Analytical element and method for theophylline determination having increased alkaline phosphatase isoenzyme
US4806470A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 25, 1986 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | Aug 25, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S435/805
- WIPO fieldMeasurement
- WIPO sectorInstruments
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.sup.2. This level of isoenzyme reduces or eliminates bias caused by endogenous alkaline phosphatase and hemoglobin during an assay.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.