Pyrene [4,5,9,10-14C]

Pyridin-2-yl-acetic acid [14C] methyl ester

Pyridine [2,6-14C] hydrochloride

Pyridine-2,4-dicarboxylic acid [2-carboxyl-14C]

3-Pyridinecarboxaldehyde [carbonyl-14C]

Pyridostigmine iodide [pyridine-N-methyl-14C]

Pyridoxine [methylene-3H]

N-(4-Methoxyphenyl)methyl-N',N'-dimethyl-N-(2-pyridinyl)-1,2-ethanediamine [3H]

Pyroglutamic acid, DL-[1-14C]

Pyroglutamic acid, L-[14C(U)]