The drug (I5NP) is a small interfering RNA that is being developed to protect patients from acute kidney injury after cardiac bypass surgery. This study will test the safety of I5NP and measure how long the drug stays in the blood stream after injection. This study is not meant to test if I5NP protects kidneys from the damage that may occur in rare cases during surgery. Another purpose of this dose escalation study is to find out the right dose of the experimental drug to be given to study subjects in future studies. Even though there were no harmful effects seen in the animals tested, we do not know what side effects the experimental drug might cause in humans.