Removal of strontium by the chelating agent acetylamino propylidene diphosphonic acid in rats.

Studies of the effects of the chelating agent, calcium acetylamino propylidene diphosphonic acid (Ca-APDA), on the removal of radioactive strontium with two administration modalities were carried out in rats. The parenteral (intraperitoneal) administration of 150, 300, or 600 mg kg(-1) Ca-APDA was carried out for 3 d, 10 min after exposure of the animals to the strontium injection. On the first day post-treatment, the retention of strontium in the whole body decreased to 90.1%, 83.9%, and 35.1% that of the control level, respectively. The strontium deposited in femur of 600 mg kg(-1) Ca-APDA group was lowered to 28.4% of the control value. A single oral dose of 600 mg kg(-1) Ca-APDA administered simultaneously with, or 10 min after, oral administration of strontium, radionuclide retention in the whole body was reduced after 1 d to 42.9% and 31.9% of the control, respectively; meanwhile the strontium deposited in the femur was reduced to 16.9% and 29.3% of the control. In conclusion, the results indicate the efficacy of the new agent, Ca-APDA, to remove radioactive strontium from the body, or to inhibit the strontium intestinal absorption, in radio-strontium contaminated individuals.