Analytical element and method for determination of theophylline by enzyme inhibition
US4782016A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 18, 1985 |
| Grant date | Nov 1, 1988 |
| Priority date | — |
| Expiry date | Jan 18, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S436/822
- WIPO fieldBiotechnology
- WIPO sectorChemistry
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 at 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.