title: Use of sorption promoters to increase systemic absorption of coumarin from transdermal drug delivery systems.
abstract: In previous communications it was shown that coumarin is transdermally well absorbed. Increasing the application area for a coumarin ointment from 5 cm2 to 30 cm2, the absolute bioavailability increases from 8.6% to 66%. Using a transdermal drug delivery system (TDDS) based on an elastomer matrix, the absolute bioavailability was 21.9%. By selecting a proper sorption promoter (Labrafil), the absolute bioavailability increased to 71%. No correlation was found between tlag, flux or amount permeated obtained from ex vivo flux measurements, and the in vivo parameters Cmax and AUC. Whereas the bioavailability of a large area application of coumarin ointment is practically the same as with a small TDDS, the latter one is preferred to maintain a therapeutic concentration over a 24 h or 48 h period.
authors.affiliation: Division of Pharmaceutics and Drug Delivery Systems, University of Cincinnati Medical Center, OH.
authors.forename: W A
authors.initials: WA
authors.lastname: Ritschel
authors.forename: J K
authors.initials: JK
authors.lastname: Barkhaus
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D001682:Biological Availability; D003374:Coumarins / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004058:Diffusion; D004339:Drug Compounding; D066298:In Vitro Techniques; D051381:Rats; D011919:Rats, Inbred Strains; D012869:Skin Absorption; D012995:Solubility
chemical_list: D003374:Coumarins