Carbomer

Synonyms: Acrypol; Acritamer; acrylic acid polymer; carbomera; Carbopol; carboxy polymethylene; polyacrylic acid; carboxyvinyl polymer; Pemulen; Tego Carbomer.

Description: Carbomers are white-colored, ‘fluffy’, acidic, hygroscopic powders
with a characteristic slight odor. A granular carbomer is also available (Carbopol 71G)

Chemical Name: Carbomer

Bioadhesive material; controlled-release agent; emulsifying agent;
emulsion stabilizer; rheology modifier; stabilizing agent; suspending
agent; tablet binder.

• Carbomers are used in liquid or semisolid pharmaceutical formulations as rheology modifiers.

• Formulations include creams, gels, lotions and ointments for use in ophthalmic, rectal, topical and vaginal preparations.

• However, carbomer having low residuals of other solvents than the ICH-defined ‘Class I OVI solvents’ may be used in Europe.

• Carbomer having low residuals of ethyl acetate, such as Carbopol 971P NF or Carbopol 974P NF, may be used in oral preparations, in suspensions, capsules or tablets.(23–35) In tablet formulations, carbomers are used as controlled release agents and/or as binders. In contrast to linear polymers, higher viscosity does not result in slower drug release with carbomers.

• Lightly crosslinked carbomers (lower viscosity) are generally more efficient in controlling drug release than highly crosslinked carbomers (higher viscosity).

• In wet granulation processes, water, solvents or their mixtures can be used as the granulating fluid.

• The tackiness of the wet mass may be reduced by including talc in the formulation or by adding certain cationic species to the granulating fluid.

Carbomers are discolored by resorcinol and are incompatible with phenol, cationic polymers, strong acids, and high levels of electrolytes. Certain antimicrobial adjuvants should also be avoided or used at low levels. Trace levels of iron and other transition metals can catalytically degrade carbomer dispersions.

Carbomers are used extensively in nonparenteral products, particularly topical liquid and semisolid preparations. Grades polymerized in ethyl acetate may also be used in oral formulations

Observe normal precautions appropriate to the circumstances and quantity of material handled. Excessive dust generation should be minimized to avoid the risk of explosion (lowest explosive concentration is 130 g/m3 ). Carbomer dust is irritating to the eyes, mucous membranes, and respiratory tract. In the event of eye contact with carbomer dust, saline should be used for irrigation purposes. Gloves, eye protecti

Polycarbophil