Inhalation Toxicologic Procedures for Exposure of Small Laboratory Animals to Highly Toxic Materials: Part A: Exposures to Gasses with Notes on the Toxicity of PFIB

摘要

The estimation of military hazard from toxic materials usually requires an estimate of the human toxicity. With expensive, rare and highly toxic substances, only small amounts of substance may be available for testing or safety considerations may restrict the amounts of material that may be used at one time. A functional system has been developed for the exposure of animals to highly toxic gas or aerosol test materials. Mice may be exposed either nose only or whole body. Rats, guinea pigs and small numbers of larger animals may be exposed nose only. Provision is made to continuously monitor the exposure concentrations of either gasses or aerosols in the test atmospheres. Respiration of the subjects may be continuously monitored during the exposures but because of the nose only configuration, the restraint of the animals precludes observations of behaviour during the exposures. This report covers the system as configured for recirculating exposures to air dissolved chemicals (gasses). Other configurations, covered in companion reports, permit dynamic exposure to both aerosols and gasses. Operation of the recirculating system is described using toxicity estimations to perfluoroisobutylene to CD-1 mice as the trial example. The LC(t50) value obtained was 960 mg.min/cu m for a 10 min exposure, a value that agrees with data generated in other laboratories.