Abstract: A radioimmunoassay for physostigmine in biological fluids. The method disclosed can detect 100 pg of physostigmine per ml of biological fluid using 0.1 ml of biological fluid. The antibody used in this method can be raised from an antigen produced by either or two methods--diazotizing para-aminobenzoic acid and reacting the diazotized material with physostigmine to form a physostigmine-hapten solution, which is then reacted with bovine serum albumin or by using a Mannich reaction to directly conjugate physostigmine to bovine serum albumin. The antibody used in the disclosed method has a cross-reactivity with the major metabolites of physostigmine of less than 1%.

Abstract: A sensitive and specific radioimmunoassay is developed for L-hyoscyamine ulting from atropine administration with which a concentration as low as 25 pg/ml using 0.1 ml of sample can be measured without the need for extraction. Specificity studies indicate that an antibody according to this invention has high specific recognition of L-hyoscyamine with only about 37% cross reaction with the D-hyoscyamine enantiomer of atropine. The antibody is produced from an immunogen having conjugated at least 42 and preferably 45 L-hyoscyamine-p-aminobenzoic acid haptenic molecules per molecule of bovine serum albumin. An antibody according to this invention can be used with a dilution titer as high as 1:2000.