isonicotinic

from The Collaborative International Dictionary of English v.0.48

Isonicotinic \I`so*nic`o*tin"ic\, a. (Chem.)
   (a) Pertaining to, or derived from, isonicotine.
   (b) Pertaining to, or designating, an acid isomeric with
       nicotinic acid.
       [1913 Webster]