(C6H9NO)n
1-Ethenyl-2-pyrrolidinone homopolymer.
1-Vinyl-2-pyrrolidinone homopolymer [9003-39-8].

Packaging and storage— Preserve in tight containers.

USP Reference standards á11ñ— USP Crospovidone RS.

Identification—

pHá791ñ: between 5.0and 8.0,in an aqueous suspension (1in 100).

Water,Method Iá921ñ: not more than 5.0%.

Residue on ignition á281ñ: not more than 0.4%,a 2-g specimen being used.

Water-soluble substances— Transfer 25.0g of Crospovidone to a 400-mLbeaker,add 200mLof water,and stir on a magnetic stirrer,using a 5-cm stirring bar,for 1hour.Transfer to a 250-mLvolumetric flask with the aid of about 25mLof water,add water to volume,and mix.Allow the bulk of the solids to settle.Pass about 100mLof the relatively clear supernatant through a membrane filter having a 0.45-µm porosity,protected against clogging by superimposing a membrane filter having a 3-µm porosity.While filtering,stir the solution above the filter manually or with a mechanical stirrer,taking care not to physically damage the membrane filter.Transfer 50.0mLof the clear filtrate to a tared 100-mLbeaker,evaporate to dryness,and dry at 110for 3hours:the weight of the residue does not exceed 75mg (1.50%).

Heavy metals,Method IIá231ñ: 0.001%.

Vinylpyrrolidinone— Suspend 4.0g in 30mLof water,stir for 15minutes,centrifuge the suspension,and filter the slightly turbid upper layer through a sintered-glass,10-µm filter.Stir the lower layer with 50mLof water,centrifuge,and filter the upper layer through the same filter.Again stir the lower layer with 50mLof water,and filter similarly.Add 0.5g of sodium acetate to the combined filtrates,and titrate with 0.1Niodine VSuntil the color of iodine no longer fades.Add 3.0mLof 0.1Niodine VS,allow to stand for 10minutes,and titrate the excess iodine with 0.1Nsodium thiosulfate VS,adding 3mLof starch TSas the endpoint is approached.Perform a blank determination (see Residual Titrationsunder Titrimetry á541ñ),using the same total volume of the same 0.1Niodine VS,accurately measured,as was used for titrating the specimen.Before titrating the blank,adjust with acetic acid to the same pHas that of the specimen:not more than 0.72mLof 0.1Niodine is consumed,corresponding to not more than 0.1%of vinylpyrrolidinone.

Nitrogen content— Proceed as directed under Nitrogen Determination,Method IIá461ñ,using about 0.1g,accurately weighed,of Crospovidone.In the procedure,omit the use of hydrogen peroxide,and use 5g of a powdered mixture of potassium sulfate,cupric sulfate,and titanium dioxide (33:1:1),instead of potassium sulfate and cupric sulfate (10:1).Heat until a clear,light green solution is obtained,and heat for an additional 45minutes;and proceed as directed for Procedure,beginning with “Cautiously add to the digestion mixture 70mLof water.”

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 2994

Phone Number:1-301-816-8323