Reduction-sensitive functionalized copolyurethanes for biomedical applications

Abstract

In the present paper we combine functionalization and biodegradation in the rational design of polymers that can be used as carrier systems for drug delivery in the colon. Functionalization of new polyurethanes (PUs) was achieved by thiol–ene coupling reactions, a simple and straightforward procedure included among the so-called click reactions, which are currently accepted as one of the most powerful tools in organic chemistry. Enhancement of the degradability of the new materials by the introduction of disulfide linkages into the polymer backbone has led to a new group of stimulusresponsive sugar-based polyurethanes able to be degraded by tripeptide glutathione under physiological conditions. Atomic Force Microscopy (AFM) on solid-supported multilayered dry polymer films— prepared by spin-coating from dimethylsulfoxide solutions—was used to study the morphology of the polymers and the degradation process in reductive environments. Matrix systems containing polymers selected according to their rheological properties were also investigated as modulated methotrexaterelease system

Polyurethanes derived from carbohydrates and cystine‐based monomers

“…The degradation under nitrogen atmosphere proceeded in one stage, with a maximum associated weight loss at temperatures ranging from 282°C to 300°C, and an observed weight loss of above 89%. These values follow a general trend observed in other synthetic polyurethanes and the weight loss could reach 100 wt % when an oxidative atmosphere is used.…”

“…This method is based on glutathione‐mediated lysis under physiological conditions of disulfide bonds incorporated into the polymer skeleton. The general validity of this strategy has been supported by previously published works related with various HMDI‐ and MDI‐PUs …”

Melt polycondensation approach for reduction degradable helical polyester based on l‐cystine

“…Very recently, l ‐cystine diamine was polymerized with fatty dicarboxylic acids in solution polycondensation route to make poly(disulfide amide) nanoparticles for docetaxel delivery . These amino acid‐based poly(disulfide)s were used as nanoscaffolds for delivering anticancer drugs and gene . These examples clearly envisage the importance of the disulfide polymers as reduction degradable thermoplastics and also as useful scaffold material for biomedical applications.…”

Biocompatible and bioreducible micelles fabricated from novel α-amino acid-based poly(disulfide urethane)s: design, synthesis and triggered doxorubicin release

“…[6][7][8] PUs exhibit excellent physical properties and biocompatibility and have been widely used in biomedical implants. 21 The work from different research groups has revealed that reduction-sensitive shell-sheddable micelles, [22][23][24][25][26][27] main chain degradable nanoparticles [28][29][30][31][32] and reversibly crosslinked polymeric nanocarriers [33][34][35][36] display significantly improved in vitro and in vivo anticancer efficacy as compared to the non-sensitive counterparts. [12][13][14][15][16] It is found that drug release from common biodegradable polymeric nanoparticles is generally slow and incomplete, leading to compromised therapeutic efficacy in vitro and in vivo.…”