  Sulfated polysaccharides constitute a large and complex group of
macromolecules which possess a wide range of important biological properties.
Many of them hold promise as new therapeutics, but determination of their blood
levels during pharmacokinetic studies can be challenging. Heparin Red, a
commercial mix-and-read fluorescence assay, has recently emerged as a tool in
clinical drug development and pharmacokinetic analysis for the quantification
of sulfated polysaccharides in human plasma. The present study describes the
application of Heparin Red to the detection of heparin, a highly sulfated
polysaccharide, and fucoidan, a less sulfated polysaccharide, in spiked mouse
and rat plasmas. While the standard assay protocol for human plasma matrix gave
less satisfactory results, a modified protocol was developed that provides
within a detection range 0 to 10 micrograms per mL better limits of
quantification, 1.1 to 2.3 micrograms per mL for heparin, and 1.7 to 3.4
micrograms per mL for fucoidan. The required plasma sample volume of only 20
microliters is advantegous in particular when blood samples need to be
collected from mice. Our results suggest that Heparin Red is a promising tool
for the preclinical evaluation of sulfated polysaccharides with varying
sulfation degrees in mouse and rat models.
