Carbomer934 NEW

Carbomer 934 is a specific, high-molecular-weight synthetic polymer made from acrylic acid. It is a member of the carbomer family, which are widely used as primary rheology modifiers—meaning they are exceptional thickening, gelling, and suspending agents in water-based formulations.

Its key characteristic is its ability to absorb water and swell dramatically, forming a viscous gel or lotion-like consistency, even when used at relatively low concentrations (often less than 1%).

Key Properties and Characteristics

• Appearance: A fluffy, white, acidic powder.

  Function: Primarily a thickening and gelling agent.

  Mechanism: It works by a process called neutralization. In its raw form, Carbomer 934 is acidic and the chains are coiled. When a base (like sodium hydroxide, triethanolamine, or AMPD) is added, the polymer chains uncoil and ionize. These negatively charged chains repel each other, absorbing water and expanding, which creates a clear, viscous gel.

  Viscosity: It is known for producing very high viscosity and excellent clarity in gels.

  Suspension: It creates a stable, three-dimensional network that can suspend solid particles (like drug crystals or pigments) and prevent oil droplets from coalescing.

Common Uses and Applications

Carbomer 934 is a workhorse ingredient in the pharmaceutical and, to a lesser extent nowadays, the cosmetic industry.

1. Pharmaceuticals (Primary Use)

This is the most significant application for Carbomer 934, especially in sterile products meant for the eye or for injection.

• Ophthalmic Gels: Used in eye drops (e.g., for dry eyes or to deliver medication) because it provides prolonged contact time on the eye surface. Its high purity and specific molecular weight make it suitable for this sensitive area.

  Topical Gels: Used as a base for medicated gels applied to the skin (e.g., for pain relief, acne treatment, or corticosteroid delivery).

  Controlled-Release Drug Delivery: Its gel structure can be used to control the release rate of an active drug ingredient.

2. Personal Care and Cosmetics

While other carbomers (like 940, 980, 981) are more common in modern cosmetics, Carbomer 934 can be found in:

• Gels: Such as aloe vera gels, hair gels, and hand sanitizing gels.

  Creams and Lotions: To provide a rich, stable texture.

  Toothpaste: As a thickener to give it the desired consistency.

Carbomer 934 vs. Other Carbomers

It's important to distinguish Carbomer 934 from its cousins (like Carbomer 940, 941, 980, 981, etc.). The numbers indicate slight differences in the manufacturing process and molecular structure, which lead to different performance characteristics:

The Critical Difference: The Benzene Issue

• Carbomer 934 was historically polymerized using benzene as a solvent. Benzene is a known human carcinogen.

  While the final polymer is extensively purified, regulatory bodies like the US FDA have expressed concerns about potential trace residues.

  As a result, Carbomer 934 is no longer the first choice for new cosmetic formulations. It has been largely replaced by "benzene-free" carbomers like Carbomer 974P, 980, 981, ETD 2020, etc., which use safer solvents like ethyl acetate or cyclohexane.

Safety and Regulation

• Safety: Carbomer 934 is generally considered non-toxic and non-irritating when used in approved concentrations. Its safety profile is well-established for topical and ophthalmic use.

  Regulation: It is approved for use globally. It is listed in major pharmacopoeias like the United States Pharmacopeia (USP) and is generally recognized as safe for its intended uses. However, due to the benzene synthesis issue mentioned above, its use is more restricted to established pharmaceutical applications where its specific performance is critical.

Summary

In short, Carbomer 934 is a highly effective and classic gelling agent, prized in the pharmaceutical industry for its ability to create clear, high-viscosity gels, especially for sensitive applications like eye drops. Its legacy is tempered by its manufacturing process, which has led to the development of safer, modern alternatives.