Isopropyl Myristate-Modified Polyether-Urethane Coatings as Protective Barriers for Implantable Medical Devices

Abstract

Polyurethane films have potential applications in medicine, especially for packaging implantable medical devices. Although polyether-urethanes have superior mechanical properties and are biocompatible, achieving water resistance is still a challenge. Polyether based polyurethanes with two different molecular weights (PTMO1000, PTMO2000) were prepared from 4,4’-diphenylmethane diisocyanate and poly(tetra-methylene oxide). Polymer films were introduced using different concentrations (0.5-10 wt %) of isopropyl myristate lipid (IPM) as a non-toxic modifying agent. The physical and mechanical properties of these polymers were characterised using physical and spectroscopy techniques (FTIR, Raman, DSC, DMA, tensile testing). Water contact angle and water uptake of the membranes as a function of IPM concentration was also determined accordingly. The FTIR and Raman data indicate that IPM is dispersed in polyurethane at ≤ 2wt% and thermal analysis confirmed this miscibility to be dependent on soft segment length. Modified polymers showed increased tensile strength and failure strain as well as reduced water uptake by up to 24% at 1-2 wt% IPM.

Polyurethane Membranes Modified with Isopropyl Myristate as a Potential Candidate for Encapsulating Electronic Implants: A Study of Biocompatibility and Water Permeability

“…The IPM containing polymer shows an absorption band at 2,950 cm −1 due to asymmetric stretching of surface [26]. We have shown that, IPM is well dispersed in PEU-2 with concentrations ≤2 wt% and that there is sufficient IPM at or near surface to influence surface energy [26].…”

“…Finally, if IPM leaches out from polymer matrix it will not have adverse effect on surrounded tissue due to its biocompatibility. We have already reported on a significant improvement in the mechanical properties and water uptake for IPM containing polyurethane [26]. The previous study indicate that the optimum is derived for over 1-2 wt% IPM.…”

“…We have shown that, IPM is well dispersed in PEU-2 with concentrations ≤2 wt% and that there is sufficient IPM at or near surface to influence surface energy [26]. It could be explained by considering the desire of molecules to orient in a way that minimizes the interfacial energy.…”

“…In this study, two series of polyether-urethanes with different soft segment length and hard segment contents were synthesised and loaded with different concentrations of IPM as previously reported [26]. The aim of this work was to evaluate the effect of IPM incorporation on in vitro cell compatibility and water transport properties of the blend.…”

Assessment of aliphatic poly(ester-carbonate-urea-urethane)s potential as materials for biomedical application

“…Hard segments are derivatives of diisocyanates and chain extenders. Soft segments are introduced with the oligomerol, among which the most common are oligoestrols [8][9][10], oligoetherols [11][12][13], and oligocarbonate diols [14]. Poly(ester-urethane)s (PEUs) undergo significant hydrolytic degradation in vivo; therefore, they are unsuitable for longterm implants [15,16].…”