Investigation and characterization by TG/DTG-DTA and DSC of the fusion of Riboflavin, and its interaction with the antibiotic norfloxacin in the screening of cocrystal

Author(s)

Ferreira, Laura Teofilo ^[1] ; Alarcon, Rafael Turra ^[1] ; Perpetuo, Glauco Lini ^[2] ; Bannach, Gilbert ^[1]

Affiliation

^[1] UNESP Sao Paulo State Univ, Dept Chem, Sch Sci, Bauru, SP - Brazil

^[2] UNESP Sao Paulo State Univ, Engn Coll Bauru, Bauru, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY; v. 136, n. 2, p. 581-588, APR 2019.
• Web of Science Citations: 0

Abstract

This work synthesized and characterized the NOR-RIB 1:1 (mol-mol) cocrystal. During a study of the reagents, Riboflavin (RIB) melted at 304 degrees C, which is different from the temperature previously reported in the literature (280-290 degrees C); therefore, this compound was characterized individually. Subsequently, the cocrystal was synthesized with the active pharmaceutical ingredient (API) norfloxacin (NOR) with the RIB coformer, and the mechanochemical synthesis route was adopted. NOR, RIB, and the cocrystal were characterized by thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), DSC coupled to a microscope (photo-DSC), mid-infrared spectroscopy (MIR), and powder X-ray diffraction. The results of thermal analysis showed that the RIB starts decomposition process (260 degrees C) and then melts (304 degrees C). The MIR found that beginning at 295 degrees C, the RIB passes into the form of a decomposition intermediate; therefore, the melting point observed in the DSC curve is related to this decomposition material. The cocrystal presented thermal stability (200 degrees C) lower than the API (235 degrees C) and the coformer (260 degrees C). The DSC curve did not contain a melting peak. The bands at 1726 cm(-1) (C=O of the carboxylic acid) for the NOR, and the band at 3326 cm(-1) (stretch O-H), among others, were not visible for the cocrystal in the MIR spectrum, indicating interactions in these regions. The X-ray diffractograms showed a new diffraction pattern, which proved the obtainment of a new phase and cocrystal formation. (AU)

• FAPESP's process: 13/09022-7 - Thermoanalytical studies, synthesis and characterization of the solid co-crystals of antibiotics (fluoroquinolones) with some co-formers
• Grantee: Massao Ionashiro
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/03460-6 - Structural modification of triglycerides aiming new monomers and polymers, using different synthetic routes: microwave irradiation and photopolymerization
• Grantee: Rafael Turra Alarcon
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/08820-8 - Synthesis and characterization of biopolymers from vegetable oils and glycerol following the principles of green chemistry
• Grantee: Gilbert Bannach
• Support Opportunities: Regular Research Grants