Implants and biodegradable tissue markers

Patent metadata

Field	Value
Publication number	US-2017266324-A1
Application number	US-201715613555-A
Country	US
Kind code	A1
Filing date	Jun 5, 2017
Priority date	Dec 15, 2009
Publication date	Sep 21, 2017
Grant date	—

Abstract

Implantable materials may be used in an iatrogenic site. Applications include radioopaque materials for fiducial marking.

First claim

1 . A method for radiation therapy comprising
introducing a hydrogel spacer at a site between a first tissue location and a second tissue location to increase a distance between the first tissue location and the second tissue location, with site being chosen to decrease radiation at the first tissue when the second tissue receives a dose of therapeutic radiation, wherein introducing the hydrogel spacer comprises placing one or more flowable synthetic precursors at the site that undergo a covalent crosslinking reaction to make, at the site, a covalently-crosslinked biodegradable hydrogel implant that has a covalently attached radiopaque agent.

2 . The method of claim 1 wherein the spacer provides a fiducial marker for administration of the therapeutic radiation.

3 . The method of claim 2 further comprising visualizing the interface of the fiducial marker and the second tissue.

4 . The method of claim 3 wherein the visualization comprises CT, MRI, or X-ray.

5 . The method of claim 1 further comprising making a radiation plan based on a visualization of the hydrogel, with the hydrogel being in contact with the second tissue.

6 . The method of claim 5 , with the plan having a reduced uncertainty in target definition relative to a radiation plan made without the hydrogel.

7 . The system of claim 1 wherein degradation products of the hydrogel spacer comprise a polyethylene glycol covalently bound to the radioopaque agent, with the radioopaque agent comprising iodine.

8 . The method of claim 1 wherein the hydrogel spacer has a Hounsfield number of more than about 50.

9 . The method of claim 1 wherein the hydrogel spacer, as placed in the tissue, has a volume between 1 and 40 ml.

10 . The method of claim 1 wherein the hydrogel spacer is stable, having dimensions that do not appreciably change following implantation for a predetermined amount of time, and thereafter softens and biodegrades.

11 . The method of claim 10 wherein the predetermined amount of time is between 30 and 90 days.

12 . The method of claim 1 with the hydrogel spacer being hydrolytically biodegradable

13 . The method of claim 1 , with the hydrogel spacer being biodegradable to produce only degradation products that are absorbed into the circulatory method and cleared from the body via renal filtration.

14 . The method of claim 1 wherein the hydrogel spacer is a product of a covalent crosslinking chemical reaction between at least two precursors, with one of the precursors comprising a branched polyethylene glycol with at least four arms.

15 . The method of claim 1 wherein between 25% and 90% of the arms comprise the radioopaque agent.

16 . The method of claim 15 wherein the branched polyethylene glycol has a molecular weight from 10,000 to 100,000 Daltons.

17 . The method of claim 1 wherein the hydrogel spacer is made from precursors that have no more than three contiguous amino acids.

18 . The method of claim 1 further comprising visualizing margins of the hydrogel implant with a machine selected from the group consisting of magnetic resonance imaging, X-ray, and computerized tomography.

19 . The method of claim 1 further comprising passing the one or more flowable synthetic precursors in aqueous medium through a needle of 27 gauge or a smaller diameter.

20 . The method of claim 1 wherein the hydrogel spacer is completely biodegradable at a time between about 30 and about 365 days.

21 . The method of claim 1 further comprising a therapeutic agent in the hydrogel spacer.

22 . The method of claim 1 further comprising a radiation source in the hydrogel spacer.

23 . The method of claim 1 , with the radiopaque agent being present in the hydrogel spacer at a concentration of at least about 0.1% w/w.

24 . The method of claim 1 wherein the radioopaque agent comprises iodine.

Assignees

• Incept Llc

Inventors

• Campbell Patrick
• Sawhney Amarpreet S

Classifications

• A61P35/00

  Antineoplastic agents · CPC title

• A61P43/00

  Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00 · CPC title

• A61P15/00

  Drugs for genital or sexual disorders (for disorders of sex hormones A61P5/24); Contraceptives · CPC title

• A61L31/18

  Materials at least partially X-ray or laser opaque · CPC title

• A61K51/1244

  microparticles or nanoparticles, e.g. polymeric nanoparticles · CPC title