Impact of gavage dosing procedure and gastric content on adverse respiratory effects and mortality in rat toxicity studies.
J Appl Toxicol
; 31(4): 342-54, 2011 May.
Article
en En
| MEDLINE
| ID: mdl-21089156
Unscheduled mortality preceded by adverse respiratory clinical signs in rats dosed by oral gavage may not only be caused by technical gavage error or systemic toxicity but may also be caused by gastro-esophageal reflux and subsequent aspiration of high concentrations of drug formulation. In a 3 week oral gavage rat toxicity study for an early drug development compound, preterminal deaths (approximately 20% of animals) at high doses (≥1000 mg kg(-1) ) and concentrations (≥60 mg ml(-1) ) were preceded by recurrent dyspnea, rales or excessive salivation, without evidence of accidental intrapulmonary gavage error. Histological evaluation revealed extensive necrosis and inflammatory changes in the upper respiratory tract, especially in the nasal turbinates and/or nasopharynx. The presence of food particles in inflammatory exudates suggested a retrograde aspiration of stomach content with test formulation via the nasopharyngeal duct into the posterior region of the nose. In contrast, no mortality or adverse respiratory effects were observed in rats following 2 week intravenous administration at comparable exposures or oral gavage administration at lower concentrations (≤20 mg ml(-1) ). In a pharmacology study, the compound caused a dose-dependent increase in gastric content (partly due to inhibition of gastric emptying), providing a pharmacological basis for the suspected gavage-mediated gastroesophageal reflux. Reducing the dose volume and dosing fasted animals substantially reduced or eliminated the respiratory effects and mortality at the high test article concentrations, demonstrating that the adverse effects are related to the gavage method.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Reflujo Gastroesofágico
/
Pruebas de Toxicidad
/
Disnea
/
Aspiración Respiratoria
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Contenido Digestivo
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Intubación Gastrointestinal
Límite:
Animals
Idioma:
En
Revista:
J Appl Toxicol
Año:
2011
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Reino Unido