Since their creation as the first commercial carbomers over 50 years ago, Lubrizol’s Carbopol® polymers have continued to be the highest quality carbomers on the market. Utilized in pharmaceutical products as rheology modifiers, tablet binders, suspension stabilizers, extended release polymers, mucoadhesive aids, and bioavailability enhancers, Carbopol polymers are well known for their versatility and ease of use as pharmaceutical excipients. Products within the Carbopol polymer family are chemically similar in that they are all high molecular weight, crosslinked polyacrylic acid polymers. However, these gel forming polymers differ by their chemical crosslinking and can be grouped into the following categories.
- Carbopol homopolymers: acrylic acid crosslinked with allyl sucrose or allyl pentaerythritol
- Carbopol copolymers: acrylic acid and C10-C30 alkyl acrylate crosslinked with allyl pentaerythritol
- Carbopol interpolymers: carbomer homopolymer or copolymer that contains a block copolymer of polyethylene glycol and a long chain alkyl acid ester
We have made numerous enhancements to the Carbopol polymer family over time to help address regulatory demands, increase product robustness, and improve product handling, including, when mixing or processing Carbopol, ease of polymer dispersion to cut down on processing time. As part of these enhancements, our polyacrylic acid polymers are synthesized to meet the highest standards of safety. “Traditional” carbomers are synthesized in benzene, a substance that is increasingly restricted for use in pharmaceutical excipient applications. Our “toxicologically preferred” carbomers are synthesized in either ethyl acetate or a cosolvent mixture of ethyl acetate and cyclohexane, which are the products we now recommend for all new drug development projects.
In addition to our traditional excipients, LLS Health has added newer innovations to the Carbopol family in recent years, such as:
- Carbopol Ultrez polymers provide self-wetting capabilities for polymer dispersion that does not require mixing, enabling greater ease of use in formulating and processing.
- Carbopol 71G NF is the only granular carbomer available for direct compression formulations, providing increased versatility in the manufacture of oral solid dose products
- Carbopol ETD 2020 NF is designed to provide increased electrolyte tolerance in drug formulations.
Product Overview and Recommendations
| Carbopol Polymer | Polymerization Solvent | Carbomer Product Type | Viscosity, cP (0.5 wt% at pH 7.5) |
| 71G NF | Ethyl Acetate | Homopolymer | 4,000 - 11,000 |
| 971P NF | Ethyl Acetate | Homopolymer | 4,000 - 11,000 |
| 974P NF | Ethyl Acetate | Homopolymer | 29,400 - 39,400 |
| 980 NF | Cosolvent1 | Homopolymer | 40,000 - 60,000 |
| 981 NF | Cosolvent1 | Homopolymer | 4,000 - 10,000 |
| 5984 EP | Cosolvent1 | Homopolymer | 30,500 - 39,400 |
| ETD 2020 NF | Cosolvent1 | Interpolymer | 47,000 - 77,0002 |
| Ultrez 10 NF | Cosolvent1 | Interpolymer | 45,000 - 65,000 |
| 934 NF | Benzene | Homopolymer | 30,500 - 39,400 |
| 934P NF | Benzene | Homopolymer | 29,400 - 39,400 |
| 940 NF | Benzene | Homopolymer | 40,000 - 60,000 |
| 941 NF | Benzene | Homopolymer | 4,000 - 10,000 |
| 1342 NF | Benzene | Copolymer | 9,500 - 26,5002 |
|
1 Cosolvent system made using cyclohexane and ethyl acetate
|
|||
Carbopol Products for Oral Pharmaceutical Applications
| Carbopol Polymer | Suspensions | Bioadhesive Formulations | Roller-Compaction | Solid Dosage Wet Granulation |
Direct Compression |
|---|---|---|---|---|---|
| 71G NF | ✓ | ✓ | ✓ | ✓ | |
| 971P NF | ✓ | ✓ | ✓ | ✓ | |
| 974P NF | ✓ | ✓ | ✓ | ✓ | |
| 934P NF | ✓ | ✓ | ✓ | ✓ |
Carbopol and Pemulen™ Polymers for Topical Applications
| Comparison Overview of Carbopol and Pemulen Polymers for Topical Applications | ||||||
|---|---|---|---|---|---|---|
| Self Wetting Polymers | Ultrez 10 NF | |||||
| Ethyl Acetate Polymers | 974P NF | 971P NF | ||||
| Cosolvent Polymers | 5984 EP | 980 NF | 981 NF | TR-1 NF, TR-2 NF 1, ETD 2020 NF |
||
| Traditional Polymers2 | 934 NF, 934P NF |
940 NF | 941 NF | 1342 NF | ||
| Properties in a Formulated Application | ||||||
| Flow Characteristics | Short | Short | Short | Very Short | Long | Long |
| Relative Viscosity | High | High | High | Very High | Low | Medium |
| Suspending Ability (yield value) |
High | High | High | High | High | High |
| Mucilage Clarity | High | Medium | Medium | High | High | High |
| Relative Ion Tolerance | Low | Low | Low | Low | Medium | High |
| Relative Shear Tolerance3 | Medium | Medium | High | High | Low | Low |
| Applications | ||||||
| Clear Gels | ✓ | ✓ | ✓ | ✓ | ✓ | |
| Hydroalcoholic Gels | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Lotions | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Creams | ✓ | ✓ | ✓ | ✓ | ||
| Surfactants Systems | ✓ | |||||
| High Electrolyte Systems | ✓ | |||||
1 Pemulen Polymers (Pemulen TR-1 NF and TR-2 NF). All other products noted in the table belong to the Carbopol polymer product family.
2 Traditional polymers are synthesized in benzene. The Carbomers Monograph in the European Pharmacopeia stipulates that benzene is limited to 2 ppm.
3 Prolonged exposure to high shear should be avoided for all carbomers.
Additionally, it may be desirable to substitute a benzene polymerized carbomer with a non-benzene polymerized carbomer in a pharmaceutical formulation. The following table shows recommended substitutes for the benzene grade Carbopol products based on viscosity criteria. The substitute products are polymerized in either ethyl acetate or a cosolvent mixture of ethyl acetate and cyclohexane. If a substitution is made in a pharmaceutical formulation, it is recommended that key performance properties be ascertained and regulatory considerations be taken into account. Depending on the desired dosage requirements, other Carbopol polymers may be suitable alternatives.
| Benzene Grade Carbopol Polymer | Recommended Non-Benzene Carbopol or Pemulen Polymers |
| Carbopol® 934 NF polymer | Carbopol® 974P NF polymer and Carbopol® 5984 EP polymer |
| Carbopol® 934P NF polymer | Carbopol® 974P NF polymer and Carbopol® 5984 EP polymer |
| Carbopol® 940 NF polymer | Carbopol® 980 NF polymer |
| Carbopol® 941 NF polymer | Carbopol® 971P NF polymer and Carbopol® 981 NF polymer |
| Carbopol® 1342 NF polymer | Pemulen™ TR-1 NF polymer |