Biomaterial Database

A rapid, sensitive and specific radioimmunoassay for methotrexate. 1977

J W Paxton, and F J Rowell

A rapid, sensitive, radioimmunoassay for methotrexate has been developed using tritiated methotrexate and an antiserum raised in rabbits against the immunogen, bovine serum albumin containing 34 methotrexate residues per protein molecule. Separation of bound and free drug was attained using donkey anti-rabbit precipitating serum. The method can accurately measure as little as 50 fmol methotrexate in capillary blood samples and is not interfered with by vast excesses of natural folates nor citrovorum rescue factor. The method can handle 30 samples per day with the results available after 6 h. This makes it suitable for monitoring serum methotrexate levels after high dose therapy when a result is required within 24 h to provide helpful information regarding impending toxicity and the need for extended citrovorum rescue factor or maintenance of urinary pH.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008727	Methotrexate	An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of TETRAHYDROFOLATE DEHYDROGENASE and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA.	Amethopterin,Methotrexate Hydrate,Methotrexate Sodium,Methotrexate, (D)-Isomer,Methotrexate, (DL)-Isomer,Methotrexate, Dicesium Salt,Methotrexate, Disodium Salt,Methotrexate, Sodium Salt,Mexate,Dicesium Salt Methotrexate,Hydrate, Methotrexate,Sodium, Methotrexate
D008832	Microchemistry	The development and use of techniques and equipment to study or perform chemical reactions, with small quantities of materials, frequently less than a milligram or a milliliter.
D011863	Radioimmunoassay	Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.	Radioimmunoassays
D003429	Cross Reactions	Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.	Cross Reaction,Reaction, Cross,Reactions, Cross
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man