Hydrogels that undergo volumetric expansion in response to changes in their environment and their methods of manufacture and use
First Claim
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1. A method for treating a disease, deformation or disorder of a human or veterinary patient by introduction of a hydrogel polymer through the lumen of a catheter and into an implantation site within the patient'"'"'s body, said method comprising the steps of:
- (A) predicting the approximate pH that will be present at the implantation site when the hydrogel is implanted;
(B) providing a dried, expandable hydrogel that has been prepared by a process comprising the steps of, (i) combining at least a) an cthylenicallyunsauirated monomer or prepolymer having ionizable functional groups, b) a crosslinker and c) a polymerization initiator, to form a hydrogel polymer;
(ii) contacting the hydrogel with a treatment solution, the pH of said treatment solution and the time and temperature of said contact being such that a) functional groups of the hydrogel become protonated and b) the resultant protonated hydrogel will, when subsequently exposed to the pH predicted at the implantation site, undergo deprotonation and expansion at a desired rate of expansion; and
(iii) drying the hydrogel to from a protonated, dried hydrogel mass sized to pass through the catheter lumen;
(C) placing the dried hydrogel mass within the catheter lumen; and
, (D) positioning the catheter at the implantation site and expelling the dried hydrogel mass into the implantation site such that the hydrogel polymer becomes exposed to the pH present at the implantation site and, if the pH present at the implantation site is substantially the same as predicted in Step A, the hydrogel deprotonates and expands at approximately the desired expansion rate, said desired expansion rate being selected such that the hydrogel mass will remain sufficiently small to be retracted into the catheter lumen for at least 15 minutes following its initial exposure to the approximate pH predicted to be present at the implantation site.
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Abstract
Hydrogels that expand volumetrically in response to a change in their environment (e.g., a change in pH or temperature) and their methods of manufacture and use. Generally, the hydrogels are prepared by forming a liquid reaction mixture that contains a) monomer(s) and/or polymer(s) at least portion(s) of which are sensitive to environmental changes (e.g., changes in pH or temperature), b) a crosslinker and c) a polymerization initiator. If desired, a porosigen may be incorporated into the liquid reaction mixture to create pores. After the hydrogel is formed, the porosigen is removed to create pores in the hydrogel. The hydrogel may also be treated to cause it to assume a non-expanded volume in which it remains until a change in its environment causes it to expand. These hydrogels may be prepared in many forms including pellets, filaments, and particles. Biomedical uses of these hydrogels include applications wherein the hydrogel is implanted in the body of a patient and an environmental condition at the implantation site causes the hydrogel to expand in situ.
170 Citations
35 Claims
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1. A method for treating a disease, deformation or disorder of a human or veterinary patient by introduction of a hydrogel polymer through the lumen of a catheter and into an implantation site within the patient'"'"'s body, said method comprising the steps of:
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(A) predicting the approximate pH that will be present at the implantation site when the hydrogel is implanted;
(B) providing a dried, expandable hydrogel that has been prepared by a process comprising the steps of, (i) combining at least a) an cthylenicallyunsauirated monomer or prepolymer having ionizable functional groups, b) a crosslinker and c) a polymerization initiator, to form a hydrogel polymer;
(ii) contacting the hydrogel with a treatment solution, the pH of said treatment solution and the time and temperature of said contact being such that a) functional groups of the hydrogel become protonated and b) the resultant protonated hydrogel will, when subsequently exposed to the pH predicted at the implantation site, undergo deprotonation and expansion at a desired rate of expansion; and
(iii) drying the hydrogel to from a protonated, dried hydrogel mass sized to pass through the catheter lumen;
(C) placing the dried hydrogel mass within the catheter lumen; and
,(D) positioning the catheter at the implantation site and expelling the dried hydrogel mass into the implantation site such that the hydrogel polymer becomes exposed to the pH present at the implantation site and, if the pH present at the implantation site is substantially the same as predicted in Step A, the hydrogel deprotonates and expands at approximately the desired expansion rate, said desired expansion rate being selected such that the hydrogel mass will remain sufficiently small to be retracted into the catheter lumen for at least 15 minutes following its initial exposure to the approximate pH predicted to be present at the implantation site. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for preparing an environmentally-sensitive hydrogel polymer, said method comprising the steps of:
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(A) selecting a desired expansion rate at which it is desired for the hydrogel to expand from a first volume to a second volume;
(B) predicting an environmental condition with which the hydrogel will subsequently come into contact;
(C) forming a reaction mixture that contains at least i) monomer and/or prepolymer having iomizable functional groups, ii) a crosslinker, and iii) an initiator, (D) allowing the monomer and/or prepolymer to become crosslinked by the crosslinker to form a hydrogel that will expand when immersed in an aqueous liquid; and
,(E) treating the hydrogel by contacting the hydrogel with a treatment solution which causes protonation of the functional groups for a time and at a temperature selected to render the hydrogel sensitive to the environmental condition predicted in Step B such that when the hydrogel comes into contact with that predicted environmental condition the hydrogel will expand at approximately the desired expansion rate selected in Step A. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification
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Current AssigneeMicrovention Incorporated (Terumo Corporation)
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Original AssigneeMicrovention Incorporated (Terumo Corporation)
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InventorsCruise, Gregory M., Constant, Michael J.
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Primary Examiner(s)Azpuru, Carlos A.
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Application NumberUS09/804,935Publication NumberTime in Patent Office1,491 DaysField of Search424/423, 424/484, 424/485, 424/486, 424/487, 424/488, 424/422, 424/489, 424/501, 514/772.3US Class Current424/423CPC Class CodesA61K 49/0457 Semi-solid forms, ointments...A61K 9/0024 Solid, semi-solid or solidi...A61L 31/145 Hydrogels or hydrocolloidsC08F 22/385 Monomers containing two or ...
