(M1130-06-37) Bioanalytical Assessments of a Novel Approach to Overcome Microsampling Challenges in Rodent Studies

Purpose: Blood volume limitation is a widespread challenge in rodent studies. Several microsampling technologies, such as VAMS or Microvette, have been investigated to mitigate the challenge; however, at the preclinical stage of drug development, the adoption of microsampling technologies has been slow. The common hurdles are delicate sample handling, reduced pipetting accuracy at volumes of less than 10 μL, and insufficient sample volume/aliquots for incurred sample reanalysis. With the potential to overcome these hurdles, Microsampling Wings, a novel microsampling device, was assessed. A liquid chromatography with tandem mass spectrometry (LC–MS/MS) method utilizing the Microsampling Wings device was developed and implemented in discovery rodent studies. The performance of the microsampling device was evaluated and compared against the conventional venous blood collection. The preliminary assessments demonstrated a great potential of this novel Microsampling Wing device in support of drug development in small rodents.

Methods: A LC-MS/MS method was developed in SRM mode using a Shimadzu LC30 AD series UHPLC and SCIEX Triple Quad™ 5500 mass spectrometer for measuring Dexamethasone in rodent plasma. Micro-sampling device MSW2TM (Shimadzu Corporation) was used for blood collection. The plasma samples collected were centrifuged out from the wing device and precipitated in 96-well plates by acetonitrile added with IS. The supernatant was then transferred and analyzed by LC-MS/MS. The assay range established was 10-10,000 ng/mL for quantitation.

Results: Microsampling wings were able to collect microsamples with flexible aliquots (four 1.4 μL aliquots or two 2.8 μL aliquots) precisely. We utilized the microsampling wings in a rat study in which the blood samples were collected and centrifuged for plasma. The plasma aliquots were easily snapped off from the device and then centrifuged to expel the plasma out of the microchannels. During the initial investigation, the plasma volumes out of the microsamples were compared with the pipetted volume, showing great consistency in volume. For bioanalysis, the LC-MS/MS method was qualified to quantify Dexamethasone in rat plasma from the device. Good assay accuracy and precision were achieved for all analytical QC samples at the four concentration levels of 30, 350, 4000, and 8000 ng/mL. The intra-day and inter-day precision results were ≤11.1% and ≤7.9%, respectively; the intra-day and inter-day accuracy results were -3.4 to 5.8% and -3.3 to 4.9%, respectively. The pharmacokinetics (PK) parameters will be further calculated and concordance between the microsampling wing collection and conventional approach will be reported in the final poster.

Conclusion: The microsampling wing is a novel device that was easy to use for blood collection. Flexible number of aliquots with accurate volume could be directly collected for reanalysis without micro-pipetting. Based on the preliminary results, reproducibility and comparability were demonstrated. The LC-MS/MS assay combined with the wing device showed great accuracy and precision. The Microsampling Wing has shown an exciting potential as a solution to the challenges that are not entirely overcome to date

Acknowledgements: We would like to thank Regulated Bioanalysis Operation Group for management and logistics support; Also thank Shimadzu for the collaboration and discussion on the microsampling wing devices.