Type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD) are the pressing problems of the modern medicine. Nowadays there are no drugs approved for clinical use for the treatment of NAFLD and T2DM. One of the promising molecules that can be effective in the treatment of NAFLD and T2DM is 2,4-dinitrophenol, which acts as a proton ionophore, transferring protons into the mitochondrial matrix with the release of heat. But it has side effects (increase of metabolic rate, hyperthermia). Thus, the search for an effective formulation of this molecule for targeted delivery to the liver is of a great importance.
The purpose of this work is the development of a controlled-release nanoformulation of 2,4-dinitrophenol derivatives for intravenous administration. In fulfilment of the target, we used 2,4-dinitrophenol esters with various substituent lengths loaded into liposomes of various lipid composition and polymeric micelles based on poly-(L-lactide-co-)glycolide (PLGA).
An effective 3-fold increase in the encapsulation of 2,4-dinitrophenol esters into liposomes in comparison with free molecule was observed. We investigated the dependence of the sustained release of 2,4-dinitrophenol from liposomes on the lipid composition and the LogP of the ester. It has been proven that the optimal ester chain length should be close to palmitic acid, and the lipid membrane should be composed of phospholipids with a certain phase transition point, depending on the desired release rate. We also demonstrated the possibility of 2,4-dinitrophenol esters to encapsulate in nanoparticles of PLGA block copolymer. In this case, the effectiveness of the molecule loading is increased up to 10 times compared to liposomes and loaded molecules released from the nanocontainer more slowly. Using ATP luciferin-luciferase assay efficacy of each derivative in comparison to free 2,4-dinitrophenol was shown. Also, the in vitro test of the formulations showed prolonged inhibiting ATP synthesis due to sustained release of active molecules.
The results open up the perspectives for future application of liposomes and polymer micelles of 2,4-dinitrophenol derivatives as a proton ionophores, whose task is to transfer protons to the mitochondria with the heat dissipation, that leads to accelerated fats oxidation and, as a result, harm-free medical treatment of T2DM and NAFLD.