Synthesis, Characterization and Antimicrobial Evaluation of Lipid Based Norfloxacin Prodrug

Background Fluoroquinolones, the synthetic antibacterial agents are being successfully utilized against bacterial infections, since the time immemorial. Despite of enormous useful features, these drugs are associated with some limitations also. Large number of efforts has been made by various scientists to improve pharmacokinetic properties of these drugs and hence, to overcome the limitations associated with them. Objectives The aim of this paper is to introduce a novel scheme for synthesis of prodrug with improved pharmacokinetic properties i.e., lipophilicity and consequently, modified bioavailability of norfloxacin. Methods Fatty acid hydrazide of selected fatty acid was synthesized followed by preparation of 5-formyl salicylamide. N-Mannich base of norfloxacin was synthesized by reacting norfloxacin with 5-formyl salicylamide. The prodrug was obtained by covalently coupling this N-Mannich base of norfloxacin with fatty acid hydrazide. The synthesized lipid based prodrug was evaluated for partition coefficient by shake flask method and screened for antimicrobial activity against selected strains. Drug content determination and in vitro dissolution studies utilizing HPLC were also carried out. Results The synthesized prodrug was found to exhibit improved partition coefficient (1.15) when compared with parent drug, norfloxacin (0.46). The results of antimicrobial evaluation indicate promising antibacterial and antifungal activity. Conclusion The synthesized prodrug proved to be a good antimicrobial substance due to improved lipophilicity and would be expected to be used as a suitable candidate for exploration of possible utilities in treatment of bacterial infections in forthcoming time.