A Non-radiometric Approach to Determine Tissue Vascular Blood Volume in Biodistribution Studies

Area of Science:

• Pharmacokinetics and Drug Development
• Biomedical Engineering
• Analytical Chemistry

Background:

• Accurate quantification of tissue drug exposure in biodistribution studies is crucial.
• Traditional methods like perfusion and hemoglobin measurement for residual blood are unreliable and introduce variability.
• Non-radiometric, reproducible methods are needed to improve the accuracy of biodistribution studies.

Purpose of the Study:

• To develop and validate a non-radiometric method for measuring residual blood in tissues.
• To overcome the limitations of perfusion and hemoglobin-based techniques in biodistribution studies.
• To enable accurate correction of tissue drug exposure data by accounting for vascular blood volume.

Main Methods:

• Animals were administered a Residual Blood Determinant Reagent (RBDR) intravenously prior to tissue harvesting.
• RBDR levels were quantified in whole blood homogenate and tissue lysates.
• Vascular Blood Volume (VBV) was calculated using RBDR levels to correct tissue drug exposure.

Main Results:

• The perfusion method was found to be ineffective and introduced variability.
• Hemoglobin measurement as a biomarker for residual blood was unreliable.
• The RBDR method provided vascular blood volume measurements comparable to established radiometric techniques.
• Tissue drug exposures were successfully corrected using RBDR-derived VBV.

Conclusions:

• The developed RBDR method is a reliable and non-radiometric alternative for determining residual blood in tissues.
• This method enhances the accuracy and reproducibility of biodistribution studies.
• Accurate VBV determination using RBDR allows for precise correction of tissue drug exposure, improving pharmacokinetic analysis.