Diagnostics - Stable Aqueous Horseradish Peroxidase

Challenge

The main use of Horseradish peroxidise (HRP) is in diagnostic applications to produce a detectable signal indicating presence of a molecular target. Typically, HRP is used in conjugates with antibodies - the antibody to recognise the molecular target and the HRP to produce a detectable signal. A wide range of commercial diagnostic kits rely on HRP. It is essential to ensure stability of HRP in the diagnostic kits in order to produce a reliable and reproducible signal and thus reduce the possibility of false results.

HRP is known to lose its activity gradually over time, especially at temperatures above refrigeration. The gradual loss of activity also complicates the production process, because stock solutions of HRP conjugates have to be prepared frequently and stored refrigerated. Formulations of HRP allowing storage at ambient temperature for extended periods of time, such as several months, would improve the production efficiency.

The objective of this development programme was to apply the ArestatT technology to improve the stability of HRP in liquid formulations

ArestatT solution

The ArestatT formulation technology specific for metal-containing proteins was employed to improve stability of HRP. More than 95% of HRP activity could be retained in the ArestatT formulation after 8 weeks whereas activity in the original HRP formulation dropped to <15% following the same treatment.