It was found that the formation pathway and kinetics of the grinding process depend on the form of the starting material and reaction conditions. The mechanism of the phase transformation between the crystalline forms was evaluated under mechanochemical conditions. Real-time in situ Raman spectroscopy was used to investigate the mechanochemical formation pathways of the different solid polymorphs of ciprofloxacin salicylate. The salicylate salts were investigated by different analytical techniques ranging from powder and single crystal X-ray diffractometry, differential scanning calorimetry, thermogravimetric analysis, variable temperature powder X-ray diffraction, dynamic vapor sorption analysis, dissolution, and solubility investigations.
The crystallization of ciprofloxacinan antibacterial fluoroquinolone compoundwith salicylic acid resulted in the isolation of five distinct solid forms of the drug, namely, an anhydrous salt, two polymorphic forms of the salt monohydrate, methanol and acetonitrile solvates, and the salt-cocrystal hydrate. Enhanced solubility was found in the salts of amoxapine for pharmaceutical application in drug formulation. Salts of amoxapine with different acids were successfully developed, and their crystal structure was determined. Solubility of salts was determined in water by the shake-flask method at 37☌ using UV−vis spectroscopy.
Salts were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and powder X-ray diffraction. Crystal structures of API salts were determined by single-crystal X-ray diffraction. Single crystals of cocrystals were grown by the solvent evaporation method in water, ethanol, and methanol. Amoxapine has very low solubility in water, so it was cocrystallized with natural acids in a 1:1 ratio in appropriate solvents by the solvent-drop grinding method. Amoxapine is a benzox-azepine derivative and exhibits antidepressant properties. The objective of pharmaceutical cocrystalliza-tion is to create crystalline analogues that have vastly different properties, such as solubility, melting point, stability, and bioavailability from that observed in the pure active pharmaceutical ingredients (APIs). Two guided inquiry research type assignments are herein discussed that expose students to crystallography and enhance literature review/analysis skills that allows them to become better undergraduate researchers. Thus, the aim of this article is to touch upon the attempts to introduce the topic of crystallography to undergraduates of the inorganic chemistry laboratory at Georgia College and State University (GCSU). While accessibility to high-tech instrumentation is indeed an obstacle, there are educational sources that are quite accessible for undergraduate students, merely requiring a working computer to make use of them. State of the art X-ray diffraction instruments typically reach the ~$500,000 range and are rarely available to primarily undergraduate institutions.
Several attempts have been made to introduce crystallography topics at the undergraduate level, but the one present obstacle is the availability of instrumentation for undergraduates to run experiments in. Chemical crystallography is considered one of the essential characterization techniques of inorganic chemistry since it is a critical tool in the structural determination of molecules small and large.
0 kommentar(er)
