| pubmed-article:3245850 | pubmed:abstractText | 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. | lld:pubmed |
