Material Balance Studies on Cigarettes Containing 3-Phenyl-5-methyl-1,2,4oxadiazole

Material balance studies were performed on 85 mm machine-made cigarettes containing 1.5 % unlabelled PMO [3-phenyl-5-methyl-1,2,4-oxadiazole], which were smoked under standard conditions to a 23 mm butt length. Using standard analytical techniques, relative distributions of PMO of approximately 28 % for mainstream, 22 % for sidestream, and 27 % for butt were obtained, with an overall recovery of unchanged PMO of 75-80 %. Radiocarbon labeled PMO [5-14C] cigarettes were prepared manually (70 mm, 2 % PMO) and smoked under standard conditions to a 20 mm butt length. Four smoking runs gave statistically valid data accounting for 95.99 ± 0.58 % of the original label. Measurements of the radioactivity were made by liquid scintillation counting of the various fractions. The mainstream smoke passing through a Cambridge filter pad contained less than one percent of the label as carbon dioxide, and no volatile organic compounds. The PMO undergoing decomposition gave rise to products found almost entirely in the sidestream.