Assessment of physical stability and photoprotective activity of topical formulations added with calendula oil

In the present work, the changes on physical properties (pH, viscosity, flow index and tixotropy) of topical formulations were evaluated following addition of calendula oil containing flavonoids. Also the photoprotective effect of these topical formulations were evaluated against ultra violet rays (UVR) induced sunburn in terms of sun protection factor (SPF). Formulation added with sun flower oil was used to compare the physical stability and photoprotective activity. Formulations added with calendula oil exhibited an average pH 7. 2 and pseudoplastic behavior. The tixotropy values for formulations F3 and F4, after addition with calendula oil were found to be statistically decreased when compared with FS and Fb. The rheological parameters were constant during the study and the rheograms exhibited no sign of instability when studied at 4°, 27° and 40°C on different days of storage. The F3 and F4 samples showed statistically higher SPF (14 and 15 respectively) when compared with Fb (without active sunscreening agent). The highest SPF value 16 was recorded for FS (control formulation added with sun flower oil) while Fb showed lowest SPF vale 5. We concluded that F3, F4 and FS showed higher SPF and physical stability. This study of physical stability and photoprotectice activity of topical formulation can help in the development of sunscreen formulation. © 2012 Institute of Oriental Medicine, Kyung Hee University.