US4806470A
Expired / Lapsed
US
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Analytical element and method for theophylline determination having increased alkaline phosphatase isoenzyme
Assignee: Clinical Diagnostic Systems Inc
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Filing: 1986-08-25
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Granted: 1989-02-21
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Expires: 2006-08-25
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 an absorbent carrier material, 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 about 100 I.U./m 2 . This level of isoenzyme reduces or eliminates bias caused by endogenous alkaline phosphatase and hemoglobin during an assay.
Inventors
- 👤 Paul H. Frickey
- 👤 Gary E. Norton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:58
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: 23
Claim 1
Independent Claim
79 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, said first zone containing at least about 100 I.U./m 2 of an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for said isoenzyme at a pH of 9 or less, and said second zone containing a substrate for said isoenzyme.
Claim 2
Dependent Claim
79 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, said first zone containing at least about 100 I.U./m 2 of an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for said isoenzyme at a pH of 9 or less, and said second zone containing a substrate for said isoenzyme.
Claim 3
Dependent Claim
21 words
The element of claim 1 wherein said isoenzyme is present in an amount of at least about 150 I.U./m 2 .
Claim 4
Dependent Claim
18 words
The element of claim 1 where in said substrate is an organic mono- or diester of phosphoric acid.
Claim 5
Dependent Claim
20 words
The element of claim 3 wherein said substrate is selected from the group consisting of p-nitrophenyl phosphate and 4-(4-nitro-2-methylsulfonyl phenylazo)naphthol-1-phosphate.
Claim 6
Dependent Claim
13 words
The element of claim 1 wherein said isoenzyme is bovine liver alkaline phosphatase.
Claim 7
Dependent Claim
107 words
A dry analytical element for the determination of theophylline comprising, in fluid contact, a porous spreading zone and at least one additional zone, said element containing at least about 100 I.U./m 2 of 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, provided said phosphatase and substrate are in different zones of said element, said element further containing a buffer which is capable of maintaining the pH at 9 or less during said determination, provided that substantially all of said buffer is in said porous spreading zone.
Claim 8
Dependent Claim
107 words
A dry analytical element for the determination of theophylline comprising, in fluid contact, a porous spreading zone and at least one additional zone, said element containing at least about 100 I.U./m 2 of 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, provided said phosphatase and substrate are in different zones of said element, said element further containing a buffer which is capable of maintaining the pH at 9 or less during said determination, provided that substantially all of said buffer is in said porous spreading zone.
Claim 9
Dependent Claim
21 words
The element of claim 6 wherein said isoenzyme is present in an amount of at least about 150 I.U./m 2 .
Claim 10
Dependent Claim
14 words
The element of claim 6 wherein said phosphatase substrate is in said spreading zone.
Claim 11
Dependent Claim
100 words
An analytical element for the determination of theophylline comprising: a support having thereon, in order and in fluid contact: a first layer containing at least about 150 I.U./m 2 of an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for said isoenzyme at a pH of 9 or less, a radiation-blocking layer, and a porous spreading layer containing a substrate for said isoenzyme, said element further containing a buffer which is capable of maintaining the pH at 9 or less during said determination, provided that substantially all of said buffer is in said porous spreading layer.
Claim 12
Dependent Claim
100 words
An analytical element for the determination of theophylline comprising: a support having thereon, in order and in fluid contact: a first layer containing at least about 150 I.U./m 2 of an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for said isoenzyme at a pH of 9 or less, a radiation-blocking layer, and a porous spreading layer containing a substrate for said isoenzyme, said element further containing a buffer which is capable of maintaining the pH at 9 or less during said determination, provided that substantially all of said buffer is in said porous spreading layer.
Claim 13
Dependent Claim
17 words
The element of claim 9 further comprising a subbing layer between said radiation-blocking and porous spreading layers.
Claim 14
Dependent Claim
16 words
The element of claim 9 wherein said porous spreading layer is a blush polymer spreading layer.
Claim 15
Dependent Claim
13 words
The element of claim 11 wherein said porous spreading layer comprises titanium dioxide.
Claim 16
Independent Claim
115 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 a dry analytical element 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, said first zone containing at least about 100 I.U./m 2 of an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for said isoenzyme at a pH of 9 or less, and said second zone containing a substrate for said isoenzyme, and B. determining a detectable change resulting from said contact.
Claim 17
Independent Claim
115 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 a dry analytical element 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, said first zone containing at least about 100 I.U./m 2 of an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for said isoenzyme at a pH of 9 or less, and said second zone containing a substrate for said isoenzyme, and B. determining a detectable change resulting from said contact.
Claim 18
Dependent Claim
17 words
The method of claim 13 carried out at a pH of from about 7 to about 9.
Claim 19
Dependent Claim
16 words
The method of claim 13 wherein said biological fluid is human blood serum or whole blood.
Claim 20
Independent Claim
138 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 human biological fluid suspected of containing theophylline with a dry analytical element comprising: a support having thereon, in order and in fluid contact: a first layer containing at least about 150 I.U./m 2 of an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for said isoenzyme at a pH of 9 or less, a radiation-blocking layer, and a porous spreading layer containing a substrate for said isoenzyme, said element further containing a buffer which is capable of maintaining the pH at 9 or less during said determination, provided that substantially all of said buffer is in said porous spreading layer, and B. determining a detectable change resulting from said contact.
Claim 21
Independent Claim
138 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 human biological fluid suspected of containing theophylline with a dry analytical element comprising: a support having thereon, in order and in fluid contact: a first layer containing at least about 150 I.U./m 2 of an isoenzyme of alkaline phosphatase which is capable of acting on a substrate for said isoenzyme at a pH of 9 or less, a radiation-blocking layer, and a porous spreading layer containing a substrate for said isoenzyme, said element further containing a buffer which is capable of maintaining the pH at 9 or less during said determination, provided that substantially all of said buffer is in said porous spreading layer, and B. determining a detectable change resulting from said contact.
Claim 22
Dependent Claim
17 words
The method of claim 16 carried out at a pH of from about 7 to about 9.
Claim 23
Dependent Claim
16 words
The method of claim 16 wherein said human biological fluid is blood serum or whole blood.
References Cited (Backward Citations)
US4264727A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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