Co-crystallization of anti-inflammatory pharmaceutical contaminants and rare carboxylic acid–pyridine supramolecular synthon breakdown

Abstract

The reliability of supramolecular synthons in co-crystals involving naproxen and mefenamic acid is investigated. The carboxylic acid⋯pyridine synthon is exceptionally reliable; however, we observe synthon breakdown and a rare pyridyl dimer in a co-crystal with mefenamic acid. A Cambridge Structural Database survey supports the rarity of this motif in acid–bipyridine co-crystals.