Amino Methacrylate Copolymer
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» Amino Methacrylate Copolymer is a 
1S (NF27)polymerized copolymer of (2-dimethylaminoethyl) methacrylate, butyl methacrylate, and methyl methacrylate. This copolymer has a mean relative molecular mass of about 150,000. The ratio of (2-dimethylaminoethyl) methacrylate groups to butyl methacrylate and methyl methacrylate groups is about 2:1:1.1S (NF27)It contains not less than 20.8 percent and not more than 25.5 percent of dimethylaminoethyl groups (C4H10N), calculated on the dried basis.
1S (NF27)polymerized copolymer of (2-dimethylaminoethyl) methacrylate, butyl methacrylate, and methyl methacrylate. This copolymer has a mean relative molecular mass of about 150,000. The ratio of (2-dimethylaminoethyl) methacrylate groups to butyl methacrylate and methyl methacrylate groups is about 2:1:1.1S (NF27)It contains not less than 20.8 percent and not more than 25.5 percent of dimethylaminoethyl groups (C4H10N), calculated on the dried basis.
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Packaging and storage—
Preserve in tight containers, and store at a temperature below1S (NF27)25
.
Color of solution—
The absorbance of the Test solution prepared in the test under Viscosity, determined in a 1-cm cell at 420 nm in a suitable spectrophotometer, is not greater than 0.300. Use water as the blank.
Identification—
B:
Pour 1 mL of the Test solution prepared in the test under Viscosity onto a glass plate and allow the solvent to evaporate: a clear, colorless film results.
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Viscosity 
911
—
Test solution—
Dissolve 12.5 g in a mixture of 35.0 g of acetone and 52.5 g of isopropyl alcohol. [Note—Reserve a portion of this solution for the Color of solution test.]
Procedure—
Equip a rotational viscometer validated for measuring low-viscosity liquids. This low-viscosity system consists of a measuring cylinder and a spindle.1 Transfer an appropriate volume of the Test solution into the measuring cylinder, and adjust the temperature of the solution and the adapter to 20 ± 0.1. With the spindle rotating at an appropriate rpm that yields a shear rate of 36.7 s
1, immediately observe and record the scale reading. Convert the scale reading to mPa·s by multiplying the reading by the constant for the viscometer, the adapter system, and the speed used. The viscosity is between 3 and 6 mPa·s.1S (USP27)
Equip a rotational viscometer validated for measuring low-viscosity liquids. This low-viscosity system consists of a measuring cylinder and a spindle.1 Transfer an appropriate volume of the Test solution into the measuring cylinder, and adjust the temperature of the solution and the adapter to 20 ± 0.1. With the spindle rotating at an appropriate rpm that yields a shear rate of 36.7 s1, immediately observe and record the scale reading. Convert the scale reading to mPa·s by multiplying the reading by the constant for the viscometer, the adapter system, and the speed used. The viscosity is between 3 and 6 mPa·s.1S (USP27)
Loss on drying 731—
Dry it at 110 for 3 hours: it loses not more than 2.0% of its weight.
731—
Dry it at 110 for 3 hours: it loses not more than 2.0% of its weight.
Residue on ignition 281:
not more than 0.1%.
281:
not more than 0.1%.
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Limit of monomers—
Test 1, Limit of Butyl methacrylate and methyl methacrylate—
pH 2.0 Phosphate buffer (0.0625 M)—
Prepare an aqueous solution containing 8.9 g of anhydrous dibasic sodium phosphate and 8.5 g of monobasic potassium phosphate per L. Adjust with phosphoric acid to a pH of 2.0.
Mobile phase—
Prepare a mixture of methanol and pH 2.0 Phosphate buffer (0.0625 M) (55:45).
Standard solution—
Dissolve about 20 mg of butyl methacrylate, and about 10 mg of methyl methacrylate, accurately weighed, in 3 mL of n-butanol. Dilute to 10 mL with a solvent mixture of pH 2.0 Phosphate buffer (0.0625 M) and acetonitrile (60:40). Dilute 1.0 mL of this solution to 250.0 mL with the same solvent mixture, and mix. This solution contains about 8 µg per mL of butyl methylcrylate and 4 µg per mL of methyl methacrylate.1S (NF27)
Dissolve about 20 mg of butyl methacrylate, and about 10 mg of methyl methacrylate, accurately weighed, in 3 mL of n-butanol. Dilute to 10 mL with a solvent mixture of pH 2.0 Phosphate buffer (0.0625 M) and acetonitrile (60:40). Dilute 1.0 mL of this solution to 250.0 mL with the same solvent mixture, and mix. This solution contains about 8 µg per mL of butyl methylcrylate and 4 µg per mL of methyl methacrylate.1S (NF27)
Test solution—
Dissolve about 1.0 g of Amino Methacrylate Copolymer, accurately weighed, in a solvent mixture of pH 2.0 Phosphate buffer (0.0625M) and acetonitrile (60:40), dilute with the same solvent mixture to 50.0 mL, and mix.1S (NF27)
Dissolve about 1.0 g of Amino Methacrylate Copolymer, accurately weighed, in a solvent mixture of pH 2.0 Phosphate buffer (0.0625M) and acetonitrile (60:40), dilute with the same solvent mixture to 50.0 mL, and mix.1S (NF27)
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 205-nm detector and a 4.6-mm × 12-cm column that contains packing L1. The flow rate is about 2 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the resolution, R, between butyl methacrylate and methyl methacrylate is not less than 10; and the relative standard deviation for replicate injections is not more than 3.0%.
