US5525334A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for vascular embolization
Assignee: National Institute of Advanced Industrial Science and Technology
•
Filing: 1995-03-22
•
Granted: 1996-06-11
•
Expires: 2015-03-22
Abstract
Abstract Proposed is a method for vascular embolization of the blood vessel of a patient by introducing an aqueous solution of a specific thermosensitive polymer, which is liquid at low temperatures but causes coagulation when heated up to the body temperature of the patient, into the blood vessel followed by in situ heating of the solution. The thermosensitive polymer found to be suitable for the purpose is a homopolymer or copolymer of an N-substituted (meth) acrylamide monomer having a specified intrinsic viscosity in tetrahydrofuran and gives an aqueous solution capable of exhibiting phase transition from a liquid to a coagulate at a transition temperature of 10° to 37°.
Inventors
- 👤 Shoji Ito
- 👤 Yuji Matsumaru
- 👤 Takashi Hirano
- 👤 Shinichi Ohashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:41
CPC Classifications
A; A61; A61K; A61K31/00; A61K31/74; A61K31/785; A61P; A61P7/00; A61P9/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
196 words
A method for vascular embolization of a blood vessel of a patient which comprises the steps of: (a) injecting, into the blood vessel of the patient, an aqueous solution containing from 0.5% to 50% by weight of a thermosensitive polymer consisting of the monomeric units comprising a monomeric moiety derived from an N-substituted (meth) acrylamide compound and represented by the general formula ##STR2## in which R 1 is a hydrogen atom or a methyl group, R 2 is a hydrogen atom, an alkyl group or an alkoxy-substituted alkyl group and R 3 is an alkyl group or an alkoxy-substituted alkyl group, having an intrinsic viscosity [η] in the range from 0.01 to 6.0 dl/g in tetrahydrofuran at 27° C. and having a transition temperature for coagulation of the aqueous solution by the phase transition of the polymer into a coagulate within a range from 10° to 37° C., at a temperature lower than the transition therapeutically acceptable temperature; and (b) heating the aqueous solution of the thermosensitive polymer inside of the blood vessel up to a temperature higher than the transition temperature of the thermosensitive polymer either externally or by the body temperature of the patient.
Claim 2
Independent Claim
196 words
A method for vascular embolization of a blood vessel of a patient which comprises the steps of: (a) injecting, into the blood vessel of the patient, an aqueous solution containing from 0.5% to 50% by weight of a thermosensitive polymer consisting of the monomeric units comprising a monomeric moiety derived from an N-substituted (meth) acrylamide compound and represented by the general formula ##STR2## in which R 1 is a hydrogen atom or a methyl group, R 2 is a hydrogen atom, an alkyl group or an alkoxy-substituted alkyl group and R 3 is an alkyl group or an alkoxy-substituted alkyl group, having an intrinsic viscosity [η] in the range from 0.01 to 6.0 dl/g in tetrahydrofuran at 27° C. and having a transition temperature for coagulation of the aqueous solution by the phase transition of the polymer into a coagulate within a range from 10° to 37° C., at a temperature lower than the transition therapeutically acceptable temperature; and (b) heating the aqueous solution of the thermosensitive polymer inside of the blood vessel up to a temperature higher than the transition temperature of the thermosensitive polymer either externally or by the body temperature of the patient.
Claim 3
Dependent Claim
41 words
The method for vascular embolization of the blood vessel of a patient as claimed in claim 1 in which the molar fraction of the monomeric units derived from the N-substituted (meth) acrylamide compound in the thermosensitive polymer is at least 10%.
Claim 4
Dependent Claim
39 words
The method for vascular embolization of the blood vessel of a patient as claimed in claim 1 in which the concentration of the thermosensitive polymer in the aqueous solution is in the range from 1 to 30% by weight.
Claim 5
Dependent Claim
40 words
The method for vascular embolization of the blood vessel of a patient as claimed in claim 1 in which the thermosensitive polymer has an intrinsic viscosity [η] in the range from 0.1 to 2.0 dl/g in tetrahydrofuran at 27° C.
Claim 6
Dependent Claim
18 words
The method of claim 1, wherein the monomeric moiety is a mixture of N-isopropyl acrylamide and N-n-propyl acrylamide.
References Cited (Backward Citations)
US4732930A
Cited
US5202352A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-06-11 | 1999-12-11 | 2000-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-11 | 2003-12-11 | 2004-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-11 | 2007-12-11 | 2008-06-11 | $7700.00 | Window Closed / Lapsed |