Lakhasly

Turowski and Adelmann-Grill (79), extensively studied the influence of peptide mo?lecular weight and hair/skin substantivity and found results that openly contrast with those reported by others (9,10,93).The main findings were the following: (1) dependence of the substan?tivity on the peptide concentration in the medium was almost linear and saturation was not attained at a concentration below 5%; (2) the amount of protein sorbed to the hair varied significantly with the washing conditions (amount of water used and rinse duration), especially when applied in shampoos; (3) the characteristics of the shampoo formulations strongly influenced both substantivity and permanence of the peptides on the hair after washing; (4) absorption of peptides on damaged hair was higher than on untreated hair when at low concentration in the medium and for short incubation time;

Turowski and Adelmann-Grill (79), extensively studied the influence of peptide mo￾lecular weight and hair/skin substantivity and found results that openly contrast with those
reported by others (9,10,93). In this work substantivity of collagen hydrolysates was tested
in water solutions and tenside preparations under conditions resembling actual cosmetic
application. Hair substantivity was evaluated on virgin and bleached/dyed hair by labeling
peptides with 125iodine and measuring radioactivity of the substrate after suitable treatment.
Great care was given to radiolabeling procedures of peptides in this work, and the authors
excluded the possibility that higher- or lower-molecular-mass fractions had preferentially
been taken up by the radioactive label. Collagen hydrolysates were characterized for
average isoelectric point and molecular weight distribution. In addition to the chemical
characteristics of the tested hydrolysates, other variables investigated were: hydrolysate
concentration in the application medium, time of incubation, type of hair (untreated and
bleached/dyed), type of the vehicle (water, shampoos with different tenside composition),
washing conditions. The main findings were the following: (1) dependence of the substan￾tivity on the peptide concentration in the medium was almost linear and saturation was
not attained at a concentration below 5%; (2) the amount of protein sorbed to the hair
varied significantly with the washing conditions (amount of water used and rinse duration),
especially when applied in shampoos; (3) the characteristics of the shampoo formulations
strongly influenced both substantivity and permanence of the peptides on the hair after
washing; (4) absorption of peptides on damaged hair was higher than on untreated hair
when at low concentration in the medium and for short incubation time;