Radioimmunoassay for bupropion in human plasma: comparison of tritiated and iodinated radioligands.
We evaluated the potential usefulness of 125I-labeled p-hydroxybupropion in a direct radioimmunoassay for bupropion in human plasma as compared with a currently used [3H]bupropion dextran-coated charcoal method. In both radioimmunoassay methods succinoylpropylbupropion antiserum was used that was highly specific for unchanged drug, cross reactivities with known bupropion metabolites being less than 0.3%. However, the use of 125I-labeled p-hydroxybupropion afforded greater sensitivity (0.3 microgram/L vs 0.6 microgram/L with [3H]bupropion) and was readily adaptable to the more convenient polyethylene glycol separation method. Between-assay CVs were 3.8 to 12.2% (mean 7.6%) with the 125I-based radioimmunoassay and 5.1 to 11.5% (mean 7.5%) with the 3H-based assay. Agreement between the two radioimmunoassay determinations of buproprion in human plasma samples collected over a 60-h period after oral drug administration was excellent (slope = 1.086, r = 0.989). We find the 125I-based assay a convenient and suitable alternative to the [3H]bupropion assay in pharmacokinetic studies in humans.
D000328:Adult; D000928:Antidepressive Agents; D016642:Bupropion; D003429:Cross Reactions; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D011092:Polyethylene Glycols; D011427:Propiophenones / Q000097:blood*; D011863:Radioimmunoassay / Q000379:methods; D013997:Time Factors; D014316:Tritium
D000928:Antidepressive Agents; D007457:Iodine Radioisotopes; D011427:Propiophenones; D016642:Bupropion; D014316:Tritium; D011092:Polyethylene Glycols