Abstract
Therapeutic proteins have exhibited promising clinical applications in the diagnosis and treatment of some diseases. Prior to the detection of analytes using enzyme-linked immunosorbent assay, biological samples of therapeutic proteins are conventionally frozen at temperatures ranging from - 20 to - 80 °C to increase the stability of analytes. However, therapeutic proteins destabilization and aggregation may occur during the frozen storage or the freeze-thawing step. In this work, an effective method was proposed to freeze-dry therapeutic protein samples to allow subsequent storage or transport of samples without freezing them. This new method was validated with quality control samples of adalimumab and etanercept, and it was also used in the bioanalysis of adalimumab and etanercept in pharmacokinetic (PK) studies. Adalimumab and etanercept were stable for 14 days at 4 °C after being prepared and stored using the new method, with detection that was accurate and repeatable. Studies of adalimumab and etanercept in animals and humans showed that the PK parameters of the analytes stored with the new method were consistent with those of analytes stored using the conventional method. This effective method will be attractive for facilitating the storage and transport of plasma samples containing therapeutic proteins.