Bioabsorbable and Biocompatible Polyurethanes and Polyamides for Medical Devices


Bezwada Biomedical has been granted the issuance of United States Patent No. 7,772,352 entitled, “Bioabsorbable and Biocompatible Polyurethanes and Polyamides for Medical Devices.” This newly-issued patent covers the highly reactive isocyanates that are similar to Methylene bis(phenylisocyanate) (MDI) but are biodegradable and have tunable hydrolytic degradation profiles.
What distinguishes these isocyanates from the commonly used isocyanate, MDI, is the presence of a degradable linkage bridging the aromatic rings instead of the non-degradable methylene group. Furthermore, the degradable linkage in our isocyanates is derived from safe and biocompatible glycolic acid, lactic acid, caprolactone, p-dioxanone and diols. These isocyanates can be used as monomers for preparation of absorbable polyurethanes.

The technology covered in this patent offers the following advantages over the prior art:

  • The degradation rate of these isocyanates is controlled by varying the chain length of the degradable linkage and by varying the safe and biocompatible molecule within the degradable linkage, i.e., replacing glycolide with lactide or p-dioxanone, and the like.
  • Polyurethanes derived from these novel isocyanates and chain extender diols will be not only absorbable but will also possess, for the first time, degradable hard segments.
  • The derived polyurethanes will have the toughness and mechanical properties of that of commercially available medical grade polyurethanes, and the absorbability of commercial biodegradable polymers.
  • Upon hydrolysis, the derived absorbable polyurethanes will degrade into safe and biocompatible degradation products, unlike polyurethanes derived from MDI.

The patent also covers the application of absorbable polyurethanes derived from these isocyanates in a variety of biomedical applications. Some of the key biomedical applications of these absorbable polyurethane include:

  • Tissue adhesives and sealants
  • Adhesion prevention barrier
  • Absorbable scaffolds for tissue engineering
  • Absorbable coatings
  • Controlled release of drugs

This patent represents a significant step and a major technical achievement in creating new class of absorbable polyurethanes.

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