Gels for constant and smart delivery of insulin

Abstract

The focus of this review is the role of gelatinous materials for oral, transdermal and peritoneal insulin platforms as alternatives to the ubiquitous subcutaneous depot approach. Hydrogels that form hydrated, cohesive materials and the topologically complex micellar types can add ligand interaction, bond vulnerability and rheological characteristics to develop reliable programmed release, including closed loop (automated basal and bolus) activity in non-oral routes. In addition, the potential protection of the protein and likely increased paracellular uptake mean that orally active insulin is feasible. While unlikely to be suitable for closed loop delivery, the driver for gut absorption is not only to increase the convenience and decrease dosage trauma, but to target the mesentery-portal vasculature rather than peripheral tissue, thus improving hepatic glycogen equilibrium and reducing the obesogenic effect and hypoglycaemic episodes.

Polyelectrolyte Gels: A Unique Class of Soft Materials

“…In Figure 6, the quantity Y is plotted as a function of time for spherical gels with different initial diameters. At higher values of t, all gels exhibit a linear behavior, as predicted by Equation (10), in agreement with the expectation that the relaxation time decreases with decreasing gel size. B1 is, however, the same for the four gel samples shown in Figure 5, indicating that the ratio of the moduli G/Mos is independent of the gel size The values of τ1 and B1 obtained from the fits were used to calculate Dc.…”

“…This is due to the ability of PNIPAM to squeeze out the absorbed drug when the temperature is near that of the human body. Glucose sensors are used in insulin delivery systems [10]. Another important application of smart gels is scaffolds for tissue engineering because they are capable of releasing cells in response to a stimulus [11,12].…”

‘Smart’ insulin-delivery technologies and intrinsic glucose-responsive insulin analogues

“…Polymer-based GRI technologies are challenged by limited particle stability [93,94], lag times and suboptimal insulinresponse rates leading to hyperglycaemic or hypoglycaemic excursions. Addressing these limitations has encountered a catch-22: sensitising matrices to hyperglycaemia, for example, can limit their ability to attenuate insulin release at low glucose concentrations.…”

Novel Black Seed Polysaccharide Extract-g-Poly (Acrylate) pH-Responsive Hydrogel Nanocomposites for Safe Oral Insulin Delivery: Development, In Vitro, In Vivo and Toxicological Evaluation

“…Currently, no Food and Drug Administration (FDA) approved oral insulin formulation is commercially available [ 13 ]. Therefore, this is a topic of great interest to develop a novel drug delivery system for safe oral delivery of insulin [ 7 , 14 ].…”