High-throughput determination of ultra-low concentrations of LAG078, a lipid modulator, in human plasma

A high throughput method with ultra-low level quantification limit (10 pg/ml) was developed and validated for the quantitative determination of LAG078, a lipid modulator, in human plasma to support clinical studies employing low doses of the compound. The method consisted of reverse phase chromatographic separation of the analyte from plasma extract followed by electrospray ionization (ESI) in the negative ion mode and tandem mass spectrometry in the multiple reaction monitoring mode (MRM). Extraction was performed using a combination of protein precipitation and liquid-liquid extraction in the 96-well plate format to increase the throughput of the method. Optimised chromatographic separation in a short and high-resolution column (50 mm x 2.0 mm i.d., 3 microm particle size) coupled with MRM mode of detection yielded clean chromatograms with minimal signal suppression. The standard curve was linear (r=0.996) within the concentration range of 0.01 (lower limit of quantification) to 50 ng/ml using 0.5 ml of human plasma. The accuracy of the method varied from 95-101% with a precision (CV) of 5.29-13.2% over the concentration range. The method was simple and rapid.