Pawanpreet Singh
University Institute of Pharmaceutical Sciences, India
Title: Solid state analytical techniques to characterize cocrystals: Ciprofloxacin–hippuric acid co-crystal
Biography
Biography: Pawanpreet Singh
Abstract
Co-crystals are crystalline single phase materials composed of two or more different molecular and/or ionic compounds generally in a stoichiometric ratio which are neither solvates nor simple salts. They are of interest to both academic research as well as industry as they represent the opportunity to access new solid forms with modified physical properties including dissolution rate, physical stability and altered pharmacokinetic profile of the API subjected for co-crystallization. The present work represents Ciprofloxacin-Hippuric acid cocrystal which was prepared by solvent assisted grinding method. It was primarily characterized by FTIR showing shift in –COOH stretch at 3264.1 cm-1 in cocrystal as compared to 3405.2 and 3343.9 cm-1 in drug and coformer respectively. The C-N stretch also shifted from 1380 cm-1 to 1385.2 cm-1. The cocrystal was then confirmed by Differential scanning calorimetry showing single melting endothermic transition at 218.9oC irrespective of both components showing formation of new stable phase. XRPD pattern of cocrystal shows disappearance of two major peaks at 14.7 and 24.9o 2θ while another major peak shows drastic shift from 25.5 to 19.5o 2θ. Fortunately, the development of XRPD equipment and structure solving algorithms makes it possible to extract the crystal structure from the XRPD pattern. Recently, peers introduced a protocol to confirm the refined result using combination of XRPD and solid state NMR data. The NMR chemical shift values (1H, 13C, 15N) were also computed to validate the refined cocrystal structure.