Enhanced pulmonary absorption of drugs in rats with experimental silicosis.

To investigate the effect of pulmonary silicosis on absorption of drugs from the lung, rats were given an intratracheal injection of 50 mg quartz dust, and rates of drug absorption from silicotic and control lungs were compared at 60 and 120 days after treatment. The pulmonary absorption of procaine amide ethobromide and p-aminohippuric acid was increased by 33-41% in animals with silicosis, whereas absorption of procaine amide in silicotic animals was not significantly different from control. The results suggest that silicosis results in an increased porosity of the pulmonary epithelium.