(kar' boe mer).
» Carbomer 1342 is a high molecular weight copolymer of acrylic acid and a long chain alkyl methacrylate cross-linked with allyl ethers of pentaerythritol. Carbomer 1342, previously dried in vacuum at 80 for 1 hour, contains not less than 52.0 percent and not more than 62.0 percent of carboxylic acid (COOH) groups. The viscosity of a neutralized 1.0 percent aqueous dispersion of Carbomer 1342 is between 9500 and 26,500 centipoises.
Packaging and storage Preserve in tight containers.
Labeling Label it to indicate that it is not intended for internal use. A carbomer copolymer manufactured using benzene and complying with the unique requirements of this monograph will be officially titled Carbomer 1342 and will not be referred to as Carbomer Copolymer.
Viscosity Proceed as directed in the test for Viscosity under Carbomer 934P, except to perform the test on a 1.0% aqueous dispersion (prepared by using 5.00 g instead of 2.50 g) and omit the 30-minute incubation of the solution before the titration. The viscosity is between 9500 and 26,500 centipoises.
Limit of benzene Proceed as directed in the test for Limit of benzene under Carbomer 934P, except to use about 50 mg of Carbomer 1342, accurately weighed, instead of about 1 g of Carbomer 934P, to prepare the Test solution. Calculate the percentage of benzene in the portion of Carbomer 1342 taken by the formula:
10(C/W)(rU / rS)in which C is the concentration, in µg per mL, of benzene in the Standard solution; W is the weight, in mg, of Carbomer 1342 taken to prepare the Test solution; and rU and rS are the benzene peak responses obtained from the Test solution and the Standard solution, respectively: not more than 0.2% is found.
Other requirements It meets the requirements for Identification, Loss on drying, Heavy metals, and Assay for carboxylic acid content under Carbomer 934P.