Serial ricinine levels in serum and urine after ricin intoxication.

Ricinine is an alkaloid present in the castor bean plant (Ricinus communis) that can be used as a biomarker for ricin poisoning. Serial ricinine levels are reported in the serum and urine of a patient suffering from intentional ricin intoxication. The patient was brought to the hospital 4 h after injection and oral intake of a castor bean extract, but died 38 h later, despite intensive medical care. Ricinine was isolated from the samples by solid-phase extraction and quantitatively determined by isotopic dilution liquid chromatography-mass spectrometry. The ricinine level in serum declined from 33 to 23 ng/mL between 10 and 29 h post-exposure. Three urine samples collected from 12 to 41 h after ricin intoxication showed ricinine concentrations in the range of 20-58 ng/mL. The creatinine corrected values (21-30 µg/g) indicated a concentration-time profile with a maximum ricinine level in urine between 12 and 29 h after exposure.