Abstract

In vitro blood-plasma partitioning demonstrated that the acyl glucuronide partitioned into the plasma sub-compartment of whole blood more favorably than the erythrocyte. This may partially explain the negative bias observed with DBS and suggest the need for a partitioning correction factor5. Literature has shown that a multispecific organic-anion transporter for glucuronides (MOAT4) exists in human erythrocytes9. Other literature reported that parent drug to metabolite ratios for morphine, morphine-3-glucuronide, and morphine-6-glucuronide were strongly influenced by hematocrit and water ratios.