Propylene Glycol Alginate
»Propylene Glycol Alginate is a propylene glycol ester of alginic acid.Each g yields not less than 0.16and not more than 0.20g of carbon dioxide,calculated on the dried basis.
Packaging and storage— Preserve in well-closed containers.
Identification— Place 20mLof the saponified solution obtained in the determination of Esterified carboxyl groupsin a 250-mLconical flask,add 50mLof a solution of periodic acid (1in 50),swirl,and allow to stand for 30minutes.Add 2g of potassium iodide,titrate with sodium thiosulfate TSto a faint yellow color,dilute the mixture with water to 200mL,and mix to obtain the test solution for tests Aand B.
A: Dissolve 200mg of rosaniline hydrochloride,C20H20ClN3,in 120mLof hot water.Cool,add 2g of sodium bisulfite,NaHSO3,followed by 2mLof hydrochloric acid,and dilute with water to 200mLto obtain modified Schiff's reagent.(Store this solution in a brown bottle at 15or lower.)To 10mLof the test solution add 5mLof hydrochloric acid and 10mLof modified Schiff's reagent:a blue to blue-violet color,due to formaldehyde,develops in about 20minutes.
B: To 10mLof the test solution add 1mLof a saturated solution of piperazine and 0.5mLof sodium nitroferricyanide TS:a green color,due to acetaldehyde,develops.
Microbial limits á61ñ— The total bacterial count does not exceed 200cfu per g,and the tests for Salmonellaspecies and Escherichia coliare negative.
Loss on drying á731ñ— Dry it at 105for 4hours:it loses not more than 20.0%of its weight.
Ash— Weigh accurately about 3g in a tared crucible,and incinerate at 650±25until free from carbon.Cool in a desiccator,weigh,and determine the weight of the ash:not more than 10.0%,calculated on the dried basis,is found.
Lead á251ñ— Add 1.0g to 20mLof nitric acid in a 250-mLconical flask,mix,and heat carefully until the specimen is dissolved.Continue the heating until the volume is reduced to about 7mL.Cool rapidly to room temperature,transfer to a 100-mLvolumetric flask,dilute with water to volume,and mix.A50.0-mLportion of this solution contains not more than 5µg of lead (corresponding to not more than 0.001%of Pb),15mLof ammonium citrate solution,3mLof potassium cyanide solution,and 0.5mLof hydroxylamine hydrochloride solution being used for the test.After the first dithizone extractions,wash the combined chloroform layers with 5mLof water,discarding the water layer and continuing in the usual manner by extracting with 20mLof 0.2Nnitric acid.
Heavy metals,Method IIá231ñ: 0.004%,a platinum crucible being used for the ignition,and nitric acid being used in place of sulfuric acid to wet the test specimen.
Free carboxyl groups— Transfer about 1g,accurately weighed,to a 600-mLbeaker.Dissolve in 200mLof water,stirring by mechanical means for not less than 30minutes,and titrate with 0.1Nsodium hydroxide VSto a pHof 7.0,determining the endpoint potentiometrically.Calculate the weight,in g,of free carboxyl groups in the weight,W,in g,of specimen taken by the formula:
0.0044V/W,
in which Vis the volume,in mL,of 0.1Nsodium hydroxide consumed:the weight of free carboxyl groups found,calculated on the dried basis,is not more than 35%of the weight of carbon dioxide yielded by an equal weight of specimen in the Assay.
Esterified carboxyl groups— Transfer the solution obtained in the test for Free carboxyl groupswith the aid of water to a 1000-mLconical flask,add phenolphthalein TSand 50.0mLof 0.1Nsodium hydroxide VS,insert a stopper in the flask,mix,and allow to stand for 30minutes at ambient temperature.Titrate the excess sodium hydroxide with 0.1Nhydrochloric acid VSto a faint pink endpoint.Transfer the solution with the aid of water to a 600-mLbeaker,and complete the titration to a pHof 7.0,determining the endpoint potentiometrically.Calculate the weight,in g,of esterified carboxyl groups in the weight,W,in g,of specimen taken by the formula:
0.0044v/W,
in which vis the volume,in mL,of 0.1Nsodium hydroxide consumed:the weight of esterified carboxyl groups found,calculated on the dried basis,is between 40%and 85%of the weight of carbon dioxide yielded by an equal weight of specimen in the Assay.
Assay— Proceed as directed for Procedureunder Alginates Assay á311ñ,without preliminary drying of the Propylene Glycol Alginate.
Auxiliary Information— Staff Liaison:Ravi Ravichandran,Ph.D.,Senior Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 3068
Phone Number:1-301-816-8330