pH‐responsive release behavior of genipin‐crosslinked chitosan/poly(ethylene glycol) hydrogels

Abstract

Chitosan/poly(ethylene glycol) blends were crosslinked by the nontoxic genipin as a crosslinker to produce the pH‐responsive hydrogels. The pH‐responsive swelling and releasing behavior of chitosan/poly(ethylene glycol) hydrogels was studied by varying the contents of poly(ethylene glycol) (PEG) and genipin, and the molecular weights of PEG. The drug release increased as the pH of the medium decreased, because the protonation of amino acids in chitosan chains at the acidic condition caused the higher swelling of hydrogels. The drug release increased as the content of PEG increased, because the larger pores were formed in the hydrogel and the higher swelling of matrix was obtained. The drug release decreased with the increase of the content of genipin, because the higher degree of crosslinking impeded the diffusion of drug from the hydrogel matrix. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A pH-sensitive theranostics system based on doxorubicin conjugated with the comb-shaped polymer coating of quantum dots

“…PGMAg-EDA (average molecular weight:1.13 9 10 4 gmol -1 ) was synthesized in our laboratory as described in previous paper. 21 Polyethylene glycol monomethyl ether (mPEG-OH, average molecular weight of 2000 gmol -1 ), EDC, and NHS were purchased from Aldrich. CdSe/ZnS QDs (capped with ligand octadecylamine (ODA), k ex = 543 nm) were purchased from Ocean Nanotech LLC.…”

“…PGMA-g-EDA-g-PEG was synthesized by grafting PGMA-g-EDA with PEG-COOH. The theme of this strategy was based upon the idea that PEG is usually used as a protective layer on the surface which is important in preventing nonspecific interaction and stimulation to the immune system during circulation in nanosized delivery systems [21]. In here, PGMA-g-EDA was synthesized in our previous work [22].…”

Biodegradable Polysaccharides for Controlled Drug Delivery

“…Polysaccharides have been added to other synthetic biodegradablep olymers in order to impart desired properties such as improved mechanical strength, swelling capability with retention of shape, endowment of pH sensitivity and enhancement of biodegradability.S uperabsorbent hydrogels with favorable swelling and mechanical properties were obtained by crosslinking various polysaccharides and polysaccharide-synthetic mixtures such as tara gum-acrylica cid, [46] bacterial cellulose-acrylic acid, [47] dextran-poly(e-caprolactone), [48] chitosanpoly(ethylene glycol), [49] chitosan-cyclodextrin, [50] modified hemicellulose-N-isopropylacrylamide, [51] CMC-poly(acrylic acid), [52] modified chitosan-carbopol, [53] alginate-poly(N-vinyl-2pyrrolidone), [54] alginate-polyacrylamide, [55] chitosan-chondroitin-6-sulfate, [56] psyllium-acrylamide and 2-acrylamido-2-methylpropanesulfonic acid, [57] psyllium-acrylic acid, [58] xanthanpoly(acrylic acid)-poly(vinyl alcohol) [59] and chitosan-gelatin, [60] chitosan-poly(vinyla lcohol). [61] These semisynthetic hydrogels have aw ide variety of biomedical applications, such as controlledr elease drugd elivery, [47,57,[61][62] wound dressings, [61,63] tissue engineering [36,64] and gene therapy.…”

A facile in situ morphological characterization of smart genipin-crosslinked chitosan–poly(vinyl pyrrolidone) hydrogels

“…Similar findings have also been observed for genipin-crosslinked chitosan-poly(ethylene oxide) hydrogels where the same gravimetric regime was also used to evaluate smart behavior. 31,32 Previous reports on the mechanical properties of genipin-crosslinked chitosan hydrogels show promise toward the development of a biomedical application. 33 However, long-term stability remains a challenge.…”