Highly sensitive and selective determination of methylergometrine maleate using carbon nanofibers/silver nanoparticles composite modified carbon paste electrode.

A highly sensitive and selective voltammetric method for determination of Methylergometrine maleate (MM) in pharmaceutical formulations, urine and blood serum samples has been developed based on enhanced electrochemical response of MM at carbon nanofibers and silver nanoparticles modified carbon paste electrode (CNF-AgNP-CPE). The electrode material was characterized by various techniques viz., X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic response of MM at CNF-AgNP-CPE was studied by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Under optimized conditions, the proposed sensor exhibits excellent electrochemical response towards MM. The DPV study shows greatly enhanced electrochemical signal for MM at CNF-AgNP-CPE lending high sensitivity to the proposed sensor for MM detection. The peak (Ip) current for MM is found to be rectilinear in the range 4.0×10(-8)-2.0×10(-5)M with a detection limit of 7.1×10(-9)M using DPV. The feasibility of the proposed sensor in analytical applications was investigated by conducting experiments on commercial pharmaceutical formulations, human urine and blood serum samples, which yielded satisfactory recoveries of MM. The proposed electrochemical sensor offers high sensitivity, selectivity, reproducibility and practical utility. We recommend it as an authentic and productive electrochemical sensor for successful determination of MM.

Methylergometrine (methylergonovine) concentrations in the human plasma and urine.

There were no significant differeneces in the radioimmunologically determined plasma concentrations of methylergometrine, nor in its 32-hour cumulative urinary excretion after a sinlge 0.250-mg p.o. dose of Methergin (Sandoz) or Myomergin (Leiras). Peak plasma concentrations were obtained as early as 0.5 hours after the drug administration. Approximately 3% of the 0.250-mg p.o. dose was excreted in the urine during a period of 32 hours. In two subjects, after a single 0.20-mg i.v. injection, the beta phase half-life in the plasma was 1.9 hours. From the ratio of the area under the plasma curve after p.o. and i.v. administration in these two subjects, it was estimated that 64% and 63% of the p.o. dose reached the systemic circulation. No cumulation in the plasma was observed after repeated p.o. doses of 0.125 mg of methylergometrine given thrice daily to the two subjects.