J. Janjic, L. Liu, M. Herneisey, E. Lambert, F. Zor, H. Karagoz, V. Gorantla
Keywords: targeted delivery, nanomedicine, inflammation, pain, analgesia, theranostics
Summary:Chronic inflammation driven pathologies and associated chronic pain represent a growing problem worldwide. The rising cost of medical care drove us to reconsider what effective inflammation and pain control need to be. Single dosing and the potential for complete inflammation resolution are the ultimate goals of the presented nanomedicine approach. To achieve these goals we focused on developing immune cell modulating nanomedicine platforms designed to provide long term inflammation and pain control. Specifically we developed macrophage-targeted perfluoropolyether triphasic nanoemulsions as potentially long term analgesics (Janjic et al, JNI 2018, Patel et al, Clin. Imm. 2015). We demonstrated that these nanoemulsions carrying celecoxib (model COX-2 inhibitor) are internalized by macrophages, can effectively reduce macrophage trafficking to sites of inflammation in mouse models, (Patel et al, Clin.Imm. 2015) and can control pain in a rat model up to 5 days post single dose (Janjic et al JNI, 2018). We observed a dramatic reduction of CFA-induced inflammation in mice and reversal of pain behavior to the base line with celecoxib dose reduced more than 100 fold as compared to other studies in the same models. Here, we present novel high dose celecoxib theranostic nanoemulsions redesigned with an extended prolonged (> one month) anti-inflammatory and analgesic action. To achieve these goals we applied a quality by design approach. Specifically, we used failure mode, effects, and criticality analysis (FMECA), which identified the process and composition parameters that were most likely to impact nanoemulsion critical quality attributes (CQAs) of these targeted nanoemulsions. We constructed several types of regression models to fully optimize the nanoemulsions for prolonged anti-inflammatory action. Using mathematical predictive models we found that the presence of perfluorocarbon oil can increase long term colloidal stability, whereas the presence of solubilizer can increase drug loading but decrease long term colloidal stability. (Herneisey, Liu et al, AAPS PharmSciTech 2019) Select nanoemulsion candidates that met preset quality criteria were tested in a CFA mouse model. Whole body live near infra-red (NIRF) imaging (WBI) and histological analyses confirming prolonged analgesic effects (up to 40 days) of single dose, macrophage targeted nanoemulsion treatment are presented. Nanoemulsions (with and without celecoxib) were injected to the mice via tail vein 12 h prior to inflammation induction. Induction of inflammation is provided by subcutaneous CFA injection to the right paw of the animals. Macrophage infiltration at the inflammation site was monitored by near-infrared fluorescence (NIRF) imaging weekly after CFA injection. Animals were sacrificed at select time points corresponding to acute and chronic inflammation, both of the right and left paws were harvested, and tissues were prepared for histology with H&E staining, picrosirius red, immunohistochemistry, and immunofluorescence. Obtained multifaceted results demonstrate that a single dose of celecoxib loaded nanoemulsions provide extended inflammation control, which has the potential to improve both pain and functional outcomes.