Standard preparation
Weigh accurately about 50mg of
USP Eucatropine Hydrochloride RS,dissolve in water,and dilute with water in a volumetric flask to 100mL.Dilute 10.0mLof this solution with water to 50.0mLto obtain a solution having a known concentration of about 100µg per mL.Prepare this solution fresh.
Procedure
Transfer duplicate 2-mLportions of the
Standard preparationand of the
Assay preparationto separate glass-stoppered,40-mLcentrifuge tubes.To one set of two tubes add 3mLof water and 1mLof sodium hydroxide solution (1in 100).Heat these tubes in a boiling water bath for 10minutes,and allow to cool to room temperature.To the remaining set of tubes,which provide the blanks for the
Standard preparationand
Assay preparation,respectively,add 4mLof water.To each tube add 2mLof approximately 0.2
Mceric sulfate in diluted sulfuric acid (prepared by dissolving 12.6g of ceric ammonium sulfate in 50mLof water and 3mLof sulfuric acid,and diluting with water to 100mL)and 20.0mLof isooctane.Shake by mechanical means for 15minutes,allow the layers to separate,and remove the isooctane from each tube.Concomitantly determine the absorbances of the isooctane solutions from the hydrolyzed aliquots in 1-cm cells at the wavelength of maximum absorbance at about 242nm,with a suitable spectrophotometer,against the respective blanks.Calculate the quantity,in mg,of C
17H
25NO
3·HCl in the portion of Ophthalmic Solution taken by the formula:
0.5C(AU/AS),
in which
Cis the concentration,in µg per mL,of
USP Eucatropine Hydrochloride RSin the
Standard preparation,and
AUand
ASare the absorbances of the solutions from the
Assay preparationand the
Standard preparation,respectively.