Influence of quaternary ammonium salts on the topical hydroxyproline bioavailabilityJacek Arct 1/, Anna Wóltańska 2/, Katarzyna Pytkowska 3/, Magdalena Krulikowska 4/ 1/ Dr Seidel´s Foundation, Warsaw 2/ Faculty of Chemistry, Warsaw University of Technology 3/ Maria Skłodowska-Curie Medical Academy in Warsaw 4/ Henkel Poland Summary Introduction. Quaternary ammonium salts are known promoters of the permeation through the formation of lipophilic ion pairs. In pharmacy, they are often used for topical drug administration. However, the literature does not provide information on cosmetic applications, especially concerning compounds that can form zwitterions. Aim. The rate of permeation of hydroxyproline through the human epidermal modelling membrane was studied Materials and methods. Commercial hydroxyproline and quternary ammonium salts were used. Permeation measre were prowided with typical synthetic membrane mimicking stratum corneum Results. Both mono- and polymeric lipophilic ammonium salts were found to inhibit permeation. Based on the relationship between the degree of inhibition and the physicochemical properties of the salt, a concept of the mechanism of this phenomenon was put forward, which was confirmed experimentally. Conclusions. The obtained results indicate the need to caution when introducing mono- and polymeric ammonium salts into cosmetic products. Key words: hydroxyproline, ammonium salts, permeation promoter |