It is concluded that the results in the present study validate
chromatographical and rheological methods for analysis
of gel-cream stability. Rheology measurements are simple and
effective means to compare properties over time and HPLC furnishes
accurate quantitative data on different substances added
to complex matrixes. In addition, the results contribute to the
understanding of cosmetic stability in formulations containing
retinyl palmitate and tocopheryl acetate and confirm that chemical
and physical stability must be evaluated at the same time
since they seem to have related effects.