621)—
The liquid chromatograph is equipped with a 205-nm detector and a 4.6-mm × 12-cm column that contains packing L1. The flow rate is about 2 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the resolution, R, between butyl methacrylate and methyl methacrylate is not less than 10; and the relative standard deviation for replicate injections is not more than 3.0%.
Procedure—
Separately inject equal volumes (about 50 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the percentage of each monomer in the portion of Amino Methacrylate Copolymer taken by the formula:
6 is a factor converting µg to g; 50 is the volume, in mL, of the Test solution;1S (NF27) C is the concentration, in µg per mL, of each monomer in the Standard solution; W is the weight, in g, of Amino Methaccrylate Copolymer taken to prepare the Test solution;1S (NF27)and rU and rS are the peak responses of each monomer obtained from the Test solution and the Standard solution, respectively: not more than 0.1% of each monomer is found.
Calculate the percentage of each monomer in the portion of Amino Methacrylate Copolymer taken by the formula:
100(106)(50)(C / W) (rU / rS)
in which 106)(50)(C / W) (rU / rS)6 is a factor converting µg to g; 50 is the volume, in mL, of the Test solution;1S (NF27) C is the concentration, in µg per mL, of each monomer in the Standard solution; W is the weight, in g, of Amino Methaccrylate Copolymer taken to prepare the Test solution;1S (NF27)and rU and rS are the peak responses of each monomer obtained from the Test solution and the Standard solution, respectively: not more than 0.1% of each monomer is found.
Test 2, Limit of 2-dimethylaminoethyl methacrylate—
Monobasic potassium phosphate solution (0.025 M)—
Prepare an aqueous solution containing 3.4 g of monobasic potassium phosphate per L.
Mobile phase—
Prepare a mixture of tetrahydrofuran and Monobasic potassium phosphate solution (0.025 M) (75:25).1S (NF27)
Prepare a mixture of tetrahydrofuran and Monobasic potassium phosphate solution (0.025 M) (75:25).1S (NF27)
Standard solution—
Prepare a solution in tetrahydrofuran having a concentration of about 200 µg per mL of (2-dimethylaminoethyl) methacrylate. Dilute 2.0 mL of the solution to 50.0 mL with tetrahydrofuran, and mix. This solution contains about 8 µg per mL of (2-dimethylaminoethyl) methacrylate.1S (NF27)
This solution contains about 8 µg per mL of (2-dimethylaminoethyl) methacrylate.1S (NF27)
Test solution—
Dissolve about 1.0 g of Amino Methacrylate Copolymer, accurately weighed, in tetrahydrofuran, dilute with tetrahydrofuran to 50.0 mL, and mix.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 215-nm detector and a 4.6-mm × 12-cm column that contains packing L8. The flow rate is about 2 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 2.0%.
621)—
The liquid chromatograph is equipped with a 215-nm detector and a 4.6-mm × 12-cm column that contains packing L8. The flow rate is about 2 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 50 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the response for the major peak. Calculate the percentage of (2-dimethylaminoethyl) methacrylate in the portion of Amino Methacrylate Copolymer taken by the formula:
6 is a factor converting µg to g; 50 is the volume, in mL, of the Test solution;1S (NF27) C is the concentration, in µg per mL, of the monomer in the Standard solution; W is the weight, in g, of Amino Methacrylate Copolymer taken to prepare the Test solution;1S (NF27)and rU and rS are the peak responses of (2-dimethylaminoethyl) methacrylate obtained from the Test solution and the Standard solution, respectively: not more than 0.1% is found.
Calculate the percentage of (2-dimethylaminoethyl) methacrylate in the portion of Amino Methacrylate Copolymer taken by the formula:
100(106)(50)(C / W) (rU / rS)
in which 106)(50)(C / W) (rU / rS)6 is a factor converting µg to g; 50 is the volume, in mL, of the Test solution;1S (NF27) C is the concentration, in µg per mL, of the monomer in the Standard solution; W is the weight, in g, of Amino Methacrylate Copolymer taken to prepare the Test solution;1S (NF27)and rU and rS are the peak responses of (2-dimethylaminoethyl) methacrylate obtained from the Test solution and the Standard solution, respectively: not more than 0.1% is found.
Assay—
Dissolve 0.20 g in a mixture of 4 mL of water and 96 mL of glacial acetic acid, and mix. Titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically (see Titrimetry 541). One mL of 0.1 N perchloric acid is equivalent to 7.21 mg of dimethylaminoethyl groups (C4H10N).
541). One mL of 0.1 N perchloric acid is equivalent to 7.21 mg of dimethylaminoethyl groups (C4H10N).
1
The measuring cylinder has an internal diameter of 2.8 cm and a depth of 13.5 cm; the spindle is 2.5 cm in diameter and 9.1 cm in height and has a shaft that is 0.4 cm in diameter. A commercial instrument is available, either as an ultra-low viscosity adapter from Brookfield or as an equivalent viscometer, as long as the requirement of shear rate is met.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
Chromatographic Column—
| Topic/Question | Contact | Expert Committee |
| Monograph | Hong Wang, Ph.D.
Scientist 1-301-816-8351 |
(EM205) Excipient Monographs 2 |
| Reference Standards | Lili Wang, Technical Services Scientist 1-301-816-8129 RSTech@usp.org |
USP32–NF27 Page 1162
Pharmacopeial Forum: Volume No. 34(2) Page 326
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.