Polycarbophil
Polycarbophil.
Polycarbophil [9003-97-8].
»Polycarbophil is polyacrylic acid cross-linked with divinyl glycol.
Packaging and storage—
Preserve in tight containers.
Identification—
A:
Adispersion (1in 100)is orange with thymol blue TSand yellow with cresol red TS.
B:
Adjust a dispersion (1in 100)with 1Msodium hydroxide to a pHof about 7.5.Avery viscous gel is produced.
pHá791ñ—
To 1.0g add 100mLof water,and shake by mechanical means for 1hour:the pHof the mixture is not more than 4.0.
Loss on drying á731ñ—
Dry it in vacuum at 45
for 4hours:it loses not more than 1.5%of its weight.
for 4hours:it loses not more than 1.5%of its weight.
Residue on ignition á281ñ:
not more than 4.0%.
Absorbing power—
Transfer about 50mg,accurately weighed,to an accurately tared 50-mLcentrifuge tube fitted with a tight closure.Add 35mLof sodium bicarbonate solution (1.5in 100),and shake manually,venting as necessary to release liberated carbon dioxide.Shake and vent at least 3times.Close the tube tightly,and shake vigorously by mechanical means for 60minutes.Centrifuge at 2000rpm for 1hour.By means of a 50-mLsyringe fitted with a 13-gauge needle,draw off the supernatant taking care that the solid material is not disturbed.Repeat the process of the addition of 35mLof sodium bicarbonate solution,of the shaking,and of the withdrawing of supernatant.Accurately weigh the tube with its contents,and calculate the weight of the absorbed solution by subtracting the weight of Polycarbophil taken and the tare weight of the tube.The absorbed weight is not less than 62g per g of Polycarbophil on the dried basis.
Limit of acrylic acid—
pH3.0phosphate buffer—
Prepare 0.01Mmonobasic potassium phosphate,and adjust with phosphoric acid to a pHof 3.0±0.5.
Mobile phase—
Prepare a degassed solution consisting of pH3.0phosphate bufferand methanol (8:2).
Standard solution—
Dissolve an accurately weighed quantity of acrylic acid in water to obtain a solution containing 1.0mg per mL.Dilute quantitatively,and stepwise if necessary,with a 2.5%alum solution to obtain a solution having a known concentration of about 30µg per mL.
Test solution—
Transfer about 0.1g of Polycarbophil into a vial.Add 20mLof a 2.5%alum solution and mix.Heat at 50for 20minutes,then shake for 1hour,centrifuge,and filter.
for 20minutes,then shake for 1hour,centrifuge,and filter.
Chromatographic system
(see Chromatography á621ñ)—The liquid chromatograph is equipped with a 210-nm detector and a 3.9-mm ×30-cm column that contains packing L1.The flow rate is about 2.0mLper minute.Chromatograph the Standard solution,and record peak responses as directed for Procedure:the relative standard deviation for replicate injections of the Standard solutionis not more than 5.0%,and the tailing factor is not more than 2.5.
Procedure—
Separately inject equal volumes (about 20µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the response for the acrylic acid peak.Calculate the percentage of acrylic acid in the portion of Polycarbophil taken by the formula:
(0.002C/W)(rU/rS),
in which Cis the concentration,in µg per mL,of acrylic acid,Wis the weight,in g,of Polycarbophil taken,and rUand rSare the acrylic acid peak responses obtained from the Test solutionand the Standard solution,respectively:not more than 0.3%acrylic acid is found.
Limit of ethyl acetate—
Internal standard solution—
Dissolve an accurately weighed quantity of methyl ethyl ketone in methanol,and dilute quantitatively,and stepwise if necessary,to obtain a solution having a known concentration of about 0.075mg per mL.
Standard solution—
Dissolve 0.225mg,accurately weighed,of ethyl acetate into a 10-mLvolumetric flask.Add 2.0mLof the Internal standard solution,dilute with methanol to volume,and mix.
Test solution—
Transfer about 50mg of Polycarbophil into a 10-mLvolumetric flask.Add 2.0mLof the Internal standard solution,dilute with methanol to volume,and mix.
Chromatographic system
(see Chromatography á621ñ)—The gas chromatograph is equipped with a flame-ionization detector and a 10-ft.×2-mm column that contains 1%liquid phase G25on support S12.The column is maintained at about 160,and the injection port and detector block are maintained at about 250.The carrier gas is dry helium flowing at a rate of about 30mLper minute.Chromatograph the Standard solution,and record the chromatogram as directed for Procedure:the relative retention times are about 1.3for ethyl acetate,and 1.0for methyl ethyl ketone,and the relative standard deviation for replicate injections of the ethyl acetate peak is not more than 2%.
,and the injection port and detector block are maintained at about 250.The carrier gas is dry helium flowing at a rate of about 30mLper minute.Chromatograph the Standard solution,and record the chromatogram as directed for Procedure:the relative retention times are about 1.3for ethyl acetate,and 1.0for methyl ethyl ketone,and the relative standard deviation for replicate injections of the ethyl acetate peak is not more than 2%.
Procedure—
Separately inject equal volumes (about 2µL)of the Test solutionand the Standard solutioninto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the percentage of ethyl acetate in the portion of Polycarbophil taken by the formula:
(0.001C/W)(RU/RS),
in which Cis the concentration of ethyl acetate,in µg per mL,Wis the weight of Polycarbophil,in g,and RUand RSare the ratios of the responses of the ethyl acetate peak to the methyl ethyl ketone peak obtained from the Test solutionand the Standard solution,respectively:not more than 0.45%is found.
Organic volatile impurities,Method IVá467ñ:
meets the requirements.
Auxiliary Information—
Staff Liaison:Elena Gonikberg,Ph.D.,Scientist
Expert Committee:(PA4)Pharmaceutical Analysis 4
USP28–NF23Page 1574
Phone Number:1-301-816-8251