EP0258035A2
Expired / Lapsed
EP
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Analytical element and method for theophylline determination having increased alkaline phosphatase isoenzyme
Assignee: Eastman Kodak Co
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Filing: 1987-08-25
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Granted: —
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Expires: 2007-08-25
Abstract
Abstract Theophylline can be determined with an analytical element 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 contains a suitable buffer and first and second zones in fluid contact. The isoenzyme of alkaline phosphatase and a suitable substrate for the isoenzyme are located in different zones of the element. The isoenzyme is present in one of the zones in an amount of at least 100 I.U./m². This level of isoenzyme reduces or eliminates bias caused by endogenous alkaline phosphatase and hemoglobin during an assay.
Inventors
- 👤 Paul Henry c/o Eastman Kodak Company Frickey
- 👤 Gary Edward c/o EASTMAN KODAK COMPANY Norton
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 01:48
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/34; C12Q1/42; G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/52; C12Q2334/00; C12Q2334/10; Y; Y10; Y10S; Y10S435/00; Y10S435/805
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
92 words
A dry analytical element for the determination of theophylline 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 first zone containing 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 containing a substrate for the isoenzyme, the element characterized in that the alkaline phosphatase isoenzyme is present in an amount of at least about 100 I.U./m².
Claim 2
Dependent Claim
92 words
A dry analytical element for the determination of theophylline 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 first zone containing 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 containing a substrate for the isoenzyme, the element characterized in that the alkaline phosphatase isoenzyme is present in an amount of at least about 100 I.U./m².
Claim 3
Dependent Claim
21 words
The element as claimed in claim 1 wherein the isoenzyme is present in an amount of at least about 150 I.U./m².
Claim 4
Dependent Claim
23 words
The element as claimed in either of claims 1 and 2 wherein the substrate is an organic mono- or diester of phosphoric acid.
Claim 5
Dependent Claim
21 words
The element as claimed in any of claims 1 to 3 wherein the substrate is p -nitrophenyl phosphate or 4-(4-nitro-2-methylsulfonyl phenylazo)naphthol-1-phosphate.
Claim 6
Dependent Claim
19 words
The element as claimed in any of claims 1 to 4 wherein the isoenzyme is bovine liver alkaline phosphatase.
Claim 7
Dependent Claim
20 words
The element as claimed in any of claims 1 to 5 wherein the second zone is a porous spreading zone.
Claim 8
Dependent Claim
18 words
The element as claimed in claim 6 wherein the porous spreading zone is a blush polymer spreading layer.
Claim 9
Independent Claim
54 words
A method for the determination of theophylline comprising the steps of: A. at a pH of 9 or less, contacting a sample of a biological fluid suspected of containing theophylline with the dry analytical element as claimed in any of claims 1 to 7, and B. determining a detectable change resulting from the contact.
Claim 10
Dependent Claim
17 words
The method as claimed in claim 8 caried out at a pH of from 7 to 9.
Claim 11
Independent Claim
22 words
The method as claimed in either of claims 8 and 9 wherein the biological fluid is human blood serum or whole blood.
References Cited (Backward Citations)
No citation records indexed.
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