pH-Sensitive Hydrogel Based On A Novel Photocross-Linkable Copolymer

Abstract

A pH sensitive hydrogel has been prepared by a UV irradiation technique. Starting polymer was the PHM (poly hydroxyethylaspartamide methacrylated) obtained from polyaspartamide (PHEA) partially derivatized with methacrylic anhydride (MA). This new copolymer has been further derivatized with succinic anhydride (SA) to obtain PHM-SA that has been cross-linked by UV irradiation to form a pH sensitive hydrogel. The network, recovered after washing as a powder, has been been characterized by FT-IR spectrophotometry and particle size distribution analysis. Moreover, to have information about water affinity of the prepared sample, swelling measurements have been carried out in aqueous media mimicking biological fluids. The possibility to employ the prepared hydrogel as a pH-sensitive drug delivery system (DDS) has been investigated. In particular, ibuprofen ((S)(+)4-isobutyl-alpha-methylphenyl-acetic acid), chosen as a model drug, has been entrapped into the PHM-SA hydrogel, and in vitro release studies have showed that its release rate depends on different swelling of the network as a function of the environmental pH.

Hydrogels for Potential Colon Drug Release by Thiol‐ene Conjugate Addition of a New Inulin Derivative

“…After a few minutes, a suitable amount of TEA was added according to Y ¼ 5, where Y ¼ moles of TEA moles of inulin repeating unit (2) The reaction mixture was placed into a thermostatic bath and stirred at 60 8C under argon for 24 h. After this time, the reaction product was precipitated in 400 mL of ether and centrifuged for 15 min at 10 000 rpm and 4 8C. The product was recovered, washed with ether (5 Â 50 mL) and then dried under a vacuum.…”

“…The particle size distribution appears suitable for a potential control of drug release, as reported elsewhere for similar microparticles. [2] In fact, the rather homogeneous size distribution could determine a uniform delivery from the microparticles.…”

“…The application of hydrogels ranges over many fields: they have been proposed for use in the food industry, [1] as drug delivery systems, [2][3][4][5] biomaterials in tissue engineering and, most generally, in biomedical applications. [6,7] Hydrogels can be prepared from natural, [4,[8][9][10] synthetic [2,3,11] and mixed natural/synthetic polymers. [5,12,13] Hydrogels made from natural polymers offer several advantageous properties, such as native biocompatibility, biodegradability and biologically recognizable moieties that support cellular activities.…”

Hydrogels of Dextran Containing Nonsteroidal Anti-Inflammatory Drugs as Pendant Agents

“…A possible approach for a colon drug release is yielded by pH-sensitive systems, having carboxylic groups in side chain (Mandracchia et al 2004;Giannuzzo et al 2006). These systems, as a consequence of the presence of ionizable groups, show a swelling degree lower at acid pH than in neutral one.…”

Controlled Release of IgG by Novel UV Induced Polysaccharide/Poly(amino acid) Hydrogels

“…[38] In particular, 2 g of a,b-poly[N-(2-hydroxyethyl)-D,L-aspartamide] (PHEA) were dissolved in 40 mL of anhydrous N,Ndimethylacetamide (DMA), and then suitable amounts of triethylamine (TEA) and methacrylic anhydride (MA) were added, according to X 00 ¼ 0.5 and Y 00 ¼ 0.5, where, X 00 ¼ moles of methacrylic anhydride/moles of PHEA repeating unit and Y 00 ¼ moles of TEA/moles of methacrylic anhydride. The reaction was kept at 40 8C under continuous stirring for 48 h. After this time, the reaction mixture was precipitated in 400 mL of 2-propanol and centrifuged for 10 min, at 10 000 rpm and 4 8C.…”