The use of a 3rd syringe further increases the possibilities. Now you can load two different test articles into the system to perform studies such as drug-drug interaction, agonist-antagonist, and hepatic enzyme induction. As with the dual syringe, the TEND feature can be selected by the user to maintain catheter patency. The contents of both syringes can be delivered individually or in tandem. The timing of each dose is completely controlled by the user.