Iodoquinol
;)
8-Quinolinol,5,7-diiodo-.
5,7-Diiodo-8-quinolinol [83-73-8].
»Iodoquinol contains not less than 96.0percent and not more than 100.5percent of C9H5I2NO,calculated on the dried basis.
Packaging and storage—
Preserve in well-closed containers.
Identification—
A:
Prepare a 1in 200solution in carbon disulfide,warming slightly,if necessary,to effect complete solution:the IRabsorption spectrum of this solution,in a 3-mm sodium chloride cell,carbon disulfide being used as the blank,in the region from 7µm to 11µm exhibits absorption maxima and minima only at the same wavelengths as that of a similar solution of USP Iodoquinol RS,concomitantly measured.
B:
Warm a small quantity of it with 1mLof sulfuric acid:violet vapors of iodine are evolved.
Loss on drying á731ñ—
Dry it over silica gel for 4hours:it loses not more than 0.5%of its weight.
Residue on ignition á281ñ:
not more than 0.5%.
Free iodine and iodide—
Shake 1.0g with 20mLof water for 30seconds,allow to stand for 5minutes,and filter.To 10mLof the filtrate add 1mLof 2Nsulfuric acid,then add 2mLof chloroform,and shake:no violet color appears in the chloroform (free iodine).To the mixture add 5mLof 2Nsulfuric acid and 1mLof potassium dichromate TS,and shake for 15seconds:the color in the chloroform layer is not deeper than that produced in a control test made in the following manner.Dilute 2mLof potassium iodide solution (1in 6000)with water to 10mL,add 6mLof 2Nsulfuric acid,1mLof potassium dichromate TS,and 2mLof chloroform,and shake for 15seconds (0.05%of iodide).
Assay—
Using about 14mg of Iodoquinol,accurately weighed,proceed as directed under Oxygen Flask Combustion á471ñ,using a mixture of 10mLof sodium hydroxide solution (1in 100)and 1mLof freshly prepared sodium bisulfite solution (1in 100)as the absorbing liquid.When the combustion is complete,place a few mLof water around the stopper of the flask,loosen the stopper,then rinse the stopper,the specimen holder,and the sides of the flask with about 20mLof water,added in small portions.Add 1mLof an oxidizing solution prepared by adding 5mLof bromine to 100mLof a 1in 10solution of sodium acetate in glacial acetic acid.Insert the stopper in the flask,and shake vigorously for 1minute.Add 0.5mLof formic acid,replace the stopper,and shake vigorously for 1minute.Remove the stopper,and rinse the stopper,the specimen holder,and the sides of the flask with several small portions of water.Bubble nitrogen through the flask to remove the oxygen and excess bromine,add 500mg of potassium iodide,swirl to dissolve,add 3mLof 2Nsulfuric acid,swirl to mix,and allow to stand for 2minutes.Titrate with 0.02Nsodium thiosulfate VS,adding 3mLof starch TSas the endpoint is approached.Each mLof 0.02Nsodium thiosulfate is equivalent to 0.6616mg of C9H5I2NO.
Auxiliary Information—
Staff Liaison:Behnam Davani,Ph.D.,MBA,Senior Scientist
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 1043
Phone Number:1-301-816-8394