EP0258034A2
Expired / Lapsed
EP
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Analytical element and method for theophylline determination using buffer in spreading zone
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 comprises a porous spreading zone and at least one other zone in fluid contact with the spreading zone. The isoenzyme of alkaline phosphatase and a suitable substrate for the isoenzyme are located in different zones of the element. The element also contains a buffer for maintaining the pH at 9 or less, substantially all of which is located in the porous spreading zone.
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
2026-10-29 23:43
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/52; G01N33/525; G01N33/526; C; C12; C12Q; C12Q1/00; C12Q1/34; C12Q1/42; C12Q2334/00; C12Q2334/10; Y; Y10; Y10S; Y10S435/00; Y10S435/805; Y10S436/00; Y10S436/822
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
101 words
A dry analytical element for the determination of theophylline comprising, in fluid contact, a porous spreading zone and at least one additional zone, the element 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 a substrate for the isoenzyme, provided the phosphatase and substrate are in different zones of the element, the element characterized in that it further contains a buffer which is capable of maintaining the pH at 9 or less during the determination, substantially all of which is in the porous spreading zone.
Claim 2
Dependent Claim
101 words
A dry analytical element for the determination of theophylline comprising, in fluid contact, a porous spreading zone and at least one additional zone, the element 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 a substrate for the isoenzyme, provided the phosphatase and substrate are in different zones of the element, the element characterized in that it further contains a buffer which is capable of maintaining the pH at 9 or less during the determination, substantially all of which is in the porous spreading zone.
Claim 3
Dependent Claim
15 words
The element as claimed in claim 1 wherein the buffer is a nitrogen-containing organic buffer.
Claim 4
Dependent Claim
22 words
The element as claimed in either of claims 1 and 2 wherein the buffer is tris(hydroxymethyl)aminomethane·HCl, glycylglycine, N-tris(hydroxymethyl)-methyl-2-aminoethanesulfonic acid or N-2-hydroxyethylpiperazine-Nʹ-2-ethanesulfonic acid.
Claim 5
Dependent Claim
20 words
The element as claimed in any of claims 1 to 3 wherein the phosphatase substrate is in the spreading zone.
Claim 6
Dependent Claim
32 words
The element as claimed in any of claims 1 to 4 wherein the substrate is an organic mono- or diester of phosphoric acid and the phosphatase isoenzyme is bovine liver alkaline phosphatase.
Claim 7
Dependent Claim
26 words
The analytical element as claimed in any of claims 1 to 5 further comprising a radiation-blocking zone between the additional zone and the porous spreading zone
Claim 8
Dependent Claim
22 words
The element as claimed in any of claims 1 to 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 carried 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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