title: Effect of collagen microparticles on the stability of retinol and its absorption into hairless mouse skin in vitro.
abstract: Collagen microparticles (CMPs) were manufactured with the objective to enhance the dermal delivery of all-trans retinol. The influence of CMPs on the stability of retinol was investigated after a long-term storage of two hydrogel preparations (hydroxyethylcellulose). The retinol in the first preparation was adsorbed onto the surface of CMPs, whereas the retinol in the second preparation was freshly precipitated. Retinol was not protected from oxidization by adsorption to CMPs. However, the sorption on the surface of CMPs prevented the retinol from crystallization. On the other hand, significant crystallization occurred with the freshly precipitated retinol. For the study of the in vitro penetration of retinol into hairless mouse skin three preparations for topical application were used. Beside the two hydrogel preparations mentioned above, an O/W-creme was tested. The study of the in vitro penetration was performed by using Franz diffusion cells and tritium labelled retinol. Both hydrogel preparations yielded significantly higher quantities of penetrated retinol than the O/W-creme. The amounts of radioactive retinol in the stratum corneum and in the epidermis and dermis were in all cases more than ten times higher for the hydrogel preparations. The other remarkable result was that the presence of CMPs led to a faster and higher transport of retinol into the skin than the freshly precipitated drug. With the CMP preparation a statistically significant increase of penetrated retinol was found during the first 4 h after application in the stratum corneum. In the residual epidermis and dermis a clear tendency towards enhanced quantities of penetrated retinol also were observed with the CMPs compared to the freshly precipitated drug in the hydrogel.
authors.affiliation: Institut für Pharmazeutische Technologie, Universität Frankfurt/Main.
authors.forename: B
authors.initials: B
authors.lastname: Rössler
authors.forename: J
authors.initials: J
authors.lastname: Kreuter
authors.forename: G
authors.initials: G
authors.lastname: Ross
mesh_terms: D000818:Animals; D002482:Cellulose / Q000031:analogs & derivatives; D003094:Collagen / Q000737:chemistry* / Q000494:pharmacology*; D003460:Crystallization; D004355:Drug Stability; D004356:Drug Storage; D005260:Female; D066298:In Vitro Techniques; D051379:Mice; D008812:Mice, Hairless; D008809:Mice, Inbred C3H; D008863:Microspheres; D010316:Particle Size; D012869:Skin Absorption / Q000187:drug effects*; D013696:Temperature; D014801:Vitamin A / Q000737:chemistry* / Q000493:pharmacokinetics*
chemical_list: D014801:Vitamin A; D002482:Cellulose; C002283:hydroxyethylcellulose; D003094:Collagen