Polymer–protein interaction, water retention, and biocompatibility of a stimuli‐sensitive superporous hydrogel containing interpenetrating polymer networks

Abstract

The swelling of a superporous hydrogel containing poly(acrylic acid-co-acrylamide)/O-carboxymethyl chitosan interpenetrating polymer networks (SPH-IPN) was sensitive toward the pH, ionic strength, and temperature stimuli. With insulin as a model drug, polymerprotein interaction was detected, and it was physical rather than covalent. Freezing water was the majority of the imbibed water in the swollen SPH-IPNs, and the waterretention ability of the polymer against compression and time of exposure at 378C was improved as the amount of the O-carboxymethyl chitosan network increased. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay on AD293 and RBL-2H3 cells and an in situ lactate dehydrogenase assay and morphological study on rat intestine confirmed that the SPH-IPNs had satisfactory biocompatibility. These pronounced properties suggested that the SPH-IPNs could be developed as an attractive peroral delivery vehicle for peptide and protein drugs.

Polymer integrity related absorption mechanism of superporous hydrogel containing interpenetrating polymer networks for oral delivery of insulin

“…Complete clearance of the I-SPH-IPN was noted within 12 h, which confirmed that it would not bring about obstruction of the intestine. In our previous work, minimal interference with the integral structures of intestinal epithelia was observed after I-SPH-IPN administration, which demonstrated its low histological toxicology [12].…”

“…3 and 4). Upon contact with the enzyme solution, the fast swelling of the I-SPH-IPN and P-SPH-IPN allowed a quick entrapment of luminal enzymes [5], and electrostatic interaction as well as hydrogen bonding between enzymes and the ionized groups on the polymeric chains promoted polymerenzyme affinity [12], thus inactivating the proteases. Since I-SPH-IPN and P-SPH-IPN shared the same chemical composition, they were deemed to possess equal affinity towards the enzymes, which accounted for their comparable enzyme incorporation capacity.…”

“…Excessive weights were applied on the polymer, and the water extruded out was collected and weighed. Water retention capacity of the polymer was calculated as the percentage of water retained in the hydrogel matrix at determined pressures [12].…”

Engineered High Swelling Hydrogels

“…[ [128][129][130] Incorporating sodium alginate to improve mechanical properties of superporous hydrogels via making interpenetrating polymer networks.…”

Nanostructured Hydrogels

“…Thus, hydrogels are commonly referred as porous cross-linked polymeric structures able to swell in water and to adjust their dimensions and some other properties, such as water content, porosity, and capacity to retain or release substances entrapped between the chains, according to the surrounding medium conditions. Hydrogels respond to variations in temperature, pH, electric or magnetic fields, light, or to multiple stimuli [7,8]. Because of this feature, hydrogels have attracted much attention in recent decades, since they can also be used for a variety of biomedical applications including controlled drug release systems [9].…”