Physostigmine
(fye'' soe stig' meen).
Pyrrolo[2,3-b]indol-5-ol, 1,2,3,3a,8,8a-hexahydro-1,3a,8-trimethyl-, methylcarbamate (ester), (3aS-cis). Physostigmine. 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.
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: 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.
USP35NF30 Page 4316
Pharmacopeial Forum: Volume No. 34(5) Page 1179
|