Inhaled thiol and phosphorothiol radioprotectors fail to protect the mouse lung.

Pretreatment with an inhaled aerosol of WR 2721, cysteamine or N-acetylcysteine failed to influence the development of radiation-induced lung damage at 14-16 weeks as assessed by a rise in breathing rate in the mouse. In contrast, intraperitoneal WR 2721 400 mg/kg and cysteamine 230 mg/kg were effective indicating that, unlike N-acetylcysteine, they are effective radioprotectors if correctly delivered.