Rheological properties of progesterone microemulsions: Influence of xanthan and chitosan biopolymer concentration

In this preformulations study, rheological properties of microemulsions with progesterone (1%) were studied to analyze the effect of xanthan and chitosan at different concentrations (0.5–3%). Steady shear and oscillatory rheological properties were analyzed using a controlled stress rheometer. Steady shear data were satisfactorily adjusted to the Carreau model. For all preparations, shear-thinning behavior was observed. Zero shear viscosity (η0) increased with the biopolymer concentration. The results from dynamic experiments showed the behavior of all preparations with xanthan gum and those of chitosan to be characteristic of weak gels and liquid-like solutions, respectively. The correlati…