Physostigmine Salicylate

C15H21N3O2·C7H6O3

413.47

Pyrrolo[2,3-b]indol-5-ol, 1,2,3,3a,8,8a-hexahydro-1,3a,8-trimethyl-, methylcarbamate (ester), (3aS-cis)-, mono-(2-hydroxybenzoate).
Physostigmine monosalicylate

[57-64-7].

» Physostigmine Salicylate contains not less than 97.0 percent and not more than 102.0 percent of C15H21N3O2·C7H6O3, 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

—
USP Physostigmine Salicylate RS.

Identification—

A: It responds to the Identification test under Physostigmine.

B: It responds to the tests for Salicylate

191

Specific rotation

781S

: between

and

Test solution: 10 mg per mL, in water.

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.

Sulfate— Precipitate the salicylic acid from 10 mL of a cold, saturated solution of Physostigmine Salicylate with a slight excess of 3 N hydrochloric acid, filter, and to the filtrate add 5 drops of barium chloride TS: no turbidity is produced immediately.

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 250 mg of Physostigmine Salicylate, 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 8.270 mg of C15H21N3O2·C7H6O3.

Auxiliary Information— Please check for your question in the FAQs before contacting USP.

Topic/Question	Contact	Expert Committee
Monograph	Ravi Ravichandran, Ph.D. Senior Scientist 1-301-816-8330	(MDPP05) Monograph Development-Psychiatrics and Psychoactives
Reference Standards	Lili Wang, Technical Services Scientist 1-301-816-8129 RSTech@usp.org

USP32–NF27 Page 3300

Pharmacopeial Forum: Volume No. 34(5) Page 1179