Structural Analysis of Ciprofloxacin-Carbopol Polymeric Composites by X-Ray Diffraction and Fourier Transform Infra-Red Spectroscopy

Purpose: To evaluate physicochemical changes in ciprofloxacin following incorporation in Carbopol polymeric composites.
Methods: The ciprofloxacin and Carbopol were mixed in water in a drug:polymer ratio of 1:5 (w/w) and homogenized to produce uniform composites. X-ray powder diffraction analysis of the pure ciprofloxacin and the Carbopol polymeric composites of the drug were obtained using a powder diffractometer. Spectra for the materials were also generated by Fourier transform infrared (FTIR) spectroscope interfaced with an infrared (IR) microscope operated in reflectance mode.
Results: Based on the Hanawalt system, three prominent x-ray diffractogram (XRD) peaks of the pure ciprofloxacin and the drug in the polymeric composites exhibited d-spacing at similar 2θ values, but the relative intensity of these peaks was higher in the polymeric composites. FTIR analysis indicates that there were intermolecular hydrogen bonding and esterification between the drug and polymer in the polymeric composites.
Conclusion: The changes that occurred in ciprofloxacin indicate increase in stability, decrease in solubility and delayed release of the drug from polymeric composites which could facilitate the formulation of a sustained release form of the drug.

Keywords
Ciprofloxacin, X-ray diffraction, Fourier transform infrared, Carbopol, Polymeric composites