DETERMINATION OF METHYLERGOMETRINE AND DIHYDROERGOTOXINE IN BIOLOGICAL FLUIDS

Abstract

New hapten-carrier conjugates were prepared from 9, 10-dihydro-N-[1-(hydroxymethyl) propyl]-6-methylergoline-8-carboxamide 1-hemisuccinate (dihydromethylergometrine hemisuccinate) by coupling with bovine serum albumin employing the mixed anhydride technique. The specificity of anti-dihydromethylergometrine antiserum elicited in the rabbits by immunization with this antigen was tested by cross-reaction studies with methylergometrine, dihydroergotoxine, dihydroergocristine and dihydroergotamine employing [9, 10-³H]-dihydromethylergometrine and [9, 10-³H]-dihydroergocryptine in the radioimmunoassay procedure. These cross reactivities were observed 100% for methylergometrine, 48.3% for dihydroergotamine, 16.6% for dihydroergotoxine and 6.6% for dihydroergocristine using labeled dihydromethylergometrine. When labeled dihydroergocryptine was the results were 18.3%, 112.1%, 100% and 63.8%, respectively. Methylergometrine concentrations in the postpartal plasma and milk at 2 hr after oral administration of methylergometrine maleate (0.75 mg) to woman were 5.1 ng/ml and 1.3 ng/ml, respectively. Dihydroergotoxine concentrations in the rabbit sera after oral administration of dihydroergotoxine methanesulfonate (4 mg) were studied. The assay was satisfactory to permit the measurement of ergot alkaloid levels in the biological fluids.