A long‐term in vitro biocompatibility study of a biodegradable polyurethane and its degradation products

Abstract

The biological safety of degradation products from degradable biomaterials is very important. In this study a new method is proposed to test the cytotoxicity of these degradation products with the aim to save time, laboratory animals, and research funds. A biodegradable polyurethane (PU) foam was subjected to this test method. The PU had soft segments of DL-lactide/epsilon-caprolactone and hard segments synthesized from butanediol and 1,4-butanediiosocyanate. Copolymer foams without urethane segments, consisting of DL-lactide/epsilon-caprolactone, were tested as well. Accumulated degradation products were collected by degrading the foams in distilled water at 60 degrees C up to 52 weeks. Cell-culture medium was prepared from powder medium with this water. In different tests the cytotoxicity of this medium was established. The first signs of cytotoxicity were observed after 3-5 weeks of degradation. This accounts for both materials and reestablishes the good short-term biocompatibility of these materials. The PU showed more toxicity toward the end stages of degradation in comparison with the copolymer. This is probably related to the accumulation of degradation products of the urethane segments. In the in vivo situation the degradation of the PU and the metabolism and excretion of degradation products may differ. Therefore, long-term in vivo studies will have to establish whether these in vitro results are representative for the in vivo behavior of the degrading PU.

Synthesis, In Vitro Degradation, and Mechanical Properties of Two-Component Poly(Ester Urethane)Urea Scaffolds: Effects of Water and Polyol Composition

“…3,[7][8][9]36 Another report suggests that urethane linkages in poly(ester urethane)s prepared from aliphatic polyisocyanates do not hydrolyze significantly. 37 Scaffolds intended for tissue repair and regeneration should be porous and allow nutrient flow and cell ingrowth. 10 Porous PEUUR foams supported better cell attachment (Fig.…”

Characterization, biodegradability and blood compatibility of poly[(R)‐3‐hydroxybutyrate] based poly(ester‐urethane)s

“…X denotes I, II, III, or IV, and n:m denotes the molar feed ratio of PHB-diols to PCL-diols. 2 , stannous 2-ethylhexanoate; PUI, PUII, PUIII and PUIV are poly(ester-urethane)s using four different reaction conditions respectively. PUX(n:m) denotes the poly(ester-urethane)s using the reaction condition of PUX according to Table III.…”

“…To investigate whether the catalyst or solvent with little toxicity could be used instead of those with much toxicity in this reaction system, we synthesized several groups of copolymers using different catalysts and different solvents under several reaction conditions in the presence of PHBdiols and PCL-diols and then studied their molecular weights (Table III). Differences of the average molecular weights of poly(ester-urethane)s using DBTDL as a catalyst (PUI) and that of the ones using Sn(Oct) 2 (PUII and PUIV) were insignificant, indicating that DBTDL and Sn(Oct) 2 had similar effects on catalyzing the synthesis of these poly(ester-urethane)s. Although the synthesis using 1,4-dioxane (PUIII) as a solvent clearly led to lower average molecular weight PU copolymers than those using 1,2-dichloroethane (PUI, PUII and PUIV), this could be attributed to its bad solubility in the reaction system, suggesting that 1,4-dioxane as a solvent was not so effective as 1,2-dichloroethane in this synthetic system. Therefore, Sn(Oct) 2 could be used as a catalyst with less toxicity in this reaction system instead of DBTDL.…”

Flexible, stretchable and implantable PDMS encapsulated cable for implantable medical device

“…To address this limit, complex materials of polyurethane (PU) and other materials were used as an insulation material for commercial implantable lead of defibrillator. Despite of its several advantages, PU is not as stretchable and degradable [6,7,[12][13][14][15][16][17]. Stretchable, biocompatible, resistant to body fluid, flexible and softer cables are needed for small IMDs to be implanted into limited space surrounded by vulnerable tissue.…”