Topical Delivery of Retinyl Ascorbate Co-Drug

Abstract

Retinyl ascorbate (RA-AsA), an ester co-drug of vitamins A (RA) and C (AsA), is proposed as a topical antioxidant/cell division regulator for reducing UV-induced generation of free radicals and disrupted dermal cell growth. The efficacy of dermatological agents is influenced by their retention within the skin, which is increased by the interaction with skin components. Keratin is the major protein (∼95%) in the skin, and this paper reports the binding of RA-AsA, RA, AsA, retinol, ascorbic acid palmitate and retinol palmitate to three tissues – human callus, pig ear skin and bovine horn keratin. Tissue samples were incubated with solutions of compounds and the uptake measured as the ratio of bound/free compound at equilibrium. Binding to keratin was assessed using delipidised tissue, and was much higher for the polar compounds, suggesting dipolar/H-bonding interaction. Binding strength was ranked as human > porcine > bovine, but there was no distinction for highly lipophilic compounds. The binding characteristic of native tissues was complicated by lipid content of the tissues. There seemed to be a dual effect. The binding of very lipophilic materials increased with lipid content, implying that a substantial amount is dissolved in the lipid matrix. For highly polar AsA, lipid content decreased the binding, suggesting that the lipid reduced the strong polar interactions with skin protein/keratin.

Metabolism of captopril carboxyl ester derivatives for percutaneous absorption

“…They suggested that porcine skin is a good model for human skin in investigating the metabolism and pharmacokinetics of ester prodrugs. The findings of this work are supported by other studies such as Abdulmajed et al 14 and Suppasansatorn et al 15 Further, Prusakiewicz et al 16 examined a range of skin from different species. They found that metabolism and kinetics of hydrolysis in the minipig was also comparable with human skin, whereas metabolic activity in the rat was significantly higher by two or three orders of magnitude.…”

The Role of Corneocytes in Skin Transport Revised—A Combined Computational and Experimental Approach

“…Furthermore, partition coefficients into delipidized SC and callus shavings have been proposed as a model to investigate compound binding to corneocyte proteins (37,42,52). There are several shortcomings of these methods.…”

Formation of a protection film on the human skin by microparticles

“…5). Therefore, it can be assumed that the barrier cream firmly adheres to the skin surface and also protects the furrows, wrinkles and the openings of the hair follicles and sweat glands, which have to be considered as efficient reservoirs for the sweat and consequently for the chemotherapeutics reaching the skin surface via the sweat [31][32][33].…”