Title:  Polymerizable biodegradable polymers including carbonate or dioxanone linkages

United States Patent:  6,177,095

Assignee:  Focal, Inc (Lexington, MA)

Filed:  January 7, 2000

Water-soluble macromers including at least one hydrolysable linkage formed from carbonate or dioxanone groups, at least one water-soluble polymeric block, and at least one polymerizable group, and methods of preparation and use thereof are described. The macromers are preferably polymerized using free radical initiators under the influence of long wavelength ultraviolet light or visible light excitation. Biodegradation occurs at the linkages within the extension oligomers and results in fragments which are non-toxic and easily removed from the body. The macromers can be used to encapsulate cells, deliver prophylactic, therapeutic or diagnostic agents in a controlled manner, plug leaks in tissue, prevent adhesion formation after surgical procedures, temporarily protect or separate tissue surfaces, and adhere or seal tissues together.

SUMMARY OF THE INVENTION

Biocompatible, biodegradable, polymerizable and at least substantially water-soluble macromers and methods of preparation and use thereof are disclosed. The macromers are block copolymers that include at least one water-soluble block, at least one biodegradable block, and at least one polymerizable group. At least one of the biodegradable blocks comprises a linkage based on a carbonate or dioxanone group, and the macromers can contain other degradable linkages or groups in addition to carbonate or dioxanone.

The carbonate and dioxanone linkages impart more elasticity to the polymer and degrade at a different rate than hydroxy acid linkages. Carbonate linkages can also increase macromer viscosity, at a given concentration, without requiring increased molecular weight of the nondegradable components of the macromer. The macromers can also include poly(hydroxy acid) linkages which degrade by hydrolysis into relatively non-toxic hydroxy acid residues, or other biodegradable blocks such as polycaprolactones, polyorthoesters, polyanhydrides, and polypeptides. The degradation time of the polymers can be controlled, for example, by selecting the types and proportion of the biodegradable blocks.

The polymerizable groups can be polymerized by either free radical (homolytic) processes or by heterolytic processes (such as cationic polymerization). Preferably, the groups are polymerized photochemically. The macromer can be polymerized in the presence of prophylactic, therapeutic or diagnostic agents, for delivery of the incorporated agents in a controlled manner as the resulting polymer degrades. The macromers are useful for delivering hydrophobic, hydrophilic and/or labile materials. They can be particularly useful for delivery of hydrophobic materials.

The macromers can be polymerized in an interfacial manner to form ultrathin coatings which are intimately adhered to the coated surface, or in a bulk manner to form relatively thick coatings which may or may not be intimately adhered to the coated surface. Alternatively, the two methods can be combined to provide a relatively thick coating which is intimately adhered to the surface. Each of these methods is advantageous for certain applications.

Claim 1 of 23 Claims

We claim:

1. A method for forming a polymeric, biocompatible coating on tissue comprising:

a) applying to the tissue surface a polymerization initiator capable of initiating polymerization via free radical or cationic polymerization;

b) applying to the initiator-coated surface a solution of a biodegradable, polymerizable macromer with a solubility of at least one gram/liter in aqueous solutions at a temperature in the range between about 0 and 50^oC. comprising at least one water soluble region, at least one degradable region, and at least one functional group capable of being polymerized via free radical or cationic polymerization, wherein the polymerizable regions are separated from each other by at least one degradable region and wherein at least one degradable region is a carbonate or dioxanone region; and

c) polymerizing the macromer.

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