Electrochemical determination of methocarbamol on a montmorillonite-Ca modified carbon paste electrode in formulation and human blood.

Utilizing the fascinating strong adsorptive ability, high chemical and mechanical stability properties of montmorillonite-calcium (MMT-Ca) clay, a MMT-Ca modified carbon paste electrode was developed for the sensitive determination of methocarbamol. Methocarbamol has been oxidized in buffered solutions at the developed MMT-Ca-modified CPE in a single 2-electron irreversible anodic peak. A simple and sensitive square-wave adsorptive anodic stripping voltammetric method was optimized for determination of methocarbamol in bulk form, pharmaceutical formulation and in spiked human serum using the developed modified CPE. This was carried out without the necessity for samples pretreatment and/or time-consuming liquid-liquid or solid-phase extraction steps prior to the analysis. The developed electrode exhibited an excellent sensitivity and selectivity towards methocarbamol even in the presence of 10(2)-10(4)-fold of its active ingredient "ibuprofen," common excipients, common metal ions or co-administrated drugs. Limits of detection of 3 x 10 (-9) and 1.2 x 10(-8) M and limits of quantitation of 1 x 10(-8), and 4 x 10(-8) M methocarbamol were achieved in the bulk form and in spiked human serum, respectively. Moreover, the developed method was successfully applied for determination of methocarbamol in human plasma of subjects following administration of an oral dose of Ibuflex tablets.