Co-crystallisation of α,ω-dicarboxylic acids with nicotinamide and isonicotinamide

Pharmaceutical co-crystallisation is an alternative and potentially reliable method to manipulate physical properties of API’s via supramolecular synthesis. A number of binary co-crystals were synthesised using different solvents, different stoichiometric ratios (ratio of starting materials) and different methods of synthesis (solvent-mediated crystallisation, solvent-drop grinding and neat grinding), with a view to investigate solvent and stoichiometric effects on the materials formed. Selected α,ω-alkanedicarboxylic acids (HOOC-(CH₂)_n-COOH) were crystallised with nicotinamide for n = 0, 1, 2, 4, 5, 6, 7 and isonicotinamide for n = 5, 6, 7 yielding 12 new solid materials. The melting point of the starting materials and new products are determined and analysed, and the new crystalline materials characterised using NMR, FTIR, powder X-ray diffraction data (PXRD) and single X-ray diffraction data (SXRD). For azelaic acid : nicotinamide (1:1), structure solution was carried out using powder X-ray diffraction data and the direct space methods are applied through differential evolution (DE) approach. The crystal structure of adipic acid : nicotinamide (1:2) was solved using single crystal X-ray diffraction. The crystal structures of both, display strong O-H….N(pyridine), O-H^….O=C and N-H^….O=C intermolecular bonds. Other new materials formed were oxalic acid:nicotinamide (1:1 and 1:2), malonic acid : nicotinamide (1:1 and 1:2), succinic acid : nicotinamide (1:1), pimelic acid : nicotinamide (1:1), suberic acid : nicotinamide (1:1), azelaic acid : nicotinamide (1:1), pimelic acid : isonicotinamide (1:1), suberic acid : isonicotinamide (1:1 and 1:2) and azelaic acid : isonicotinamide (1:1), but these were not fully characterised by X-diffraction.

Name dc:type.qualificationname

m_rs

Level dc:type.qualificationlevel

m_rs

Grantor dc:publisher.institution

University of Birmingham

Year dc:date.issued

2010

Author dc:creator

• Voguri, Raja Sekhar

• QD Chemistry