A thermo- and photo stable composition comprising a chitosan/xanthan hydrogel
including
at least one thermo- or photo-sensitive substance chosen among the following: vitamins,
amino-acids, nucleic acids, and polypeptides. The hydrogel can be adapted to release
the thermo- or photo-sensible substances in either a human or an animal. The present
invention also discloses a method of making these hydrogel composition. Additionally,
the present invention presents a method of using these hydrogel composition in
dermatology or as a food supplement.