Abstract: Six kinds of collagen peptide with different molecular weights (<1 kDa and 1~3 kDa) were prepared separately by enzymolysis method with collagen obtained from jellyfish,bovine bone and cod skin as starting materials.Effects of time,molecular weight and mass concentration on the transdermal absorption performance of the peptides were examined by transdermal diffusion testing apparatus.Permeation processes of FITC-labeled collagen peptides through mouse skin were observed by fluorescence microscopy.Results showed that,when mass concentration of the six kinds of collagen peptide is 10 g/L,the order (from big to small) of capacity of transdermal absorption at 24 h is as follows:<1 kDa cod skin collagen peptide,<1 kDa bovine bone collagen peptide,<1 kDa jellyfish collagen peptide,1~3 kDa jellyfish collagen peptide,1~3 kDa bovine bone collagen peptide and 1~3 kDa cod skin collagen peptide.The transdermal absorption capacity of <1 kDa collagen peptide is better than that of 1~3 kDa collagen peptide.For collagen peptide from bovine bone and jellyfish,the increase of mass concentration will result in enhancing transdermal absorptivity;while for cod skin collagen peptide,the situation is on the contrary.For all the three kinds of source of collagen,the cumulative penetration capacity of collagen peptides per unit area increases with time,while decreases with molecular weight.

Key words: additive of skin-care cosmetics, collagen peptide, molecular weight, transdermal absorptivity