US5690968A
Expired / Lapsed
US
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Analgesic anaesthetic compositions
Assignee: University of Aberdeen
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Filing: 1994-04-21
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Granted: 1997-11-25
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Expires: 2014-04-21
Abstract
Abstract An analgesic anaesthetic composition comprising up to 50% v\v nitrous oxide, the balance being oxygen and another respirable gas; characterized by the addition of an analgesically effective amount of an ether-based analgesic anaesthetic disposed in a single container above its pseudo-critical temperature at a pressure of up to 2000 psi, thereby to form and maintain a homogenous analgesic composition.
Inventors
- 👤 John Alexander Strachan Ross
- 👤 Michael Eric Tunstall
- 👤 Robert Colin Rodgers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 00:18
CPC Classifications
A; A61; A61K; A61K33/00; A61P; A61P23/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
69 words
An analgesic anesthetic composition comprising up to 50% v/v nitrous oxide, an analgesically effective amount of an ether-based analgesic anesthetic selected from the group consisting of isoflurane, enflurane, sevoflurane, and desflurane and the balance being oxygen and another respirable gas disposed in a single container above its pseudo-critical temperature at a pressure of up to 2000 psi, thereby to form and maintain an analgesically effective homogenous composition in use.
Claim 2
Dependent Claim
69 words
An analgesic anesthetic composition comprising up to 50% v/v nitrous oxide, an analgesically effective amount of an ether-based analgesic anesthetic selected from the group consisting of isoflurane, enflurane, sevoflurane, and desflurane and the balance being oxygen and another respirable gas disposed in a single container above its pseudo-critical temperature at a pressure of up to 2000 psi, thereby to form and maintain an analgesically effective homogenous composition in use.
Claim 3
Dependent Claim
21 words
A composition according to claim 1 wherein the ether-based analgesic is isoflurane vapour at an amount of up to 0.4% v/v.
Claim 4
Dependent Claim
18 words
A composition according to claim 2 wherein isoflurane vapour constitutes between 0.25% and 0.325% v/v of the admixture.
Claim 5
Independent Claim
155 words
A method of minimizing fluctuations in the concentration of an analgesic anaesthetic composition administered from a pressurized container via a first stage reduction chamber, said composition comprising up to 50% v/v nitrous oxide, an effective amount of an ether-based analgesic anaesthetic selected from the group consisting of isoflurane, enflurane, sevoflurane, and desflurane and a balance of oxygen or other respirable gas mixture, which method comprises at least one of the following steps: (I) maintaining the pressure drop between the container and a first reduction chamber at a value of less than 62 bar; or (II) arranging a 1 liter/minute gas bleed from the reduction chamber associated with the demand flow control mechanism, or (III) mechanically discarding or diluting the first breath after a rest period from the apparatus at the inception of inhalation; or (IV) using an absorbative system in the breathing system to take up any of said ether-based analgesic anaesthetic which has liquidized.
Claim 6
Independent Claim
155 words
A method of minimizing fluctuations in the concentration of an analgesic anaesthetic composition administered from a pressurized container via a first stage reduction chamber, said composition comprising up to 50% v/v nitrous oxide, an effective amount of an ether-based analgesic anaesthetic selected from the group consisting of isoflurane, enflurane, sevoflurane, and desflurane and a balance of oxygen or other respirable gas mixture, which method comprises at least one of the following steps: (I) maintaining the pressure drop between the container and a first reduction chamber at a value of less than 62 bar; or (II) arranging a 1 liter/minute gas bleed from the reduction chamber associated with the demand flow control mechanism, or (III) mechanically discarding or diluting the first breath after a rest period from the apparatus at the inception of inhalation; or (IV) using an absorbative system in the breathing system to take up any of said ether-based analgesic anaesthetic which has liquidized.
Claim 7
Dependent Claim
13 words
A method according to claim 4 wherein the ether-based analgesic anaesthetic is isoflurane.
References Cited (Backward Citations)
DE2524956A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-11-24 | 2001-05-26 | 2001-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-11-24 | 2005-05-26 | 2005-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-11-24 | 2009-05-26 | 2009-11-25 | $7700.00 | Window Closed / Lapsed |