Novel Sample Processing Approach to Overcome Formulation Effects on LC-MS/MS Bioanalytical Results
Challenge:
- Plasma LC-MS/MS analysis for the active sphingolipid after IV administration of a sphingolipid liposomal formulation showed very short half-life when compared to a previous study done with radiolabeled lipid formulation.
Solution:
- The initial plasma bioanalytical method using ACN protein precipitation could successfully quantify sphingolipid after spiking liposome formulation in-vitro in plasma.
- When applied to study samples, measured concentrations at early time points (5 to 15 min post dose) were similar to those seen in a radiolabel liposome study. However, the terminal half-life was substantially smaller with the LC-MS/MS data.
- Detailed experiments including variety of sample processing techniques revealed that sample preparation plays a significant role in the actual recovery of analytes from in-vivo samples.
- When the same study samples were prepared under unusually strong conditions (45C for 8 h in an oven) to de-aggregate the constituent lipids in the liposome, the PK of the sphingolipid was similar to that seen in the radiolabeled study. This may result from complexation of the liposomal lipid after dosing in vivo.
This case study was presented as poster in Applied Pharmaceutical Analysis (APA) India 2015 and was awarded a prize.