Cocrystallization out of the blue: dl-mandelic acid/ethyl-dl-mandelate cocrystal

Weak Interactions in Cocrystals of Isoniazid with Glycolic and Mandelic Acids

This work deals with the preparation of pyridine-3-carbohydrazide (isoniazid, inh) cocrystals with two α-hydroxycarboxylic acids. The interaction of glycolic acid (H2ga) or d,l-mandelic acid (H2ma) resulted in the formation of cocrystals or salts of composition (inh)·(H2ga) (1) and [Hinh]+[Hma]–·(H2ma) (2) when reacted with isoniazid. An N′-(propan-2-ylidene)isonicotinic hydrazide hemihydrate, (pinh)·1/2(H2O) (3), was also prepared by condensation of isoniazid with acetone in the presence of glycolic acid. These prepared compounds were well characterized by elemental analysis, and spectroscopic methods, and their three-dimensional molecular structure was determined by single crystal X-ray crystallography. Hydrogen bonds involving the carboxylic acid occur consistently with the pyridine ring N atom of the isoniazid and its derivatives. The remaining hydrogen-bonding sites on the isoniazid backbone vary based on the steric influences of the derivative group. These are contrasted in each of the molecular systems. Finally, Hirshfeld surface analysis and Density-functional theory (DFT) calculations (including NCIplot and QTAIM analyses) have been performed to further characterize and rationalize the non-covalent interactions.

Synthesis and characterization of meloxicam eutectics with mandelic acid and saccharin for enhanced solubility

Meloxicam (MLX) is a non-steroidal anti-inflammatory which is practically insoluble in water, requiring high concentrations to reach therapeutic levels and causing frequently gastrointestinal effects. In this way, the aim of this study was to synthesize two eutectic mixtures of MLX with mandelic acid (MND) and saccharin (SAC) by liquid-assisted grinding resulting in a multicomponent material with enhanced solubility. Mixtures were studied in different stoichiometric and eutectic point was found for each eutectic by Binary phase diagram and Tamman's triangle, with 0.33 molar fraction of MLX for SAC and MND. Eutectics were characterized by thermoanalytical techniques (TG-DSC, EGA, DSC, and DSC microscopy), infrared spectroscopy, and X-ray powder diffraction. Thermal behavior was studied and videos of the materials being heated were available. A polymorphic transition was discovered and studied for MLX-MND eutectic. Each new system was evaluated by solubility, dissolution, and hygroscopicity tests. Eutectics showed an increase in solubility of 1.7× (MLX-MND1), 3.1× (MLX-MND2), and 1.3× (MLX-SAC) with slower dissolution profile when compared with MLX. All new solid forms showed high hygroscopicity at 98% relative humidity with 27.9 and 58.9% increase in mass at day four for MLX-SAC and MLX-MND, deliquescence occurs at day 6. The experiments and analysis in this study help to understand the behavior of eutectics and evaluate them as an approach to modify properties in drugs.