Research Journal of Pharmacy and Technology

Cinnamic acid cocrystals have been synthesized with nicotinamide coformers using the solvent evaporation method to produce white crystals. Characterization results with DSC show that cinnamic acid cocrystals have different endothermic peaks of 110°C, cinnamic acid (136°C), and individual nicotinamide (127°C). PXRD results where cinnamic acid cocrystals have different diffractogram patterns with individual cinnamic acid, namely diffractogram peaks at 6.7°, 13.4°, and 20.2°. The FTIR characterization results also indicate that cinnamic acid cocrystals exhibit distinct FTIR spectra. Specifically, there is an absence of twin peaks in the wave number range of 3400-3000 cm^-1 corresponding to the -NH group, and absorption peaks resembling fusion appear at wave numbers around 1600 cm^-1 and 1500 cm^-1, corresponding to -C=O and -C=C alkene groups. Additionally, SEM analysis reveals that while cinnamic acid has an irregular plate-like shape, the formed cocrystals exhibit a smooth surface morphology and an irregular block-like shape. Furthermore, the solubility test demonstrates that the solubility of cinnamic acid increases from 0.57 g/100 ml to 1.09 g/100 ml after cocrystallization, indicating a proportional enhancement in Dissolution Efficiency (DE) from 80.104% to 96.021%. The bond formation in the cocrystal is a hydrogen bond, as indicated by the isosurface map and the RDG Scatter Plot. This bond occurs between the carboxylic group of cinnamic acid and the amide group of nicotinamide in the C=O_CA…_NICH-N synthon, as well as between the hydroxide group of cinnamic acid and the carboxylic group of nicotinamide in the O-H_CA…_NICO=C synthon. The hydrogen bond is represented by a blue spike at sign(λ₂)ρ around -0.04 a.u.