Identification—
A:
The solution employed for measurement of absorbance in the
Assay exhibits a maximum at 310 ± 2 nm.
B:
Dissolve 5 g in 50 mL of ether, extract the ether solution with 5 mL of 3 N hydrochloric acid, and filter the extract. To the extract add 2 mL of potassium thiocyanate solution (1 in 2): a crystalline precipitate is formed, and when recrystallized from water and dried at 80
for 2 hours, it melts between 130
and 132
(see
Melting Range or Temperature 
741
).
Assay—
Standard preparation—
Prepare as directed in the Assay under Tetracaine Ointment.
Assay preparation—
Using an accurately weighed portion of Ophthalmic Ointment, prepare as directed in the Assay under Tetracaine Ointment.
Procedure—
Proceed as directed for Procedure in the Assay under Tetracaine Ointment.
