Rheological behavior and microbiological studies of Carbopol® hydrogels

Rheological and microbiological studies were performed for hydrogels prepared with different types of crosslinked polyacrylate polymers (Carbopol® 940, 980 and Ultrez® 10). All hydrogels exhibited typical viscoelastic properties, with no Newtonian flow regimen. Linearizing viscosity profiles, excellent correlations were obtained between logarithmic values of viscosity and shear rate. The study also revealed that Carbopol® 980 and Ultrez® 10 based hydrogels showed higher viscosity than the Carbopol® 940 based. Microbiological studies were performed in order to find a suitable preservative for the prepared hydrogels. Both the diffusion based method and challenge test indicated that phenylmercuric borate was the most effective preservative, regardless of the microorganism tested and can be suitable for preventing antimicrobial growth in the prepared hydrogels. Keywords: Carbopol®, hydrogel, pseudoplastic, challenge test