Carbomer Carbopol products are used extensively as thickeners in cosmetics and pharmaceutical products to improve their rheological properties. The cross-linked thickeners can form a networked microgel structure in solutions and are very useful as platforms in drug delivery applications because controlled release of medicaments is possible. Carbomer carbopol products have a potential wide range of applicability in the pharmaceutical and dermo cosmetic fields.

We, Anhui nemwan fine chemicals co.,ltd, as a leading manufacturer of carbomer products,  have been improving and launching carbomer products. Our own experienced R&D team study the rheological behavior of carbomer (Carbopol) gels in the pH range 5.0–8.0. The specific objectives are outlined below. First: To measure the linear viscoelastic properties such as elastic modulus and zero shear viscosity of the carbomer (Carbopol) gels in the cosolvent system. Second: To estimate yield strengths of the materials in terms of stress and strain using a variety of techniques. Third: To construct flow curves for a range of temperatures and to model the temperature dependence of the viscosity. Fourth: To determine whether these topical gels exhibit thixotropy.

 Conclusion:  

All the Carbomer carbopol） gel samples show viscoelasticity. In general, the viscoelasticity increases with increasing pH but the change is not significant. The topical gels exhibit remarkable temperature stability. Flow curves obtained at different temperatures indicate carbomer (Carbopol) microgels show significant pseudoplastic behavior. Several rheological techniques confirm that substantial amounts of stress greater than the yield values of the topical gels are required before the topical gels can start to flow. The pharmaceutical gel samples exhibit thixotropy but only at higher deformation rates. However, the amount of thixotropy is not significant, suggesting stability of gels at high shear rates comparable to those experienced in physiological processes when gels are applied over skin. The viscoelastic nature of Carbomer Carbopol dispersions with substantial yield strength suggests that such aqueous gels may be useful as topical and mucoadhesive delivery systems. The long relaxation time, remarkable temperature stability, and low thixotropy of the gels make them amenable in delivery systems requiring prolonged drug residence time with enhanced absorption at the application areas. The rheological parameters can be used along with other studies such as bioavailability and residence time of drugs to construct a framework for designing optimal drug delivery systems.