According to the World Health Organization (WHO), heart disease is the number one cause of death worldwide. As a result, medication
for heart treatment is counted among the most frequently prescribed therapeutic classes. While most prescription drugs can
cause some adverse reaction in a patient, side effects of cardiovascular agents can be particularly hard to manage. There
may only be a subtle distinction between a therapeutic dose and a life-threatening one. Therefore, efficient drug monitoring
is an important tool in enhancement of drug efficacy and reduction of the risk of toxic effects resulting in a balanced treatment.
With the advance of highly sensitive and fast liquid chromatography tandem mass spectrometry (LC–MS–MS) instruments, triple
quadrupole technology has found its way into clinical drug monitoring. It is the preferred technique for an increasing number
of applications in the clinical sector, demanding fast and efficient development of new LC–MS–MS methods. Fast ultrahigh-pressure
liquid chromatography (UHPLC) screening using Shimadzu's specialized scouting software in combination with automated MS optimization
for multiple reaction monitoring (MRM) parameters are the perfect platform for rapid generation of dedicated analytical procedures.
For UHPLC method scouting, a Shimadzu Nexera X2 Method Scouting System was used, consisting of two quaternary solvent pumps
(LC-30AD), an autosampler (Sil-30AC), and a column oven (CTO-20AC) including a six-column switching valve (FCV-34AH). The
system was also equipped with a Shimadzu LCMS-8040 triple quadrupole mass spectrometer via an electrospray ionization (ESI)
Figure 1: Structures of cardiovascular drugs.
The method scouting system enables screening of a maximum of six HPLC columns with up to 16 different eluents. The different
mobile and stationary phases used for method scouting for the separation of eight cardiovascular drugs are displayed in Table
Table 1: Mobile and stationary phases used in method scouting.
For automated generation of an optimized MRM method the first step is selection of the precursor ion, followed by mass-to-charge
ratio (m/z) adjustment of the precursor. The collision energy is optimized for the most abundant fragments and finally the fragment
m/z is adjusted. These optimization steps were performed via flow injection analysis, each taking 30 s (Figure 2).
Figure 2: Automated multiple reaction monitoring (MRM) optimization on the LCMS 8040.
Method scouting was performed in a 30 h sequence using 5 min and 2 min gradient runs with varying gradient slope and all
possible combinations of aqueous and organic mobile phases on the six columns specified in Table 1.