Abstract:
The separation by reverse polarity capillary zone electrophoresis of the therapeutically
developed sodium salt of Pentosan Polysulfate was optimised through the analysis of
response surface methodologies, modeled using a central composite design. The optimisation
investigated injection pressure, injection time and voltage and the effect of the conditions on
retention times, peak areas, separation efficiency and the method sensitivity. The overall goal
was to develop the most sensitive results with no decrease in separation efficiency. The
following results were obtained: (1) retention times generally decreased as injection pressure,
injection time and voltage increased, injection time having the least effect; (2) as expected
peak areas increased as injection pressure and injection time increased but decreased as
voltage increased; (3) separation efficiencies generally increased as injection pressure and
injection time decreased, with voltage having almost no effect. For the optimum condition,
the sample was introduced at the inlet vial at the cathode hydrodynamically, at optimal
setting of 44 s at 35 mbar. The optimal voltage was -20 kV. In comparison with other
methods, the optimum showed increased sensitivity, resolution and separation efficiency.
Repeatability studies were performed on the optimum parameter conditions. Relative
standard deviation values obtained were between 0.9 and 5.4%.
