Cetylpyridinium chloride, fractionation

After fractionation with cetylpyridinium chloride, the acidic heteropolysaccharide of Aureobasidium (Pullularia) pullulans contains D-mannose, D-galactose, D-glucose, and D-glucuronic acid in the ratios of 43 35 10 12. It has a main chain of (1— 6)-linked a-D-mannopyrano-syl units substituted as in structure158 38. 

As just stated, the L3 phase resembles structurally a bicontinuous microemulsion, which makes it interesting to compare their rheological properties. Viscosity measurements on an L3 phase [in the system cetylpyridinium chloride-hexanol-brine (0.2 M NaCl)] showed Newtonian flow behavior for the range of shear rates of 0.1-100 s" [113]. The viscosity of this highly interconnected, spongelike system is always very low and close to the solvent viscosity, even for a volume fraction of 0.2 it is less than 10 mPa s. (Similar viscosity values have been observed in the L3 phase of the system tetradecyldimethylamine oxide-hexanol-water [114].) It increases linearly with the volume fraction of the amphiphilic material, where it is interesting to note that extrapolation to zero concentration does not yield the solvent viscosity but a value about three times as high. A similar value for the extrapolated viscosity was also reported more recently for another L3 phase (in the system SDS pentanol-dodecane-water [115]), and it seems that this enhanced viscosity is a universal property connected to the structure of the L3 phase. 

The products obtained from fluids are generally free from other acidic polysaccharides.Those obtained from tissues contain sulfated polysaccharides and can be purified through precipitation with p nidine and ammonium sulfate , or by fractionation with cetylpyridinium chloride . 

The most convenient method of preparation of heparan sulfate uses a side-fraction in the preparation of commercial heparin. Fractionation with cetylpyridinium chloride, in presence of sodium chloride, afforded substances References p. aps... 

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