title: Radioimmunoassay for etoposide and teniposide.
abstract: A radioimmunoassay for VP-16 or VM-26 was developed by using tritiated ligand and antisera produced from rabbits immunized with succinyl-VP-16 bovine serum albumin conjugates. Separate determinations of VP-16 and its hydroxy acid, a metabolite which cross-reacted with the VP-16 antisera, could be accomplished by extracting samples with chloroform in which the metabolite was insoluble. The assay was reproducible and sensitive. Extracted standard curves were linear from 0.025 to 5 micrograms for VP-16 and 0.1 to 10 micrograms for the hydroxy acid per 0.5 ml assay mixture. Fifty percent inhibition of binding was achieved at 0.066 and 0.55 microgram for VP-16 or VM-26 and the metabolite, respectively. Preliminary disposition studies in mice and dog, and human urinary excretion support the application of the assay in pharmacologic studies.
mesh_terms: D000818:Animals; D000915:Antibody Affinity; D003429:Cross Reactions; D004285:Dogs; D005047:Etoposide / Q000032:analysis* / Q000097:blood; D006801:Humans; D008099:Liver / Q000378:metabolism; D008657:Metabolic Clearance Rate; D051379:Mice; D011034:Podophyllotoxin / Q000031:analogs & derivatives*; D011817:Rabbits; D011863:Radioimmunoassay / Q000379:methods; D013713:Teniposide / Q000032:analysis* / Q000097:blood
chemical_list: D005047:Etoposide; D013713:Teniposide; D011034:Podophyllotoxin