Ciprofloxacin (CIP), a widely used antibiotic, is a poor biopharmaceutical resulting in low bioavailability. We optimized a CIP polymer-lipid hybrid nanoparticle (CIP-PLN) delivery system to enhance its biopharmaceutical attributes and the overall therapeutic performance. CIP-PLN formulations were prepared by a direct emulsification-solvent-evaporation method. Varying the type and ratio of lipid was tried to optimize a CIP-PLN formulation. All the prepared formulations were evaluated for their particle size, polydispersity index, zeta potential, physical stability, and drug entrapment efficiency. The drug in vitro release profile was also studied. Antibacterial activities were tested by the agar diffusion method for all CIP-PLN formulations against an Escherichia coli clinical bacterial isolate (EC04). CIP-PLN formulations showed average sizes in the range of 133.9 ± 1.7 nm to 217.1 ± 0.8 nm, exhibiting high size uniformity as indicated by polydispersity indices lower than 0.25. The entrapment efficiency was close to 80% for all formulations. The differential scanning calorimetry (DSC) thermograms indicated the existence of CIP in the amorphous state in all PLN formulations. Fourier transform infrared spectra indicated deep incorporation of molecular CIP within the polymer matrix. The release profile of CIP from PLN formulas showed a uniform prolonged drug profile, extended for a week from most formulations with a zero-order kinetics. The antibacterial activity of CIP-PLN formulations showed significantly higher antibacterial activity only with F4 containing lecithin as the lipid component. In conclusion, we successfully optimized a CIP-PLN formulation with a low nanoparticle size in a close range, high percentage of entrapment efficiency and drug loading, uniform prolonged release rate, and higher antibacterial activity against the EC04 clinical isolate.
Keywords: DSC; Dynasan; Escherichia coli; agar diffusion; emulsification–solvent–evaporation.