Self-assembled Oral Nanocarriers Targeting Intestinal Lymphatic System for Treatment of Pancreatic Diseases

Abstract

Pancreas are most important part of human body carrying out exocrine and endocrine functions. Exocrine function includes the digestion of food by enzymes, whereas the endocrine includes the secretion of the insulin which metabolizes the glucose. The location of the pancreas is visceral and situated beneath the liver in the arc of the duodenum. While growing in development and influence of the western diet, we are going to be diabetic capital soon. However, there are other disease which severely affects the pancreas which are complex and untreatable. The disease includes Pancreatic ductal adenocarcinoma (PDAC) and Pancreatitis, both disease carries major burden of pancreas associated disease and due to their complex nature remains untreated with reports of inconvenient treatment procedure. The current treatment procedure involves intravenous injections and requires expert to monitor the dose of the medicament. So, there is burning need for the development of effective, patient friendly and safe drug or drug delivery system for the treatment of these disease. Delivering a medicine via oral route is most preferred, convenient and safer route of drug delivery, however it comes with several challenges including influence of the gastric enzymes and pH as well as the first pass metabolism. With the advancement in the development of nanocarrier system we can modify the carrier and drug bioavailability according to the need of the disease and location of organ affected. There are several drug carrier systems developed protecting the drug and nanocarrier in gastric pH and delivering drug to the site affected named as targeted drug delivery system. In this thesis we have developed such nanocarrier system preferably suitable for oral route of administration for the treatment of pancreatic disease. The pancreas location is complex and the supply or absorption of the nutrients was carried out by lymphatic system mainly intestinal lymphatic system (ILS) which is made of enterocytes and Microfold cells (M-Cells), enterocytes carries out the internalization of lipophilic molecules, whereas M-cells carries out internalization of antigens and other particles. Intestinal lymphatic absorption after oral drug delivery is basically governed by either phagocytosis via M-cells of Peyer’s patches or enterocytes cells. In contrast to other epithelial cells, M-cells does not have mucus layer covering and direct contact of M-cells to lymphoid follicle, easy to excess for macrophages, lymphocytes and dendritic cells. viiiThis thesis comprises of the development patient friendly nanocarrier system for the site-specific targeting and treatment of pancreas associated diseases. We have developed two types of drug delivery system with different approach and unique absorption pathways for oral route of administration. First, we have developed enteric coated effervescent granules of poorly water-soluble drug for enhancing oral bioavailability of luteolin, which self-assembled to form drug loaded nanomicelles, when comes in contact with intestinal aqueous environment after oral administration. We utilized Intestinal lymphatic system (ILS) for enhancing oral absorption of drug. We extensively characterized this system and proved its efficacy by in-vitro and in-vivo methods, observed potentially suppressing pancreatic cancer. Further, we have synthesized polymeric nanoparticle decorated with β-glucan over PLGA nanoparticles for oral drug delivery for treatment of acute and chronic pancreatitis. We developed β-Glucan conjugated PLGA nanoparticles (GNPs) for intestinal lymphatic based oral targeted delivery of Amlexanox (AMX) for pancreatitis treatment. β-glucan is ligand for Dectin-1 receptor which are present on M-cells which helps in internalization by intestinal lymphatic system (ILS). We emphasized on active targeting using nano-modification which helps in targeting drug and nanoparticles in mesenteric lymph node. In-vitro cellular uptake study shows nanoparticles efficiently uptaken by M-cells and LPS activated (M1 polarized) macrophages. We assessed the in-vitro efficacy of nanoparticles and observed that the GNPs are effectively inhibiting the inflammation in pro- inflammatory macrophages by mitigating the inflammatory cytokines. We assessed the GNPs in in-vivo acute and chronic pancreatitis in L-arginine induced experimental animal model. We evaluated the GNPs potential as well as the biodistribution path of absorption and the mechanism of anti-inflammatory activity. We observed that it was protected in the gastric environment and effectively uptaken by ILS, subsequently carried by macrophages toward inflammatory site by Chemotaxis. Further, the trypsin enzyme present in inflamed site breaks the ester bond and releases the drug in inflamed site only. We observed promising results which are proven by several molecular techniques. Overall, this thesis presents several novel approaches for enhancing the oral delivery of poorly water-soluble drugs, with a focus on targeting pancreatic diseases through efficient drug carrier systems and exploiting the intestinal lymphatic pathway for site-specific delivery and improved therapeutic outcomes.