Teicoplanin‐Based Enantioselective, Potentiometric Membrane Electrodes for the Determination of R‐Baclofen in Pharmaceutical Formulations

Abstract

Two enantioselective, potentiometric membrane electrodes were proposed for the assay of R-baclofen. The electrodes were designed using a macrocyclic glycopeptide antibiotic, teicoplanin. Acetonitrile was added to the teicoplanin to design a modified teicoplanin-based electrode. The linear concentration ranges for the proposed enantioselective, membrane electrodes were 10 27 -10 24 mol/L for teicoplanin-based electrode and 10 26 -10 24 mol/L for the electrode based on teicoplanin modified with acetonitrile. The slopes of the electrodes were 60.0 mV/pR-baclofen and 57.2 mV/pR-baclofen for teicoplanin and teicoplanin modified with acetonitrile-based electrodes, respectively. The enantioselectivity was determined over S-baclofen. The proposed electrodes can be employed reliably for the assay of R-baclofen raw material and from its pharmaceutical formulation, Norton-Baclofen w tablets. The surfaces of the electrodes are stable and easily renewable by polishing on alumina paper.