TY - JOUR T1 - RADIOIMMUNOASSAY FOR HEPATIC N-DEMETHYLATION OF METHARBITAL <em>IN VITRO</em> JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 550 LP - 556 VL - 189 IS - 2 AU - Edward J. Flynn AU - Sydney Spector Y1 - 1974/05/01 UR - http://jpet.aspetjournals.org/content/189/2/550.abstract N2 - A sensitive assay procedure for determining hepatic N-demethylation of metharbital is presented. The assay is based on the ability of an antibody to differentiate between the parent drug (metharbital) and its metabolite (barbital). The method is sensitive, so that less than 1 nmol of barbital formed per incubation flask can be measured. In addition to sensitivity, the assay requires no organic extraction procedures and, therefore, offers advantages in terms of speed, ease of assay and capability for using automated techniques. The method described should be applicable to a variety of enzyme reactions after production of an antibody which binds the product of the reaction. Once this is accomplished the method is extremely useful where current methodology suffers due to lack of sensitivity, availability of only small amounts of enzyme or time-consuming organic extraction procedures. © 1974 by The Williams &amp; Wilkins Co. ER -