Blood and organ concentrations of tetracycline and doxycycline in female mice. Comparison to males.

In mice treated with 50 micrograms/g i.v. tetracycline (TC) or doxycycline (DC), respectively, drug concentrations have been measured in serum, whole blood, liver, kidneys, lungs, heart, skeletal muscle and bones. TC reached especially high concentrations in liver, kidneys and bones. DC was initially trapped by lung tissue and accumulated in liver and kidneys. Liver concentrations were higher for TC, kidney concentrations were higher for DC. In some tissues, e.g. liver and kidneys, TC and DC reached higher concentrations in females than in males.