title: Absorption of sunscreens and other compounds through human skin in vivo: derivation of a method to predict maximum fluxes.
abstract: OBJECTIVE
  The goal of this study was to quantify the transdermally absorbed amounts of the sunscreens octyl dimethyl p-aminobenzoic acid, oxybenzone, 4-isopropyl-dibenzoylmethane, 3-(4-methylbenzylidene)-camphor, isoamyl-4-methoxycinnamate, the repellent and plasticizer dibutyl phthalate, the antioxidant 3.5-di-t-butyl-4-hydroxyanisol, and the antimicrobial compounds butyl-4-hydroxybenzoate, biphenyl-2-ol, and 2,4,4'-tri-chlor-2'-hydroxydiphenylether (triclosane). Permeabilities PB and maximum fluxes Jmax should be correlated with relevant physicochemical properties.
  
  
  METHODS
  Saturated solutions of the above-mentioned compounds in a propylene glycol/water mixture were applied to the skin using glass chambers which were fixed to the upper arms of volunteers. Maximum fluxes were calculated from concentration decreases in the vehicle.
  
  
  RESULTS
  A linear relationship between the logarithms of permeabilities PB of the penetrants (0.02-0.28 cm h-1) and the corresponding octanol/vehicle partition coefficients PCOct/V (166-186,208) was found. Consequently, the influence of aqueous boundary layers could be neglected. However, the slope of the resulting straight line of 0.38 is considerably smaller than unity indicating that PCOct/V does not represent the lipophilicity of the stratum corneum adequately. Maximum fluxes range from 0.5 to 130 micrograms cm-2 h-1. A general equation for the calculation of Jmax was derived based on experimental data taking into account the PCOct/V and the solubilities CsV of the respective penetrants in the vehicle.
authors.affiliation: Dept. of Pharmaceutical Technology, Heinrich Heine University, Düsseldorf, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Hagedorn-Leweke
authors.forename: B C
authors.initials: BC
authors.lastname: Lippold
mesh_terms: D000279:Administration, Cutaneous; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D000975:Antioxidants / Q000008:administration & dosage / Q000493:pharmacokinetics; D001693:Biological Transport, Active; D002083:Butylated Hydroxyanisole / Q000008:administration & dosage / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid; D003879:Dermatologic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D003993:Dibutyl Phthalate / Q000008:administration & dosage / Q000493:pharmacokinetics; D006801:Humans; D008954:Models, Biological; D010968:Plasticizers / Q000008:administration & dosage / Q000493:pharmacokinetics; D012869:Skin Absorption / Q000502:physiology*; D012995:Solubility; D013473:Sunscreening Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D000890:Anti-Infective Agents; D000975:Antioxidants; D003879:Dermatologic Agents; D010968:Plasticizers; D013473:Sunscreening Agents; D003993:Dibutyl Phthalate; D002083:Butylated Hydroxyanisole