Interpretation and prediction of the kinetics of transdermal drug delivery: oestradiol, hyoscine and timolol.
Int J Pharm 1986 Oct; 32(2-3):159-163
A kinetic model for the prediction of the plasma concentration of topically administered drugs was described for estradiol, hyoscine, and timolol. The model was based on the physiochemical determination of the rate constants for the drugs between the transdermal device and the stratum corneum, the stratum corneum and viable tissue, the tissue capillary interface, and the excretion rate from blood to urine. Factors affecting the kinetics included competition for the drug at the device stratum corneum interface, the drug molecular weight, drug partition coefficients, and drug biological half life. The predictive equations were applied to estradiol, hyoscine, and timolol using physiochemical and pharmacokinetic data obtained from the published literature, the surface areas of the transdermal devices used as the delivery system, and the in-vitro release characteristics of the drugs in either the patch adhesive or the topical vehicle used for administration of the therapeutic agent. The kinetic simulations were compared to published human in-vivo data with good agreement. The authors conclude that the kinetic model can be used to determine the feasibility of transdermal drug delivery for different compounds.
NIOSH-Publication; NIOSH-Grant; Dermatitis; Biokinetics; Pharmacodynamics; Analytical-models; Medical-treatment; Skin-absorption; Drug-therapy
Pharmacy University of California 926 Medical Sciences Building San Francisco, Calif 94143
International Journal of Pharmaceutics
University of California San Francisco, San Francisco, California