English Abstract
Abstract:
To overcome the issue of multidrug resistant (MDR) microbes, the exploration of ways
to improve the antimicrobial efficiency of existing antibiotics is one of the promising approaches.
In search of synthons with higher efficiency, in current investigations, cocrystal and amorphous
salt of levofloxacin hemihydrate (LEV) were developed with phthalimide (PTH) and caffeic acid
(CFA). New materials were characterized with the help of FT-IR, Raman spectroscopy, powder X-ray
diffraction (PXRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).
Shifting, attenuation, appearance/disappearance and broadening of bands were observed in the FT-IR
and Raman spectra of the materials as evidence of the required product. The PXRD diffraction pattern
observed for LEV-PTH indicated cocrystal while halo diffractogram of LEV-CFA revealed amorphous
nature. DSC/TG analysis confirmed the hydrated nature of the cocrystal/salt. The dissolution rate
and antimicrobial activity against selected strains, K. pneumonia, E. coli and S. typhi of parent drug
and the new material were compared. The zone of inhibition (ZI) observed for 5 µg LEV-PTH was
30.4 + 0.36 (K. pneumonia), 26.33 + 0.35 (E. coli) and 30.03 + 0.25 mm (S. typhi) while LEV-CFA salt
(5 µg) against the same strains inhibited 33.96 ± 0.25, 31.66 ± 0.35 and 27.93 ± 0.40 mm, respectively.
These novel formulations enhance the dissolution rate as well as antibacterial efficiency and are
expected to be potent against MDR bacterial strains.