Formulation and comparative evaluation of HPMC and water soluble chitosan-based sparfloxacin nanosuspension for ophthalmic delivery

Ophthalmic nanosuspensions (ONS) have shown a potential for ophthalmic delivery over the conventional ocular formulations. The objective of the study was to assess the effect of surfactants and polymers on particle size and drug release. Sparfloxacin ONS were prepared by optimizing the concentration of HPMC E5 and water soluble chitosan by using solvent diffusion method followed by probe sonication. The Poloxamer 407 and Kolliphor P188 were used as a surfactant. The produced nanosuspensions were characterized for particle size, shape, zeta potential and drug release. The average particle size of the nanosuspension was 300 to 500 nm. The in vitro drug release study showed that the optimized nanosuspension of water soluble chitosan sustained drug release up to 9 h compared to 6 h for the hydroxypropylmethylcellulose (HPMC) nanosuspension. Further, the sparfloxacin ONS formulation showed excellent ocular tolerance and biocompatibility as determined by hen's egg test chorioallantoic membrane (HET CAM) and resazurin assay on Vero cell lines. Moreover, optimized formulation was found to be stable, isotonic, nontoxic with higher in vitro and in vivo antimicrobial potential.