ESTUDO DE COMPOSTOS DE AZITROMICINA VIA DIFRAÇÃO DE RAIOS X E ESPECTROSCOPIA RAMAN

Abstract

Azithromycin (AZM) is a 15-membered semisynthetic macrolide, which is derived from erythromycin A, stands out for having a broad spectrum of action against Gram-positive and Gram-negative bacteria, becoming the most widely used antibiotic worldwide, but the antibiotics have become resistant to microorganisms, so a possible way to circumvent such resistance mechanisms is the coordination of metal ions to antibiotics. In this context, this work aims at the synthesis and growth of azithromycin crystals, as well as the study of their structural, vibrational and thermal properties. All materials were obtained by the ELS method. The obtaining of the AZM-MH-EtOH crystal was confirmed by XRD technique along with refinement by the Rietvield method verifying that the crystal presents a monoclinic system with space group P21, containing 4 molecules per unit cell. The AZM-Cu (II) metal complex showed violet coloration and diffraction pattern different from those reported in the literature, indicating the formation of a new phase. AZM-TRIS-Cu(II) showed absence of X-ray diffraction peaks in the diffractogram, confirming the amorphization of the material. According to the group theory for the AZM-MH-EtOH crystal the modes are active in both infrared and Raman, therefore, the characterization by Raman Spectroscopy made it possible to analyze the possible vibrational bands of this solvate in three regions of the spectrum, such as: twists of the CCCH and CCOH groups, combinations of twists, and the structures of the lactone, cladinose and desonamine rings, stretching modes of the C44C48 and C9C8 units, angular strains of the CCC bond, among other assignments. It was possible to identify by FT-IR, assigned vibration bands of the hydroxyl (OH) and a set of stretching assigned to the CH3, CH2 and CH groups. Stretching of the carbonyl group was also observed, which may participate in the formation of hydrogen bonds. The thermal analyses performed by TG-DTG indicated that the thermal stability of this solvent was up to 487 K. DTA and DSC curves indicated that the sample undergoes dehydration and subsequently amorphization of the material occurs around 386-390 K. This amorphization was confirmed by XRD as a function of temperature. Finally, the results obtained in this work can contribute to various areas of knowledge as well as to the pharmaceutical industry and drug handling because it has unprecedented results for the antibiotic azithromycin.