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US5352436A Expired / Lapsed US ⏱️ 0.0 years remaining

Surfactant-stabilized microbubble mixtures, process for preparing and methods of using the same

Assignee: Drexel University
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Filing: 1993-11-22
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Granted: 1994-10-04
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Expires: 2013-11-22
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Abstract

Abstract The present invention is a mixture including a solvent, a first surfactant and a second, dispersible surfactant different from the first surfactant, the mixture having stabilized gas microbubbles formed therein by sonication. The gas microbubbles are useful in ultrasonic diagnostics. Preferably the first surfactant is substantially soluble in the solvent and the second surfactant is substantially insoluble in the solvent. The present invention also includes a process for preparing the stabilized gas microbubbles and a method for altering the contrast of an ultrasonic image using the microbubbles as a contrast agent.

Inventors

  • 👤 Margaret A. Wheatley
  • 👤 Shen Peng
  • 👤 Shruti Singhal
  • 👤 Barry B. Goldberg

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 06:54
CPC Classifications
A; A61; A61K; A61K49/00; A61K49/22; A61K49/222; A61K49/223

Claims Analysis

Total Claims: 29
Claim 1
Independent Claim 49 words
A mixture having stabilized gas microbubbles formed therein by sonication, the gas microbubbles having a mean diameter of less than about 10 micrometers, and being for use in ultrasonic diagnostics, comprising a substantially aqueous solvent; a first surfactant; and a second, substantially water-dispersible surfactant different from the first surfactant.
Claim 2
Dependent Claim 49 words
A mixture having stabilized gas microbubbles formed therein by sonication, the gas microbubbles having a mean diameter of less than about 10 micrometers, and being for use in ultrasonic diagnostics, comprising a substantially aqueous solvent; a first surfactant; and a second, substantially water-dispersible surfactant different from the first surfactant.
Claim 3
Dependent Claim 16 words
A mixture according to claim 1, wherein said first surfactant is substantially soluble in said solvent.
Claim 4
Dependent Claim 12 words
A mixture according to claim 1, wherein said first surfactant is non-ionic.
Claim 5
Dependent Claim 16 words
A mixture according to claim 1, wherein said first surfactant comprises a polyoxyethylene fatty acid ester.
Claim 6
Dependent Claim 37 words
A mixture according to claim 4, wherein said polyoxyethylene fatty acid ester is selected from the group consisting of polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate and mixtures thereof.
Claim 7
Dependent Claim 16 words
A mixture according to claim 1, wherein said second surfactant is substantially insoluble in said solvent.
Claim 8
Dependent Claim 12 words
A mixture according to claim 1, wherein said second surfactant is non-ionic.
Claim 9
Dependent Claim 16 words
A mixture according to claim 1, wherein said second surfactant comprises a sorbitan fatty acid ester.
Claim 10
Dependent Claim 26 words
A mixture according to claim 8, wherein said sorbitan fatty acid ester is selected from the group consisting of sorbitan monostearate, sorbitan monopalmitate, and mixtures thereof.
Claim 11
Dependent Claim 24 words
A mixture according to claim 1, wherein the ratio of first surfactant to second surfactant is between about 1:0.5 to about 1:1.5 by weight.
Claim 12
Dependent Claim 19 words
A mixture according to claim 1, wherein the molar ratio of first surfactant to second surfactant is about 1:1.7.
Claim 13
Dependent Claim 24 words
A mixture according to claim 1, wherein the concentration of said microbubbles is between about 1×10 7 and about 1×10 10 particles/ml of mixture.
Claim 14
Dependent Claim 13 words
A mixture according to claim 1, wherein said solvent comprises a saline solution.
Claim 15
Dependent Claim 25 words
A mixture according to claim 13, wherein said saline solution is a phosphate saline solution having a pH ranging from about 7.0 to about 7.5.
Claim 16
Dependent Claim 92 words
A process for preparing stabilized gas microbubbles having a mean diameter of less than about 10 micrometers, and being for use in ultrasonic diagnostics, comprising the steps of: (a) mixing a solvent, a first surfactant and a second, dispersible surfactant to form a mixture, said second surfactant being different from said first surfactant; (b) generating microbubbles having a mean diameter of less than about 10 micrometers in said mixture by exposing said mixture to ultrasound sonication; (c) collecting said microbubbles by separating at least a portion of said solvent from said microbubbles.
