title: Validation of excised bovine nasal mucosa as in vitro model to study drug transport and metabolic pathways in nasal epithelium.
abstract: The present work aims at the validation of excised bovine nasal mucosa as an in vitro model to address transport and metabolism pathways relative to the nasal mucosal uptake of therapeutic peptides. Preservation of the viability of the excised tissue in the course of in vitro studies of up to 3 h was demonstrated by (i) positive viability staining, (ii) constant transepithelial electrical resistance (42 +/- 12 Omega cm(2)), (iii) constant rates of metabolic turnover, and (iv) linear permeation profiles of therapeutic peptides and (3)H-mannitol. Using 1-leucine-4-methoxy-2-naphthylamide as a model substrate, we observed no difference between bovine and human nasal aminopeptidase activity. By a series of therapeutic peptides, no direct correlation was found between their effective permeability coefficients (from 0. 1 x 10(-5) to 5 x 10(-5) cm s(-1)) and their respective molecular masses (from 417 to 3,432 Da), indicating that other factors dominate nasal permeability. For instance, the permeabilities of metabolically labile peptides were concentration dependent and saturable, as demonstrated for two short thymopoietin fragments, Arg-Lys-Asp (TP3) and Arg-Lys-Asp-Val (TP4). By permeation studies using gonadorelin and two gonadorelin derivatives, buserelin and Hoe 013, without and in the presence of the chemical enhancer bacitracin, we also verified the ability of the model to assess chemical enhancer effects and their reversibility. In conclusion, our work demonstrates the potential of the investigated in vitro model, excised bovine nasal mucosa, to explore mechanistic aspects of nasal transport and metabolism of therapeutic peptides.
authors.affiliation: Department of Applied BioSciences, Swiss Federal Institute of Technology Zurich (ETH), Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors.forename: M C
authors.initials: MC
authors.lastname: Schmidt
authors.forename: D
authors.initials: D
authors.lastname: Simmen
authors.forename: M
authors.initials: M
authors.lastname: Hilbe
authors.forename: P
authors.initials: P
authors.lastname: Boderke
authors.forename: G
authors.initials: G
authors.lastname: Ditzinger
authors.forename: J
authors.initials: J
authors.lastname: Sandow
authors.forename: S
authors.initials: S
authors.lastname: Lang
authors.forename: W
authors.initials: W
authors.lastname: Rubas
authors.forename: H P
authors.initials: HP
authors.lastname: Merkle
mesh_terms: D000042:Absorption; D000626:Aminopeptidases / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D002116:Calcitonin / Q000378:metabolism; D002417:Cattle; D002463:Cell Membrane Permeability / Q000187:drug effects; D004594:Electrophysiology; D005079:Excipients; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000378:metabolism; D008954:Models, Biological; D009297:Nasal Mucosa / Q000378:metabolism*; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D015203:Reproducibility of Results; D013946:Thymopoietins / Q000378:metabolism
chemical_list: D005079:Excipients; D004364:Pharmaceutical Preparations; D013946:Thymopoietins; C028815:salmon calcitonin; D002116:Calcitonin; D000626:Aminopeptidases