SEPARATION AND DETERMINATION OF SORBITOL AND XYLITOL IN MULTICOMPONENT PHARMACEUTICAL FORMULATIONS BY CAPILLARY ISOTACHOPHORESIS

Pharmaceutically important polyhydric alcohols sorbitol (SO) and xylit ol (XY) are efficiently separated and determined by analytical capilla ry isotachophoresis (ITP) with conductometric detection. The on-column complex-formation equilibria between the polyols and boric acid are u tilized-the terminating berate ion acts as the complexing agent. The I TP operational system used consists of 10 mM HCl + 20 mM imidazole (LE , pH 7.0) and 20 mM boric acid (TE, pH 8.0). The effective mobilities of the berated SO and XY are 8.3 x 10(-9) m(2) V-1 s(-1) and 7.4 x 10( -9) m(2) V-1 s(-1), respectively. The ITP analysis is performed with t he driving and detection currents of 50 mu A (for 700 s) and 20 mu A, respectively. The calibration graphs are rectilinear in the range 25-2 50 mg l(-1) of SO and 50 to 500 mg l(-1) of XY. The method is applied to the simultaneous assay of SO and XY in three mass-produced multi-co mponent infusion solutions. Favourable values of the method validation parameters obtained confirm the suitability of the proposed ITP metho d for the quality control of pharmaceuticals. (C) 1998 Elsevier Scienc e B.V. All rights reserved.