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Benzene
Ethyl Acetate
Cosolvent1
Homopolymer
Copolymer
Interpolymer
Viscosity, cP (0.5 wt% at pH 7.5)
1 Cosolvent system made using cyclohexane and ethyl acetate 2 1.0 wt%
Due to regulatory restrictions on the use of benzene in pharmaceutical formulations, Lubrizol recommends that carbomers polymerized in either ethyl acetate or a cosolvent mixture of ethyl acetate and cyclohexane be used for all new drug development projects.
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.