Novel hydrogels based on a polyasparthydrazide. Synthesis and characterization

Abstract

α,β‐polyasparthydrazide (PAHy), a synthetic water‐soluble biocompatible polymer, was chemically crosslinked with ethyleneglycol diglycidylether (EGDGE), in order to obtain water swellable microparticles. These were characterized by means of FT‐IR spectrophotometry and by means of particle size distribution analysis. The mean pore size of the prepared gels at various crosslinking ratios and the fractal dimensions were determined by light scattering measurements. Swelling measurements gave evidence of the high affinity of PAHy‐EGDGE microparticles towards aqueous media at different pH values. The physical state of the prepared networks was evaluated by means of X‐rays diffractometry and thermal analysis. A peculiar effect of the degree of crosslinking on the glass transition temperature (Tg) value was shown. In vitro chemical and enzymatic stability studies suggested that the prepared samples do not undergo any degradation after treatment at pH 1, 7.4 and 10 as well as after incubation with enzymes such as pepsin and α‐chymotrypsin.

Polyaspartylhydrazide Copolymer-Based Supramolecular Vesicular Aggregates as Delivery Devices for Anticancer Drugs

“…PAHy is a freely water soluble, biocompatible, nontoxic and nonantigenic polymer, which has been used for the synthesis of macromolecular prodrugs 16 and for the preparation of polymeric hydrogel for controlled drug delivery. 17,18 In this paper, three new polyaspartylhydrazide copolymers containing hydrophobic butyric moieties (PAHy-C4) or both butyric and (carboxypropyl)trimethylammonium hydrochloride (CPTA) moieties, as positively charged groups, the last one linked to the polymeric backbone at two different amounts, were prepared and molecularly characterized. PAHy copolymers so obtained have been used to prepare SVAs with the rational to obtain SVAs bearing hydrophobized PAHy copolymers anchored to the bilayer by hydrophobic C 4 portions and exposing on the surface of the bilayer just the hydrophilic backbone and, in the other case, together with hydrophilic chain also positive charged groups.…”

Scaffolds based on hyaluronan crosslinked with a polyaminoacid: Novel candidates for tissue engineering application

“…Because of its physicochemical properties and biocompatibility, PAHy has been proposed as a plasma expander, carrier for macromolecular prodrugs and starting material to prepare hydrogels by chemical crosslinking using glutaraldheyde or ethylenelyglycoldiglycidyl ether, as well as, by γ‐irradiation after its derivatization with glycidyl methacrylate. The obtained PAHy hydrogels are biocompatible like native PAHy, able to swell in aqueous media and to release drug molecules in simulated biological fluids 16–20. We suppose that PAHy, for its protein‐like structure, biocompatibility and chemical versatility could be useful to obtain new composite scaffolds with HA showing an improved cell affinity, elasticity, and resistance towards chemical and enzymatic degradation.…”

PH responsive polypeptide based polymeric micelles for anticancer drug delivery

“…Hydrazone linkage is fairly stable at neutral pH but rapidly hydrolyzes in the acidic environment at pH < 6.8, which can be formed under very mild conditions. In this work, polyasparthydrazide (PAHy), a derivative of poly(α,β‐aspartic acid) (PAsp), prepared by hydrazinolysis of the polysuccinimide (PSI), was chosen for fabricating the amphiphilic copolymer due to its highly water solubility, biodegradable, nontoxic, nonantigenic, easily produced in large quantities at reasonable cost, and the hydrazine side groups for formation of hydrazone bonds. PEG and aliphatic chain (C18) were grafted to the polymer by hydrazone linkages to form the amphiphilic comb‐type block copolymer with removable hydrophilic and hydrophobic side chains.…”