Lyophilisation Improves Bioactivity and Stability of Insulin-Loaded Polymeric-Oligonucleotide Nanoparticles for Diabetes Treatment

Abstract

The oral bioavailability of therapeutic proteins is limited by the gastrointestinal barriers. Encapsulation of labile proteins into nanoparticles is a promising strategy. In order to improve the stability of nanoparticles, lyophilisation has been used to remove water molecules from the suspension. Although various cryoprotections were employed in the preparation of lyophilised nanoparticles, the selection of cryoprotectant type and concentration in majority of the developed formulation was not justified. In this study, nanoparticles were fabricated by cationic chitosan and anionic Dz13Scr using complex coacervation. The effect of cryoprotectant types (mannitol, sorbitol, sucrose and trehalose) and their concentrations (1, 3, 5, 7, 10% w/v) on physiochemical properties of nanoparticles were measured. Cellular assays were performed to investigate the impact of selected cryoprotectant on cytotoxicity, glucose consumption, oral absorption mechanism and gastrointestinal permeability. The obtained results revealed that mannitol (7% w/v) could produce nanoparticles with small size (313.2 nm), slight positive charge and uniform size distribution. The addition of cryoprotectant could preserve the bioactivity of entrapped insulin and improve the stability of nanoparticles against mechanical stress during lyophilisation. The gastrointestinal absorption of nanoparticles is associated with both endocytic and paracellular pathways. With the use of 7% mannitol, lyophilised nanoparticles induced a significant glucose uptake in C2C12 cells. This work illustrated the importance of appropriate cryoprotectant in conservation of particle physiochemical properties, structural integrity and bioactivity. An incompatible cryoprotectant and inappropriate concentration could lead to cake collapse and formation of heterogeneous particle size populations.

Chitosan Nanoparticles in Atherosclerosis—Development to Preclinical Testing

“…As chitosan has various beneficial effects on human health, for instance, in bone healing [ 48 , 49 ], it makes it quite an ideal biomaterial to employ in the drug delivery research sector. Various labs, including ours [ 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ], have shown that chitosan is capable of encapsulating various types of therapeutic agents such as small molecule drugs to exploratory biologicals such as proteins and even DNA in delivery platforms of various sizes. As chitosan can even be ingested with no complications, this fact further cements the usefulness of this biopolymer in drug delivery R&D. Chitosan NPs have been formulated in the past using various methods, not limited to complex coacervation [ 64 ] and ionotropic gelation [ 65 ], both simple enough to carry out in most labs.…”

C2C12 cell model: its role in understanding of insulin resistance at the molecular level and pharmaceutical development at the preclinical stage

“…[43,205,216,217] Nanoparticles possess several favourable properties, including stability against enzymatic degradation, improved bioavailability and high carrier capacity. [218][219][220][221] One of the studies examined the antidiabetic effects of bioflavonoids-loaded nanoparticles on C2C12 cells and streptozotocin-induced diabetic rat model. [121] It was found that nanoparticles containing myricitrin (1, 3, and 10 mg/kg) could increase glycogen synthesis and its storage, GLUT-4 gene expression, glucose uptake and cell viability in C2C12 cells.…”

Preparation of Solid Lipid Nanoparticles and Nanostructured Lipid Carriers for Drug Delivery and the Effects of Preparation Parameters of Solvent Injection Method

“…Coacervation has been widely used to produce polymeric nanoparticles [ 133 , 134 ] and was first used by Battaglia et al to prepare SLNs in 2010 [ 135 ]. This method is based on the acidification-induced precipitation of the alkaline salts of fatty acids.…”