Development of affinity polymeric particles for the removal of 4-dimethylaminopyridine (DMAP) from active pharmaceutical ingredient crude streams using a green technology

Polymeric particles with affinity for 4-dimethylaminipyridine (DMAP) were developed by molecular imprinting using supercritical carbon dioxide (scCO₂) technology, for cleanup of this potentially genotoxic impurity from crude mixtures of Active Pharmaceutical Ingredients (APIs). DMAP-molecularly imprinted polymer (DMAP-MIP) and the respective control, the non-molecularly imprinted polymer (NIP) were produced by free radical polymerization using methacrylic acid as monomer, ethylene glycol dimethacrylate as crosslinker and AIBN as free-radical initiator in scCO₂. The materials were obtained in high yield and were characterized chemically, physically and morphologically. Their extraction efficiency was evaluated by dynamic binding experiments using two solutions: i) a solution containing 104 ppm DMAP solution; ii) model pharmaceutical mixture containing 104 ppm of DMAP and 1018 ppm of Mometasone furoate (API). Particles were able to remove 18.3 µmol DMAP/g polymer from a 104 ppm DMAP solution (i) and 1004.6 µmol DMAP/g API (ii). In addition, high recoveries of both DMAP and API were obtained, above 99%.