Chun-Han Chen, Tse-Hung Huang, Ahmed O Elzoghby, Pei-Wen Wang, Chia-Wen Chang, Jia-You Fang

The increasing death rate caused by drug overdose points to an urgent demand for the development of novel detoxification therapy. In an attempt to detoxify tricyclic antidepressant overdose, we prepared a lipid nanoemulsion, called squarticles, as the nanoantidote. Squalene was the major lipid matrix of the squarticles. Here, we present the animal study to investigate both the pharmacokinetic and pharmacodynamic effects of squarticles on amitriptyline intoxication. The anionic and cationic squarticles had average diameters of 97 and 122 nm, respectively. Through the entrapment study, squarticles could intercept 40%-50% of the amitriptyline during 2 h with low leakage after loading into the nanoparticles. The results of isothermal titration calorimetry demonstrated greater interaction of amitriptyline with the surface of anionic squarticles (Ka =28,700) than with cationic ones (Ka =5,010). Real-time imaging showed that intravenous administration of anionic squarticles resulted in a prolonged retention in the circulation. In a rat model of amitriptyline poisoning, anionic squarticles increased the plasma drug concentration by 2.5-fold. The drug uptake in the highly perfused organs was diminished after squarticle infusion, indicating the lipid sink effect of bringing the entrapped overdosed drug in the tissues back into circulation. In addition, the anionic nanosystems restored the mean arterial pressure to near normal after amitriptyline injection. The survival rate of overdosed amitriptyline increased from 25% to 75% by treatment with squarticles. Our results show that the adverse effects of amitriptyline intoxication could be mitigated by administering anionic squarticles. This lipid nanoemulsion is a potent antidote to extract amitriptyline and eliminate it.