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 97.0percent and not more than 102.0percent of C15H21N3O2·C7H6O3,calculated on the dried basis.
Packaging and storage— Preserve in tight,light-resistant containers.Store at 25,excursions permitted between 15and 30.
Identification—
A: It responds to the Identificationtest under Physostigmine.
B: It responds to the tests for Salicylate á191ñ.
Specific rotation á781Sñ: between -91and -94.
Test solution: 10mg per mL,in water.
Loss on drying á731ñ— Dry it over silica gel for 24hours:it loses not more than 1.0%of its weight.
Residue on ignition á281ñ: negligible,from 100mg.
Sulfate— Precipitate the salicylic acid from 10mLof a cold,saturated solution of Physostigmine Salicylate with a slight excess of 3Nhydrochloric acid,filter,and to the filtrate add 5drops of barium chloride TS:no turbidity is produced immediately.
Readily carbonizable substances á271ñ— Dissolve 100mg in 5mLof sulfuric acid TS:at the end of 5minutes the solution has no more color than Matching Fluid I.
Assay— Dissolve about 250mg of Physostigmine Salicylate,accurately weighed,in 25mLof chloroform.Add 25mLof glacial acetic acid,and titrate with 0.02Nperchloric acid in dioxane VS,determining the endpoint potentiometrically.Perform a blank determination,and make any necessary correction.Each mLof 0.02Nperchloric acid is equivalent to 8.270mg of C15H21N3O2·C7H6O3.
Auxiliary Information— Staff Liaison:Salvador C.Salado,M.S.,Scientist and Latin American Liaison
Expert Committee:(PA3)Pharmaceutical Analysis 3
USP28–NF23Page 1555
Pharmacopeial Forum:Volume No.29(6)Page 1967
Phone Number:1-301-816-8165