EP0188372A2
Expired / Lapsed
EP
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Analytical element, composition, kit and method for determination of theophylline by enzyme inhibition
Assignee: Eastman Kodak Co
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Filing: 1986-01-15
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Granted: —
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Expires: 2006-01-15
Abstract
Abstract Theophylline can be determined with an analytical element, composition, kit and method which utilize the inhibition, by theophylline, of alkaline phosphatase activity on an appropriate substrate. The assay is carried out at a pH of 9 or less. The element comprises an absorbent carrier material, a suitable buffer for maintaining the pH at 9 or less, and, in fluid contact, a first zone containing an isoenzyme of alkaline phosphatase which is capable of activity of pH 9 or less, and a second zone containing a substrate for the isoenzyme. Use of this invention avoids the effect of endogenous alkaline phosphatase found in human biological fluids which has no activity at pH 9 or less.
Inventors
- 👤 Gary Edward Norton
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 22:15
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/34; C12Q1/42; Y; Y10; Y10S; Y10S435/00; Y10S435/805; Y10S436/00; Y10S436/822
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
84 words
1 . A dry analytical element for the determination of theophylline in a human biological fluid comprising an absorbent carrier material. a buffer which maintains the pH at 9 or less during the determination and, in fluid contact, first and second zones, the element characterized in that the first zone contains an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for the isoenzyme at a pH of 9 or less, and the second zone contains a substrate for the isoenzyme.
Claim 2
Dependent Claim
84 words
1 . A dry analytical element for the determination of theophylline in a human biological fluid comprising an absorbent carrier material. a buffer which maintains the pH at 9 or less during the determination and, in fluid contact, first and second zones, the element characterized in that the first zone contains an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for the isoenzyme at a pH of 9 or less, and the second zone contains a substrate for the isoenzyme.
Claim 3
Dependent Claim
17 words
The element as claimed in claim 1 having an outermost porous spreading layer as the second zone.
Claim 4
Dependent Claim
60 words
An analytical composition for the determination of theophylline in a human biological fluid comprising: an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for the isoenzyme at a pH of 9 or less. a substrate for the isoenzyme. and a buffer. the composition characterized in that the buffer maintains the composition pH at 9 or less.
Claim 5
Dependent Claim
60 words
An analytical composition for the determination of theophylline in a human biological fluid comprising: an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for the isoenzyme at a pH of 9 or less. a substrate for the isoenzyme. and a buffer. the composition characterized in that the buffer maintains the composition pH at 9 or less.
Claim 6
Dependent Claim
56 words
A diagnostic kit for the determination of theophylline in a human biological fluid comprising: an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for the isoenzyme at a pH of 9 or less. a substrate for the isoenzyme. and a buffer which maintains the pH of the fluid at 9 or less.
Claim 7
Dependent Claim
56 words
A diagnostic kit for the determination of theophylline in a human biological fluid comprising: an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for the isoenzyme at a pH of 9 or less. a substrate for the isoenzyme. and a buffer which maintains the pH of the fluid at 9 or less.
Claim 8
Independent Claim
72 words
A method for the determination of theophylline in a human biological fluid comprising the steps of: (A) at a pH of 9 or less, physically contacting a sample of fluid with both an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for said isoenzyme at a pH of 9 or less, and a substrate for said isoenzyme, to produce a detectable change, and (B) determining said detectable change.
Claim 9
Independent Claim
72 words
A method for the determination of theophylline in a human biological fluid comprising the steps of: (A) at a pH of 9 or less, physically contacting a sample of fluid with both an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for said isoenzyme at a pH of 9 or less, and a substrate for said isoenzyme, to produce a detectable change, and (B) determining said detectable change.
Claim 10
Dependent Claim
23 words
The invention as claimed in any of claims 1 to 5 wherein the substrate is an organic mono- or diester of phosphoric acid.
Claim 11
Dependent Claim
21 words
The invention as claimed in any of claims 1 to 6 wherein the substrate is p-nitrophenyl phosphate or 4-(4-nitro- 2-methylsulfonyl phenylazo)naphthol-l-phosphate.
Claim 12
Dependent Claim
22 words
The invention as claimed in any of claims 1 to 7 wherein the isoenzyme of alkaline phosphatase is bovine liver alkaline phosphatase.
Claim 13
Dependent Claim
25 words
The invention as claimed in any of claims 1 to 8 wherein the buffer maintains the pH at from 7 to 9 during the determination.
References Cited (Backward Citations)
No citation records indexed.
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