Estimating the Accuracy of Intraperitoneal Drug Administration in Adult Zebrafish

Intraperitoneal injections are commonly used for systemic drug administration in various laboratory animals, including rodents and zebrafish ( Danio rerio ) . Although these fish have rapidly gained popularity in biomedical research, the accuracy of intraperitoneal drug delivery (due to potential leakage from the injection site) has not been previously evaluated in zebrafish. To investigate this issue, we injected adult zebrafish with 10 µL/g of a dye (1% Evans Blue) intraperitoneally and estimated dye leakage by measuring the optical density of water where the fish were kept for 20 min past injection. Overall, we found that intraperitoneal injections resulted in an estimated approximately 10% immediate leakage and approximately 0.01% secondary leakage (of the injected dye volume), confirming the relative accuracy of intraperitoneal injection as a reliable drug delivery method in adult zebrafish.