A CLEARANCE MODEL OF MAN-MAN VITREOUS FIBERS (MMVFs) IN THE RAT LUNG

Abstract

Short-term inhalation experiments have been recently performed in rats to evaluate the biopersistence of man-made vitreous fibers (MMVFs). The number and size distribution of inhaled fibers in the rat lung were measured at different postexposure time points. These data were used for developing a mathematical model to describe the clearance kinetics of MMVFs in the rat lung. The model proposed a breakage scheme for long fibers during clearance. The breakage rates for different MMVFs were determined from the fiber size distribution data at different time points. The calculated breakage rate appears to be related to the in vitro dissolution rate; the more soluble a fiber, the faster the fiber breaks.