Product name :  Carbopol

IUPAC Name: prop-2-enoic acid

CAS Number:  9007-20-9

Chemical Formula  : C₃H₄O₂

Items                                                Properties

Appearance                                    Fluffy, white, mildly acidic polymer
Bulk Density                                   Approximately 208 kg/m3 (13 lbs.ft3) *
Specific gravity                               1.41
Moisture content                            2.0% maximum
Equilibrium moisture content     8-10% (at 50% relative humidity)
PKa                                                  6.0 ± 0.5
pH of 1.0% water dispersion      2.5 - 3.0
pH of 0.5% water dispersion      2.7 - 3.5
Equivalent weight                          76 ± 4
Ash content                                    0.009 ppm (average) **
Glass transition temperature     100-105C (212-221F)
 

Characteristics and Application :

In the recent decades, there has been considerable interest in using Carbopol as an excipient in a diverse range of pharmaceutical applications.
Carbopol polymers are polymers of acrylic acid cross-linked with polyalkenyl ethers or divinyl glycol. They are produced from primary polymer particles of about 0.2 to 6.0 micron average diameter. The flocculated agglomerates cannot be broken into the ultimate particles when produced. Each particle can be viewed as a network structure of polymer chains interconnected via cross-linking.

The readily water-swellable Carbopol polymers are used in a diverse range of pharmaceutical applications to provide:
· Controlled release in tablets.

· Bioadhesion in buccal, ophthalmic, intestinal, nasal, vaginal and rectal applications.

· Thickening at very low concentrations to produce a wide range of viscosities and flow properties in topical, lotions, creams and gels, oral suspensions and transdermal gel reservoirs.

· Permanent suspensions of insoluble ingredients in oral suspensions and topicals.

·  Emulsifying topical oil-in-water systems permanently, even at elevated
temperatures, with essentially no need for irritating surfactants.

Several properties of Carbopol make it potentially valuable as a pharmaceutical excipient .