Application of miniaturized immunoassays to discovery pharmacokinetic bioanalysis

IntroductionPharmacokinetic properties of biotherapeutics are an important aspect of preclinical drug development. The lead identification and optimization space is characterized by aggressive timelines, large sample numbers, a variety of species and matrices, and limited reagent and sample volumes all of which represent challenges for traditional microtiter plate assays. Since the Gyrolab immunoassay platform can accommodate small sample volumes and automated assay processing, we evaluated the workstation as an alternative to the plate-based assays.MethodsThree representative example assays — a generic anti-human IgG, a target specific and an anti-drug capture assay — were investigated in detail for accuracy and precision performance and their application to bioanalytical support for preclinical pharmacokinetic studies. Different animal matrices were tested in the assays and during study support.ResultsGyrolab procedures could be closely modeled after regular microtiter plate assays. The small reagent volumes necessary for Gyrolab allowed studying serial bleeds of transgenic mice with only 10 μL of blood sample. During development and during study support, the Gyrolab performance was similar to what can be expected from plate-based systems with accuracy and precision within 100 ± 20% or less.DiscussionOverall, the technology was well suited to support quantitation of biotherapeutics using small volume samples from different preclinical species. Limited operator involvement for assay processing allowed for reduced staffing and training. However, high instrument costs and a single source of reagent supplies represent risks when moving assays further into long-term applications such as clinical studies. Despite interest in the bioanalytical field, this is the first detailed investigation of bioanalytical applications of Gyrolab in pharmacokinetic studies.