DYNAMIC VAPOR GENERATION AND HEAD SPACE DETERMINATION OF M-XYLENE FORPHARMACOKINETIC STUDIES

A custom designed vapour generation-exposure chamber assembly and head space analysis method were evaluated for use in pharmacokinetic inves tigations. The predicted in-xylene concentration was within 1% of the average Value measured by gas chromatography-flame ionization detectio n (GC-FID) in the glass exposure chamber during controlled vapourizati on of m-xylene. The concentration variability was +/- 13% and +/- 4%, respectively, with and without rats in the chamber. Blood and tissue s amples from male, Sprague Dawley rats exposed to 1100 ppm of xylene, w ere analyzed by means of a static head space (HS)-GC analysis method. The average m-xylene level in the blood of exposed animals was ca. 500 0 ng/mL. m-Xylene was detected in brain, kidney, skin, fat and liver. The analytical precision for duplicate samples was < +/- 5% for all ti ssues, except liver and skin. The feasibility of detection of m-xylene in unhomogenized tissue by HS-GC analysis was demonstrated.