Claim 17
Dependent Claim 92 words
A process for preparing stabilized gas microbubbles having a mean diameter of less than about 10 micrometers, and being for use in ultrasonic diagnostics, comprising the steps of: (a) mixing a solvent, a first surfactant and a second, dispersible surfactant to form a mixture, said second surfactant being different from said first surfactant; (b) generating microbubbles having a mean diameter of less than about 10 micrometers in said mixture by exposing said mixture to ultrasound sonication; (c) collecting said microbubbles by separating at least a portion of said solvent from said microbubbles.
Claim 18
Dependent Claim 17 words
A process according to claim 15, wherein said solvent comprises a saline solution to form said mixture.
Claim 19
Dependent Claim 16 words
A process according to claim 15, wherein said first surfactant is substantially soluble in said solvent.
Claim 20
Dependent Claim 16 words
A process according to claim 15, wherein said second surfactant is substantially insoluble in said solvent.
Claim 21
Dependent Claim 22 words
A process according to claim 15, wherein said mixture is exposed to said ultrasound sonication for about 1 to about 3 minutes.
Claim 22
Dependent Claim 64 words
A process according to claim 15, wherein the step of generating microbubbles further comprises permitting said microbubbles to form an intermediate layer comprising microbubbles, each microbubble having a diameter less than about 10 μm, said intermediate layer being located between a lower layer which substantially comprises said solvent and an upper layer which substantially comprises bubbles having a diameter greater than about 10 μm.
Claim 23
Dependent Claim 26 words
A process according to claim 20, wherein the step of collecting said microbubbles comprises separating said intermediate layer from said lower layer and said upper layer.
Claim 24
Dependent Claim 18 words
A process according to claim 15, further comprising an additional step of washing said microbubbles with a solvent.
Claim 25
Dependent Claim 19 words
A process according to claim 15, further comprising an additional step of cooling said mixture to a first temperature.
Claim 26
Dependent Claim 14 words
A process according to claim 15, wherein said first temperature is about 4° C.
Claim 27
Independent Claim 103 words
A method for altering the contrast of an ultrasonic image, comprising the steps of: forming a mixture of a solvent, a first surfactant and a second, dispersible surfactant, said second surfactant being different from said first surfactant, said mixture having stabilized gas microbubbles with a mean diameter of less than about 10 micrometers formed therein by sonication; collecting said microbubbles by separating at least a portion of said solvent from said microbubbles; and injecting said microbubbles into a body, whereby said microbubbles are effective to substantially alter the contrast of an ultrasonic image of a portion of the body containing said microbubbles therein.
Claim 28
Independent Claim 103 words
A method for altering the contrast of an ultrasonic image, comprising the steps of: forming a mixture of a solvent, a first surfactant and a second, dispersible surfactant, said second surfactant being different from said first surfactant, said mixture having stabilized gas microbubbles with a mean diameter of less than about 10 micrometers formed therein by sonication; collecting said microbubbles by separating at least a portion of said solvent from said microbubbles; and injecting said microbubbles into a body, whereby said microbubbles are effective to substantially alter the contrast of an ultrasonic image of a portion of the body containing said microbubbles therein.
Claim 29
Dependent Claim 28 words
A method according to claim 25, further comprising the step of substantially evenly distributing said microbubbles within a saline solution prior to injecting said microbubbles into said body.

References Cited (Backward Citations)

US4466442A Cited
US4615879A Cited
US4684479A Cited
US4832941A Cited
US4774958A Cited
US4764574A Cited
US4844882A Cited
US4957656A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1997-10-03 1998-04-04 1998-10-04 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2001-10-03 2002-04-04 2002-10-04 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2005-10-03 2006-04-04 2006-10-04 $7700.00 Window Closed / Lapsed

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