg in 5 mL of sulfuric acid TS: at the end of 5 minutes the solution has no more color than Matching Fluid I.
Assay Dissolve about 175 mg of Physostigmine, accurately weighed, in 25 mL of chloroform. Add 25 mL of glacial acetic acid, and titrate with 0.02 N perchloric acid in dioxane VS, determining the endpoint potentiometrically. Perform a blank determination, and make any necessary correction. Each mL of 0.02 N perchloric acid is equivalent to 5.507 mg of C15H21N3O2.
Auxiliary Information Please check for your question in the FAQs before contacting USP.
USP32NF27 Page 3300Pharmacopeial Forum: Volume No. 34(5) Page 1179