karbomeer

Karbomeer, more commonly known in English as carbomer, refers to a family of high molecular weight, crosslinked polyacrylic acid polymers used as thickening, suspending, and stabilizing agents in cosmetics, personal care products, and pharmaceutical formulations. The term karbomeer represents a transliteration variant encountered in some languages or contexts, but the substance is typically called carbomer in English.

Composition and production

Carbomers are produced by polymerizing acrylic acid and crosslinking the polymer chains with polyfunctional allyl ethers (such as allyl sucrose polyethers or allyl pentaerythritol ethers). The crosslinking creates a three-dimensional network that swells massively in water to form gels. Different grades (for example, Carbomer 940, 941, 934, 980) vary in particle size, viscosity, and thickening efficiency, allowing formulators to tailor rheology.

Properties and mechanism

In aqueous systems, carbomers absorb water and expand to form highly viscous gels. They are usually activated by neutralization with bases such as triethanolamine or sodium hydroxide, which causes ionization of carboxyl groups and a dramatic increase in viscosity. The gels are typically pseudoplastic and exhibit thixotropy, meaning viscosity decreases under shear and recovers when at rest. Carbomer performance is sensitive to pH, temperature, and ionic strength; high salt content can weaken thickening if the polymer is not properly neutralized.

Uses

Carbomers serve as primary thickeners in creams, gels, lotions, suspensions, and emulsions. They help stabilize suspensions, improve texture, and control flow. They are widely used in topical pharmaceuticals, ophthalmic solutions, and cosmetic formulations for viscosity control and stabilizing dispersed phases.

Safety and regulation

Carbomers are broadly regarded as safe for topical use at approved concentrations and are listed under the INCI name Carbomer in cosmetic and pharmaceutical ingredients. They are minimally absorbed and generally well tolerated, though irritation can occur at high concentrations or with sensitive individuals. Proper formulation and pH control are essential for optimal performance.