April 04, 2013 -- LC-MS is a technology that has emerged as a high performance alternative to ligand binding assays for molecules such as Insulin and Exenatide.
When using ligand binding assays, cross-reactivity can be a considerable challenge for accurate quantification of human insulin and insulin analog formulations. For this reason, assay development of insulin (human and analogs) and C-peptide using LC-MS, is quickly becoming the industry standard. To generate pharmacokinetic profiles using LC-MS, the targeted LLOQs for C-peptide and total insulin are approximately 0.5 ng/mL and 0.1 ng/mL. To quantitate insulin and C-peptide and achieve the LLOQ required, samples may be concentrated using specific and selective extraction process. If a lower LLOQ is needed, an enzymatic digestion (using trypsin) of insulin and C-peptide to their signature peptides, is employed. To further increase insulin sensitivity, the strategy of reducing peptide disulfide bonds can also be utilized.
Algorithme Pharma has developed a high performance bioanalytical method for exenatide with an analytical range of 10 pg/mL to 2000 pg/mL. This LLOQ has been achieved using a unique and sensitive tryptic digest peptide, which demonstrates less charge state distribution and a clearer CID pattern than intact exenatide. For the once-weekly exenatide administration formulation, we are working towards decreasing the LLOQ to 2 pg/mL.
We will be hosting several presentations on large molecule quantification by LC-MS at the following meetings: 2013 WRIB (Workshop on Recent Issues in Bioanalysis), NBC (AAPS National Biotechnology) and ASMS (American Society of Mass Spectrometry).
Algorithme Pharma has extensive expertise in large molecule quantification by LC-MS. For additional information, please contact us at firstname.lastname@example.org.