Polymer and Stability Considerations in Dry Reagent Diagnostic Chemistry

Abstract

The technology basis and principles of dry reagent chemistry in the diagnostic analysis of blood glucose are briefly described. The application of a commercially available enzyme stabilizer mixture enhanced the thermal stability of glucose oxidase and horseradish peroxidase incorporated into an emulsion polymeric system. Dry reagent strips containing both enzymes were incubated at 58°C for up to three weeks. Thermal inactivation of horseradish peroxidase resulted in 21% and 52% loss of original activity with and without the stabilizer, respectively. The combined activities of glucose oxidase-horseradish peroxidase also declined to 29% in strips with and 47% in strips without the stabilizer. Therefore, the inclusion of a suitable enzyme stabilizer in such systems is highly recommended. Methods are proposed for predicting the functional lifetime of a strip as related to its major components.