Ultra-sensitive quantification of intact insulin lispro in rat plasma


Featuring SCIEX Triple Quad™ 7500 LC-MS/MS System – QTRAP® Ready, powered by SCIEX OS Software

Lei Xiong1 , Ian Moore2
1SCIEX, USA; 2SCIEX, Canada

Abstract


Insulin analogs are altered forms of natural insulin that offer options for insulin replacement strategies with similar or improved actions for glycemic control. Among them are prandial insulin analogs, such as insulin lispro, aspart and glulisine, which tend to be more readily absorbed and act faster than human insulin (Figure 1). It is vital to study the pharmacokinetic and pharmacodynamic profiles of insulin analogs. However, developing sensitive LC-MS methods to quantify them in matrices remains challenging for multiple reasons: 1) the low ionization and CID fragmentation efficiency related to the high molecular weights, 2) low concentrations in matrices, 3) endogenous inferences from natural insulin.
In this technical note, a sensitive LC-MRM method was developed for the quantification of intact insulin lispro in rat plasma using the SCIEX Triple Quad 7500 LC-MS/MS System – QTRAP Ready. The OptiFlow® Pro Ion Source, together with the D Jet™ Ion Guide, offers significantly improved sensitivity for intact insulin analogues. It improves desolvation and focusing to improve instrument sensitivity and thus MRM performance. Insulin lispro was quantified at 0.1 ng/mL in rat plasma without analyte enrichment, with outstanding reproducibility, accuracy and linearity. 

RUO-MKT-02-11884-A1

Figure 1. The amino acid sequences of insulin lispro and human insulin. The sequence difference is labeled in green.

Key features of cyclic peptide quantification workflows 
 

  • Enhanced sensitivity of the SCIEX Triple Quad 7500 LCMS/MS System – QTRAP Ready through the introduction of key hardware features that provide significant gains in the generation, capture and transmission of ions1 : the OptiFlow Pro Ion Source with E Lens™ Technology combined with the D Jet Ion Guide

  • Simple sample preparation strategy, requiring no enrichment step

  • Robust quantification of insulin lispro at 0.1 ng/mL in rat plasma

  • High reproducibility, precision and accuracy across the calibration curve, with excellent linearity

  • A 4-fold improvement in S/N was observed when compared to the performance of the SCIEX Triple Quad™ 6500+ LCMS/MS System

  • SCIEX OS Software—a single, compliant-ready platform for acquisition, processing and data management, that is customizable and easy to use