title: Kinetic model to predict the absorption of nasally applied drugs from in vitro transcellular permeability of drugs.
abstract: The purpose of this study is to propose a kinetic model to predict the absorption of nasally applied drugs from their permeability to the Caco-2 monolayer (P(Caco-2)). Since a drug applied to the nose in an in vivo physiologic condition is translocated to the gastrointestinal (GI) tract by coordinated beats of cilia (mucociliary clearance, MC), the drug undergoes absorption both from the nasal cavity and from the GI tract. The detailed MC of the rat was examined, using inulin as a marker of the applied solution. Inulin disappeared monoexponentially from the nasal cavity, indicating that the MC can be assumed to follow first-order kinetics. From the disappearance of inulin, the first order rate constant for MC (k(MC)) was calculated as 0.0145 min(-1). In the proposed kinetic model, the fractional absorption of the drug following nasal application is predicted as the sum of F(NC) (fractional absorption from the nasal cavity) and F(GI) (fractional absorption from the GI tract), both of which are estimated indirectly from P(Caco-2). F(NC) is calculated according to the equation, k(a)/(k(a)+k(MC)), where k(a) is the absorption rate constant. Nasal drug absorption is assumed to follow first order kinetics. The k(a) of four drugs was initially calculated from k(MC) and their F(NC); thereafter, the linear relationship between k(a) and P(Caco-2), from which k(a) is predicted, was determined. F(GI) is calculated as F(p.o.)(1-F(NC)), where F(p.o.) is fractional absorption after oral administration. F(p.o.) was predicted from the previously determined sigmoid curve between F(p.o.) and P(Caco-2). The proposed kinetic model is the first estimation system for nasal drug absorption based on drug disposition after nasal application and is useful for the development of nasal dosage forms.
authors.affiliation: School of Pharmacy, Shujitsu University, Okayama, Japan. t-furu@shujitsu.ac.jp
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Furubayashi
authors.forename: Akiko
authors.initials: A
authors.lastname: Kamaguchi
authors.forename: Kazushi
authors.initials: K
authors.lastname: Kawaharada
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Masaoka
authors.forename: Makoto
authors.initials: M
authors.lastname: Kataoka
authors.forename: Shinji
authors.initials: S
authors.lastname: Yamashita
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Higashi
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Sakane
mesh_terms: D000042:Absorption; D000281:Administration, Intranasal; D000818:Animals; D018938:Caco-2 Cells; D002463:Cell Membrane Permeability / Q000187:drug effects*; D006801:Humans; D007444:Inulin / Q000008:administration & dosage / Q000493:pharmacokinetics; D008297:Male; D008954:Models, Biological; D009297:Nasal Mucosa / Q000378:metabolism*; D004364:Pharmaceutical Preparations / Q000008:administration & dosage*; D010599:Pharmacokinetics; D011237:Predictive Value of Tests; D051381:Rats; D017208:Rats, Wistar
chemical_list: D004364:Pharmaceutical Preparations; D007444:Inulin