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Hyaluronic acid (HA)-based prodrugs bearing double-responsive (acid pH or oxidation) boronates of catechol-containing drugs were used to treat xenografted human prostate tumours (LNCaP) in SCID mice. The HA prodrugs accumulated significantly only in tumours (impressively, up to 40% of the injected dose after 24 h) and in liver, with negligible – actually anti-inflammatory - consequences in the latter. A quercetin-HA prodrug significantly slowed down tumour growth, in a dose-dependent fashion and with a much higher efficacy (up to 4 times) than equivalent doses of free quercetin. In short, boronated HA appears to be a very promising platform for targeted chemotherapy.

Copolymerisation of charged and neutral monomers is a well-tested strategy to introduce charged moieties in a polymeric chain and obtain polyelectrolyte polymers. We have synthesized new cationic and anionic polyelectrolytes by bulk radical copolymerisation of 2-hydroxyethyl methacrylate with [2-methacryloyloxyethyltrimethyl ammonium chloride (METAC)] or [2-acrylamido-2-methylpropane-sulphonic acid (AMPS)] monomers. The chemical structure of the synthesized copolymers was confirmed by FT-IR spectroscopy. Swelling studies on synthesized copolymers showed a high water content in the swollen state and a “smart behaviour” upon changes in external stimuli (pH and ionic strength). Cytotoxicity and cytocompatibility studies demonstrated that synthesized materials were not toxic. Moreover, the cationic copolymer showed good cell adhesion, whereas the anionic copolymer showed poor cell adhesion on its surface. X-ray photoelectron spectroscopy (XPS) showed that the disparate behaviour was due to the chemical nature of charged groups on the copolymer surfaces.

Polyelectrolite hydrogels were submitted to the biomimetic method. The experimental results clearly show that the method has coated them with HA globular crystals of similar to 500 nm in diameter. Moreover, the method strongly influences the swelling of the hydrogels. The results strongly suggest that a biologically active HA layer forms also on the surface of the internal pores. Therefore, it is a powerful method for producing micro- and nano-patterned structures of biologically active apatite on the surface of hydrogels and of their pores. (C) 2002 Elsevier Science B.V. All rights reserved.