Publication / Source: Bioanalysis 3(11)
Authors: Taillon MP, Furtado M, Garofolo F
Marie-Pierre Taillon holds a Bachelor of Science in Biochemistry. She is a senior scientist in method development at Algorithme Pharma, a CRO located in Laval, Canada. She has been working in the bioanalysis industry for the past 11 years where she became an expert in method development, especially in the LC–MS/MS field. Her experiences have led her to conduct robust and effective method development of bioanalytical assays. Marie-Pierre has acquired over the years an expertise with the ‘-limus’ compounds (e.g., tacrolimus, sirolimus and everolimus) and other complex molecules.
The quantification of tacrolimus in human whole blood was developed by LC–MS/MS for a range of 50.0 to 50,000.0 pg/ml. Different challenges were faced during method development due to ion-suppression, lack of sensitivity and low recovery. The optimization of the extraction procedure played a crucial role as tacrolimus had to be isolated from red blood cells, to which it is strongly bound. Another particular challenge arose from the freeze–thaw stability where the extracted samples from fresh blood always showed a lower recovery. Finally, matrix effect was observed in some matrices over time, which resulted in a failed long-term stability in whole blood. In order to resolve the matrix effect issue, the sample procedure had to be improved. The final assay showed good recovery, low matrix effect, linearity, blood stability and good precision and accuracy.