Cyanuric chloride as the basis for compositionally diverse lipids

In vivo assessment of triazine lipid nanoparticles as transfection agents for plasmid DNA

Non-viral vectors for in vivo delivery of plasmid DNA rely on optimized formulations to achieve robust transgene expression. Several cationic lipids have been developed to deliver nucleic acids, but most recent literature has focused on mRNA due to its increased expression profile and excluded plasmid DNA, which may have the advantage of being less immunogenic. In this study, we describe the in vivo evaluation of cationic triazine based lipids, previously prepared by our group. We identify one lipid with limited in vivo toxicity for studies to optimize the lipid formulations, which include an evaluation of the influence of PEG and helper lipids on transgene expression. We then demonstrate that lipoplexes, but not lipid nanoparticles, formed from triazine lipids achieve similar transgene expression levels as AAV vectors and offer enhanced expression as compared to a commercially available cationic lipid, DOTAP. Importantly, the lipid nanoparticles and lipoplexes induce minimal antibody profiles toward the expressed protein, while serving as a platform to induce robust antibody responses when directly delivering the protein. Collectively, these data demonstrate the potential for triazine based lipids as non-viral vectors for gene delivery, and highlights the need to optimize each formulation based on the exact contents to achieve enhanced transgene expression with plasmid DNA constructs.

Optimization and Characterization of a Liposomal Azithromycin Formulation for Alternative Macrophage Activation

Liposomal azithromycin (L-AZM) promotes macrophage polarization toward an M2-like phenotype in the context of myocardial infarction that results in improved cardiovascular outcomes in mice. To improve upon this formulation, we sought to identify optimized formulation, stability, and biological activity parameters necessary to enhance the immunomodulatory activity and efficacy of L-AZM. While our parent formulation contains a mixture of long-chain saturated phosphatidylcholine and phosphatidylglycerol lipids, we evaluated a series of formulations with different amounts of unsaturated lipids and cholesterol with the goal of improving the loading capacity and stability of the formulations. We also introduce fusogenic lipids to improve the cytosolic delivery to enhance the immune modulatory properties of the drug. To achieve these goals, we initially prepared a library of 24 formulations using thin film hydration and assessed the resultant liposomes for size and polydispersity. Five lead formulations were identified based on low polydispersity (<0.3) and stability over time. The lead formulations were then evaluated for stability in serum using dialysis and macrophage polarization activity in vitro as measured by decreased IL-12 expression. Collectively, our data indicate that the formulation components drive the balance between encapsulation efficiency and stability and that all the lead liposomal formulations improve in vitro alternative macrophage activation as compared to free AZM.