Identification
A:
The solution employed for measurement of absorbance in the
Assayexhibits a maximum at 310±2nm.
B:
Dissolve 5g in 50mLof ether,extract the ether solution with 5mLof 3Nhydrochloric acid,and filter the extract.To the extract add 2mLof potassium thiocyanate solution (1in 2):a crystalline precipitate is formed,and when recrystallized from water and dried at 80

for 2hours,it melts between 130

and 132

(see
Melting Range or Temperature á741ñ).
Assay
Standard preparation
Prepare as directed in the Assayunder Tetracaine Ointment.
Assay preparation
Using an accurately weighed portion of Ophthalmic Ointment,prepare as directed in the Assayunder Tetracaine Ointment.
Procedure
Proceed as directed for Procedurein the Assayunder Tetracaine Ointment.