Degradable polyurethanes

Storey RF and Hickey TP. Degradable polyurethane networks based on D,L-lacdde, glycohde, e-caprolactone, and trimethylene carbonate homopolyester and copolyester triols. Polymer, 1994, 35, 830-838. 

Woodhouse described a degradable polyurethane prepared with a novel amine chain extending agent. As with the insertion of lactic acid into the backbone, bio-degradability was achieved, but the fragments appeared problematic. Thus, while biodegrading polyurethanes are fairly simple to prepare, one must be aware of the product to which a polyurethane degrades. The use of TDI as the isocyanate would clearly raise concerns from the FDA. 

Skarja, G.A. Woodhouse, K.A. Synthesis and characterization of degradable polyurethane elastomers containing and amino acid-based chain extender. J. Biomater. Sci. Polym. Ed. 1998, 9 (3), 271-295. 

Skarja GA, Woodhouse KA (2000) Structure-property relationships of degradable polyurethane elastomers containing an amino acid-based chain extender. J Appl Polym Sci 75 (12) 1522-1534... 

Renman L., Sangd C., Skarping G. (1986) Determination of isocyanate and aromatic amine emission from thermally degraded polyurethanes in foundries. Am. Ind. Hyg. Assoc. J., 47, 621-628. 

E. Bachelder, T. Beaudette, K. Broaders, S. Paramonov, J. Dashe, J. Frechet, Acid-degradable polyurethane particles for protein-based vaccines biological evaluation and in vitro analysis of particle degradation products, Mol. Pharm. 25 (2008) 876-884. 

Madbouly, S.A. and Lendlein, A. (2012) Degradable polyurethane/soy protein shape-memory polymer blends prepared via environmentally-friendly aqueous dispersions. Macromol. Mater. Eng., 297 (12), 1213-1224. 

Sharifpoor S, Simmons CA, Labow RS and Santerre JP, Functional characterization of human coronary artery smooth muscle cells under cyclic mechanical strain in a degradable polyurethane scaffold. Biomaterials 32 4816-29,2011. 

The resistance of polyurethane elastomers to immersion in water has been identified as relatively poor and is directly applicable to immersion in dilute solutions of inorganic materials in water. Provided the inorganic substance has no catalytic effect the solution can be expected to behave as pure water. However, acidic or alkaline media accelerate hydrolytic attack and therefore solutions of salts of weak acids or bases are likely to degrade polyurethanes faster than water. As a generalization, it can be stated that, provided the pH of a solution lies between the values of 5-5 and 8, the action of the solution can be considered similar to the action of water. At higher acidities or higher alkalinities it is advisable to test the effect of the particular solution. As would be expected, strong acids and bases attack polyurethanes rapidly. 

Table 6.1 Polyols uscd as precursors in the synthesis of degradable polyurethanes for biomedical applications...

Main general applications of degradable polyurethanes in regenerative medicine and drug release... 

Design of new degradable polyurethanes inspired by biodegradation mechanisms... 

Degradable polyurethanes designed with hydrolytically susceptible soft segments... 

Degradable polyurethanes with varying chain extenders... 

Degradable polyurethanes cultured with stem cells for tissue engineering applications... 

Commercial degradable polyurethanes used in stem cell culture... 

Degradable polyurethanes used in drug delivery systems... 

Cheung JW, Jain D, McCnUoch C, Santerre P. Pro-angiogenic character of endothelial cells and gingival fibroblasts co-cnltnres in perfused degradable polyurethane (D-PHI) scaffolds. Tissue Eng Part A May, 2015 21(9-10) 1587-99. http //dx.doi.org/10.1089/ ten.TEA.2014.0548. Epnb 2015 Mar 10. 

Battiston KG, Ouyang B, Labow RS, Simmons CA, Santerre JP. Monocyte/macrophage cytokine activity regulates vascular smooth muscle cell function within a degradable polyurethane scaffold. Acta Biomater March 2014 10(3) 1146-55. 

McBane JE, Cai K, Labow RS, Santerre JP. Co-culturing monocytes with smooth muscle cells improves cell distribution within a degradable polyurethane scaffold and reduces inflammatory cytokines. Acta Biomater February 2012 8(2) 488-501. 

Cheung JW, McCulloch CA, Santerre JP. Establishing a gingival fibroblast phenotype in a perfused degradable polyurethane scaffold mediation by TGE-betal, FGF-2, betal-integiin,andfocal adhesion kinase. Biomaterials December 2014 35(38) 10025-32. 

Fromstein, J.D., Zandstra, P.W., Alperin, C., Rockwood, D., Rabolt, J.F., Woodhouse, K.A., 2008. Seeding bioreactor-produced embryonic stem cell-derived cardiomyocytes on different porous, degradable, polyurethane scaffolds reveals the effect of scaffold architecture on cell morphology. Tissue Engineering Part A 14, 369-378. 

In early experiments, degradable polyurethane scaffolds derived from lysine polyisocyanates and hexamethylene diisocyanate (HDI) were shown to support attachment, proliferation, and differentiation of osteoblasts. To enhance the modest osteoconduc-tivity of polyurethane scaffolds, recent studies have investigated addition of a ceramic component. Both polyurethane scaffolds and polyurethane/ceramic composites have been shown to support new bone formation in a number of preclinical studies. 

Basak, R, Adhikari, B., 2012. Effect of the solubility of antibiotics on their release from degradable polyurethane. Materials Science and Engineering C 32, 2316-2322. http //dx.doi. org/10.1016/j.msec.2012.07.002. 

---