title: Carrageenans can regulate the pulmonary absorption of antiasthmatic drugs and their retention in the rat lung tissues without any membrane damage.
abstract: Effects of various viscous vehicles on pulmonary absorption of antiasthmatic drugs were examined by an in situ pulmonary absorption experiment. Theophylline and fluticasone propionate were used as antiasthmatic drugs. The serum concentration-time profile of theophylline without viscous vehicles was similar to that following the intravenous injection, indicating that pulmonary absorption of theophylline was rapid and absolute. The serum concentration of theophylline was not controlled in the presence of 5% gelatin or 2% sodium alginate. However, 1% iota-carrageenan could control and regulate the serum concentration of theophylline. In the pharmacokinetic analysis, the C(max) values of theophylline significantly decreased, and its T(max) values increased in the presence of 1% and 2% iota-carrageenan, 1% kappa-carrageenan, and 2% sodium alginate compared with the control. The MRT and MAT values of theophylline with 1% iota-carrageenan were significantly higher than those without viscous vehicles. The local concentration of theophylline in the lung at 1h after intratracheal administration increased five-fold with 1% iota-carrageenan compared with the control. On the other hand, the pulmonary absorption of fluticasone propionate was controlled and regulated in the presence of 0.5% kappa-carrageenan. Additionally, the pulmonary inflammation after the exposure of carrageenans administered to the lung was evaluated in rats. Iota- and kappa-carrageenans did not cause local serious damage and inflammation to the pulmonary tissue. Therefore, these findings indicated that the carrageenans were effective to regulate the absorption rate of antiasthmatic drugs including theophylline and fluticasone propionate.
authors.affiliation: Department of Biopharmaceutics, Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan. yamamoto@bm.kyoto-phu.ac.jp
authors.forename: Keigo
authors.initials: K
authors.lastname: Yamada
authors.forename: Naoki
authors.initials: N
authors.lastname: Kamada
authors.forename: Masaaki
authors.initials: M
authors.lastname: Odomi
authors.forename: Naoki
authors.initials: N
authors.lastname: Okada
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nabe
authors.forename: Takuya
authors.initials: T
authors.lastname: Fujita
authors.forename: Shigekatsu
authors.initials: S
authors.lastname: Kohno
authors.forename: Akira
authors.initials: A
authors.lastname: Yamamoto
mesh_terms: D000042:Absorption / Q000187:drug effects / Q000502:physiology; D000818:Animals; D018927:Anti-Asthmatic Agents / Q000493:pharmacokinetics*; D002351:Carrageenan / Q000493:pharmacokinetics*; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D018927:Anti-Asthmatic Agents; D002351:Carrageenan