Identification—
A:
Transfer a portion of Ophthalmic Ointment, equivalent to about 50 mg of atropine sulfate, to a suitable separator, and dissolve in 25 mL of ether. Add 25 mL of 0.01 N hydrochloric acid, shake vigorously, allow the layers to separate, and discard the organic phase. Heat the aqueous phase gently on a steam bath while passing nitrogen through the solution, to expel any residual ether. Proceed as directed under
Identification—Organic Nitrogenous Bases 
181
, beginning with “In a second separator dissolve 50 mg.”
B:
Transfer about 5 g of Ophthalmic Ointment to a separator, dissolve in 50 mL of ether, and extract with 20 mL of water: the extracted solution so obtained responds to the tests for
Sulfate 191.
Assay—
Proceed with Ophthalmic Ointment as directed in the
Assay under
Atropine Sulfate Ophthalmic Solution, but in preparing the
Assay preparation, weigh accurately a portion of Ophthalmic Ointment, equivalent to about 10 mg of atropine sulfate, transfer to a separator containing 50 mL of ether, shake to dissolve, extract with three 25-mL portions of 0.1 M sulfuric acid, collect the acid extracts in a 100-mL volumetric flask, dilute with 0.1 M sulfuric acid to volume, and mix. Proceed as directed for the
Assay preparation in the
Assay under
Atropine Sulfate Ophthalmic Solution, beginning with “Pipet 10 mL of this solution into a separator.” Calculate the quantity, in mg, of atropine sulfate [(C
17H
23NO
3)
2·H
2SO
4·H
2O] in the portion of Ophthalmic Ointment taken by the formula given therein.
