Clearance of benzo(a)pyrene from the respiratory tract of hamsters following its intratracheal instillation with or without ferric oxide.

A comparative study was carried out on the clearance of benzo(a)pyrene (BP) from the respiratory tract of Syrian golden hamsters following intratracheal instillation of either BP alone or BP attached to ferric oxide particles. Eight series of 18 hamsters each, received a single intratracheal instillation of 0.5 or 1.0 mg BP suspended in 0.9% NaCl solution. In addition, three comparable series of hamsters received in the same way a mixture, of 1.0 mg BP + 1.0 mg ferric oxide suspended in 0.9% NaCl solution. In each of the series the BP content of the respiratory tract was determined at six different points of time viz. immediately after administration of BP or BP + ferric oxide, and three, six and 24 hours, and three and seven days after an instillation. The clearance of BP from the respiratory tract did not appear to be significantly influenced by the presence of ferric oxide. It was concluded that the present study produced no evidence of ferric oxide particles being capable of enhancing the retention of BP in the respiratory tract.