after a 10 mg/kg s.c. dose , the peak levels of naloxone in brain and plasma were 4.31 mug/g and 1.27 mug/ml , respectively , and extensive localization of extractable free drug and its minor metabolite , naloxol , occurred in tissues with high levels in kidney , spleen , lung , heart , skeletal muscle and somewhat lower concentration in the liver .
C0006104
brain
C0086045
concentration