Identification
A:
A1in 150solution of Injection in dilute sulfuric acid (1in 350)exhibits a vivid blue fluorescence.On the addition of a few drops of hydrochloric acid,the fluorescence disappears.
B:
Asolution of Injection (1in 4)is dextrorotatory.
C:
In the test for Chromatographic purity,the RFvalue of the principal spot obtained from the Test preparationcorresponds to that from the Standard preparation.
Chromatographic purity
Mix an accurately measured volume of Injection,equivalent to 80mg of quinidine gluconate,with 25mLof water,add 2drops of 2Nsulfuric acid,and extract with 50mLof ether,discarding the ether extract.To the aqueous solution add 2mLof 1Nsodium hydroxide,extract with 50mLof ether,wash the extract with 25mLof water,and discard the aqueous solutions.Evaporate the ether extract just to dryness,and dissolve the residue in 10mLof alcohol.Using this as the test solution,proceed as directed in the test for
Chromatographic purityunder
Quinidine Gluconate,beginning with Apply 10-µLportions of the
Test preparation.
Assay
Standard preparation
Transfer about 26mg of USP Quinidine Gluconate RS,accurately weighed,to a 100-mLvolumetric flask,dissolve in and dilute with Mobile phaseto volume,and mix.
Assay preparation
Transfer an accurately measured volume of Injection,equivalent to about 400mg of quinidine gluconate,to a 50-mLvolumetric flask,add methanol to volume,and mix.Transfer 3.0mLof this solution to a 100-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.
Procedure
(see
Chromatography á621ñ)Inject equal volumes (about 50µL)of the
Standard preparationand the
Assay preparationinto a chromatograph equipped with a 235-nm detector and a 3.9-mm ×30-cm column that contains packing L1.Calculate the quantity,in mg,of the
Sum of quinidine gluconate and dihydroquinidine gluconatein each mLof the Injection taken by the formula:
(5000/3)(C/V)(rb,U+rd,U)/(rb,S+rd,S),
in which
Cis the concentration,in mg per mL,of USP Quinidine Gluconate RSin the
Standard preparation,
Vis the volume,in mL,of Injection taken,
rb,Uand
rb,Sare the peak responses of quinidine obtained from the
Assay preparationand the
Standard preparation,respectively,and
rd,Uand
rd,Sare the peak responses of dihydroquinidine obtained from the
Assay preparationand the
Standard preparation,respectively.