Macrocycle versus podant-type neutral ionophore in potentiometric detection of mucolytic agents following separation by various HPLC modes.

G. BAZYLAK; L.J.NAGELS; M. E. MONGE

CHROMATOGRAPHIA

VIEWEG

Año: 2003 vol. 57 p. 757 - 765

0009-5893

Potentiometric detection of lipophilic drugs such as clenbuterol, ambroxol and bromhexine in standard-bore cyano and narrow-bore hybrid, reversed-phase HPLC systems was developed to enable specific determination of these mucolytic agents in some marketed oral-formulations. The macrocycle and podant-type, neutral ionophores, respectively: hexakis(2,3,6-tri-O-octyl)-?-cyclodextrin (CDX) and N,N,N′,N′-tetracyclohexyl-oxybis(o-phenyleneoxy)diacetamide (TOPA), were used to construct PVC-based, liquid membrane electrodes. In acidic aqueous-acetonitrile, mobile phases both ionophores improved the sensitivity of these electrodes for mucolytic agents when compared to single-wavelength UV detection - as well as with the ionophore-free based electrode. In the case of bromhexine, indicating highest lipophilicity (logP 6.40), detection limits of 2.6 × 10-10 and 1.4 × -10 M (injected concentration) were achieved with a signal-to-noise (S/N) ratio of 3 with the TOPA-modified, liquid membrane electrode in the variaus RP-HPLC systems. The results of procedures validated for simultaneous potentiometric determination of clenbuterol and ambroxol in tablets marketed in different countries are also presented.