Sorbitol Solution
»Sorbitol Solution is an aqueous solution containing not less than 64.0percent of D-sorbitol (C6H14O6).The amounts of total sugars,other polyhydric alcohols,and any hexitol anhydrides,if detected,are not included in the requirements nor in the calculated amount underOther Impurities.
Packaging and storage—
Preserve in well-closed containers.Do not store below 20
.
.
Identification—
A:
Dissolve 1.4g of Sorbitol Solution in 75mLof water.Transfer 3mLof this solution to a 15-cm test tube,add 3mLof freshly prepared catechol solution (1in 10),mix,add 6mLof sulfuric acid,mix again,and gently heat the tube in a flame for about 30seconds:a deep pink or wine color appears.
B:
The retention time of the major peak in the chromatogram of the Assay preparationcorresponds to that in the chromatogram of the Standard preparation,as obtained in the Assay.
pHá791ñ:
between 5.0and 7.5,in a 14%(w/w)solution of Sorbitol Solution in carbon dioxide–free water.
Water,Method Iá921ñ:
between 28.5%and 31.5%.
Residue on ignition á281ñ:
not more than 0.1%,calculated on the anhydrous basis,determined on a 2-g portion,accurately weighed.
Reducing sugars—
To an amount of Sorbitol Solution,equivalent to 3.3g on the anhydrous basis,add 3mLof water,20.0mLof cupric citrate TS,and a few glass beads.Heat so that boiling begins after 4minutes,and maintain boiling for 3minutes.Cool rapidly,and add 40mLof diluted acetic acid,60mLof water,and 20.0mLof 0.05Niodine VS.With continuous shaking,add 25mLof a mixture of 6mLof hydrochloric acid and 94mLof water.When the precipitate has dissolved,titrate the excess of iodine with 0.05Nsodium thiosulfate VSusing 2mLof starch TS,added towards the end of the titration,as an indicator.Not less than 12.8mLof 0.05Nsodium thiosulfate VSis required,corresponding to not more than 0.3%of reducing sugars,on the anhydrous basis,as glucose.The amount determined in this test is not included in the calculated amount underOther Impurities.
Limit of nickel—
Test solution—
Dissolve 20.0g of Sorbitol Solution in diluted acetic acid,and dilute with diluted acetic acid to 100.0mL.Add 2.0mLof a saturated ammonium pyrrolidine dithiocarbamate solution (containing about 10g of ammonium pyrrolidine dithiocarbamate per L)and 10.0mLof methyl isobutyl ketone,and shake for 30seconds.Protect from bright light.Allow the two layers to separate,and use the methyl isobutyl ketone layer.
Blank solution—
Prepare as directed forTest solution,except to omit the use of the Sorbitol Solution.
Standard solutions—
Prepare as directed forTest solution,except to prepare three solutions by adding 0.5mL,1.0mL,and 1.5mLof nickel standard solution TS.
Procedure—
Set the instrument to zero using the Blank solution.Concomitantly determine the absorbances of the Standard solutions and the Test solution at least three times each,at the wavelength of maximum absorbance at 232.0nm,with a suitable atomic absorption spectrophotometer (see Spectrophotometry and Light-Scattering á851ñ)equipped with a nickel hollow-cathode lamp and an air–acetylene flame.Record the average of the steady readings for each of the Standard solutions and the Test solution.Between each measurement,aspirate the Blank solution,and ascertain that the reading returns to zero.Plot the absorbances of the Standard solutions and the Test solution versus the added quantity of nickel.Extrapolate the line joining the points on the graph until it meets the concentration axis.The distance between this point and the intersection of the axes represents the concentration of nickel in the Test solution.Not more than 1µg per g,calculated on the anhydrous basis,is found.
Assay—
Mobile phase,Resolution solution,Standard preparation,and Chromatographic system—
Proceed as directed in theAssayunderSorbitol.
Assay preparation—
Accurately weigh about 0.12g of Sorbitol Solution,dissolve in and dilute with water to about 20g.Accurately record the final solution weight,and mix thoroughly.
Procedure—
Proceed as directed in theAssayunderSorbitol.Calculate the percentage of D-sorbitol (C6H14O6)in the portion of Sorbitol Solution taken by the formula:
100(CS/CU)(rU/rS),
in which CSis the concentration,in mg per g,of USP Sorbitol RSin theStandard preparation;CUis the concentration,in mg per g,of Sorbitol Solution in theAssay preparation;and rUand rSare the peak responses obtained from theAssay preparationand theStandard preparation,respectively.
Auxiliary Information—
Staff Liaison:Catherine Sheehan,B.Sc.,Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 1795
Pharmacopeial Forum:Volume No.30(3)Page 929
Phone Number:1-301-816-8262