Assessment of physical stability and antioxidant activity of polysiloxane polyalkyl polyether copolymer-based creams

The purpose of the present work was to investigate the changes on physical stability (color,creaming,liquefaction,ph,conductivity,centrifugation,viscosity and rheological parameters) by non-ionic surfactant polysiloxane polyalkyl polyether copolymer based creams following inclusion of plant extract containing phenolic compounds. the antioxidant activity of the plant extract alone and after addition in the cream was assessed using the stable free radical 1,1-diphenyl-2-picrylhydrazyl (dpph) assay. physical stability was assessed by submitting the creams to storage at 8c,25c,40c,and at 40c with 70 rh (relative humidity) for a period of two months. physical characteristics of polysiloxane polyalkyl polyether copolymer based creams,that is,color,creaming,liquefaction,centrifugation and ph were noted at various intervals for 2 months. the viscosities and rheological behavior of creams were determined using a rotational rheometer. data were analyzed by using brookfield software rheocalc version (2.6) with ipc paste and power law (pl) math models. cream with plant extract showed pseudo plastic behaviour with decreasing on viscosity. the acacia nilotica (an) extract alone and the cream containing this extract showed great antioxidant and free radical scavenging activities. power law and ipc analysis were found to fit all the rheograms.