Related Experiment Videos
Blood distribution of rapamycin
R Yatscoff1, D LeGatt, R Keenan
1Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada.
Transplantation
|November 1, 1993
Summary
This study investigated rapamycin (RAPA) distribution in human blood, finding it primarily binds to red blood cells (RBCs). Whole blood is recommended for RAPA analysis due to higher drug concentrations compared to plasma.
Area of Science:
- Pharmacology
- Clinical Chemistry
Background:
- Rapamycin (RAPA) is a crucial immunosuppressive drug.
- Monitoring RAPA blood concentrations is vital but its distribution is poorly understood.
- Understanding RAPA distribution impacts analytical method development.
Purpose of the Study:
- To investigate the distribution of rapamycin (RAPA) in human whole blood.
- To determine the impact of temperature and concentration on RAPA distribution.
- To identify the optimal biological matrix for RAPA analysis.
Main Methods:
- Human whole blood spiked with 3H-RAPA and varying RAPA concentrations (5-100 µg/L).
- Incubation at 37°C for 0-60 min, followed by cell separation.
- Scintillation counting to determine drug levels in plasma and red blood cell (RBC) fractions.
Main Results:
- RAPA predominantly distributes to RBCs (94.5%), with minimal amounts in plasma (3.1%), lymphocytes (1.01%), and granulocytes (1.0%).
- The plasma to whole blood ratio was low (0.09 ± 0.016).
- RAPA distribution showed no dependence on temperature or concentration within the tested range.
Conclusions:
- Rapamycin exhibits significant binding to red blood cells.
- The unbound fraction of RAPA in plasma is low (2.5%).
- Whole blood is the preferred matrix for RAPA analysis due to higher drug recovery.