title: Transdermal absorption of L-dopa from hydrogel in rats.
abstract: To improve compliance in administration of l-dopa, transdermal absorption of the agent was investigated in rats in vitro employing two-chamber diffusion cells in which the excised rat abdominal skin was mounted, and in vivo using an alcoholic hydrogel containing l-menthol. The in vitro study revealed that in presence of l-menthol (2%, W/W), ethanol (20 and 40%, V/V) accelerated transdermal penetration of l-dopa with an increase of its percentages. The in vivo study showed that when the l-dopa-hydrogel containing 2% l-menthol and 40% ethanol was attached on the skin, plasma levels of l-dopa and norepinephrine increased with the time elapsed; the level of dopamine increased and reached a plateau thereafter; and the level of epinephrine was unchanged. These in vitro and in vivo findings indicated that the hydrogel formulation of l-dopa provides new direction in treating Parkinson's disease.
authors.affiliation: Department of Clinical Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-02, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Sudo
authors.forename: H
authors.initials: H
authors.lastname: Iwase
authors.forename: J
authors.initials: J
authors.lastname: Terui
authors.forename: K
authors.initials: K
authors.lastname: Kakuno
authors.forename: M
authors.initials: M
authors.lastname: Soyama
authors.forename: K
authors.initials: K
authors.lastname: Takayama
authors.forename: T
authors.initials: T
authors.lastname: Nagai
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D004298:Dopamine / Q000097:blood; D015259:Dopamine Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D004837:Epinephrine / Q000097:blood; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000008:administration & dosage / Q000493:pharmacokinetics*; D007275:Injections, Intravenous; D007980:Levodopa / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D012869:Skin Absorption
chemical_list: D015259:Dopamine Agents; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D007980:Levodopa; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine