Physical-chemical characterization of N-acylhydrazone derivative chitosan films using spectroscopic and thermoanalytical techniques

The N-acylhydrazone subunit is present in several bioactive molecules and drug prototype candidates, yet it remains under-explored. The association of an N-acylhydrazone derivative (JR19) with chitosan (CHI), a biopolymer with attractive pharmaceutical characteristics, may represent an innovative proposal for the treatment of topical inflammation. The aim of this work was to perform a physical-chemical characterization of chitosan films containing JR19 using differential scanning calorimetry (DSC), thermogravimetry and its derivative (TG/DTG), Fourier-transform infrared spectroscopy, and X-ray diffraction techniques. The films were developed using the sol-gel process and, according to the DSC curves, demonstrated the compatibility of the physical mixture (CHI+JR19) and the absence of chemical incompatibility of the polymer films incorporated with JR19. The TG/DTG presented similar characteristics of loss of mass between the samples, the prevailing characteristics of CHI. The infrared spectra of the physical mixture and the film with the molecule exhibited bands characteristic of the functional groups of JR19 in the same absorption region. The reflections observed in the diffractograms indicated a decrease in the crystallinity of the films when compared to the physical mixture and omission of some reflections of JR19 in the films. Therefore, the techniques used enabled the characterization of the formulation of CHI and JR19, proving very promising for the development of these films/dressings as an innovative proposal for pharmaceutical treatment, considering their low cost, biocompatibility, and the biological properties of JR19 against different diseases (parasitic, viral, bacterial, fungal, analgesic, anti-inflammatory, and antitumor).