APR Nov/Dec 2022 - 37

format for simultaneous removal of proteins and phospholipids from biological samples.
Unlike phospholipid removal products that use a hydrophobic retention mechanism,
the technology is based on zirconia (ZrO₂) coated onto the silica stationary phase. The
zirconium (Zr) atoms act as a Lewis acid (electron acceptor), having empty d orbitals,
while the phosphate moieties of phospholipids act as a strong Lewis base (electron
donor). This mechansim provides for strong interaction between the phospholipids and
the Zr atoms. The technology is capable of separating phospholipids from even highly
hydrophobic analytes.
A diverse list of challenging analytes
Recently, we have placed the same HybridSPE® sorbent we use in common SPE formats
into a Dispersive Pipette Extraction (DPX)
What if biologics
characterization
felt easier?
Trust our analytical products
and expertise in every stage of
your biologics development.
tip format. The HybridSPE®-DPX tips are
available in a variety of tip types for use with manual, semi-automated or fully automated
liquid handlers. In this case, the sorbent is allowed to disperse and mix freely within the
sample solution (Figure 1). Using it, applications have been developed for analysis of a
range of challenging analytes. These analytes include clenbuterol, warfarin, verapamil,
steroid hormones, omeprazole, digoxin, as well as antineoplastic, antidepressant,
antiarrhythmic and immunosuppressant drugs. A further example is segesterone
acetate (Nestorone®), a synthetic progestin for female and male contraception. The
compound was previously measured in serum by radioimmunoassay but had nonspecifi
c interferences which led to erroneous, false-positive levels being reported in
men. HybridSPE® DPX Tips allowed a sensitive LC-MS/MS assay for segesterone acetate
in human serum to be developed and validated for use in clinical and research studies.
FIGURE 1. Workfl ow for using HybridSPE®-DPX tips.
* Product characterization
* Method development
* Quality control
* Release
Visit us
SigmaAldrich.com/BiologicsQC
Condition via
apirating/dispensing
conditioning solution
Aspirating/dispensing
sample allows
HybridSPE®
retain phospholipids
Elute clean sample,
free of phospholipids
sorbent to
Condition
Bind
Elute
To fi nd out more about HybridSPE®-Phospholipid to
remove phospholipids from biological samples, visit
sigmaaldrich.com/hybridSPE
See applications in the MilliporeSigma chromatogram
database for which HybridSPE® technology was
successfully used: sigmaaldrich.com/hybridspeProtocol
© 2022 Merck KGaA, Darmstadt, Germany
and/or its affiliates. 40230 03/2022
www.americanpharmaceuticalreview.com |
| 37

http://www.SigmaAldrich.com/BiologicsQC http://www.sigmaaldrich.com/hybridSPE http://www.sigmaaldrich.com/hybridspeProtocol http://www.americanpharmaceuticalreview.com

APR Nov/Dec 2022

Table of Contents for the Digital Edition of APR Nov/Dec 2022