Formulation and evaluation of sparfloxacin emulsomes-loaded thermosensitive in situ gel for ophthalmic delivery

The aim of the present study was to develop thermosensitive emulsomal in situ gel for ocular delivery of sparfloxacin, an antibacterial drug. The study was conducted in two steps. In the first step, sparfloxacin emulsomes were prepared by thin film hydration technique and characterized. Compritol 888 ATO (CA) was used as lipid core and Phospholipon 90G (PC) as stabilizer. The optimized emulsomal formulation (E3) showed mean particle size of 217 ± 3.78 nm, with 72.83 ± 2.56 % drug entrapment efficiency, and showed a slow and consistent release of the drug over period of 24 h in simulated tear fluid (STF) pH 7.4. In the second step, the drug-loaded emulsomal suspension was dispersed in Pluronic (PF 127 and PF 68) solution yielding the emulsomal in situ gel. The optimized gel formulation GF1 gelled at around 35 °C. Drug content was found to be 92.42 ± 2.08 %. The viscosity of the formulation at 25 ± 1 and 37 ± 1 °C was 107.46 ± 6.74 and 1669 ± 13.89 cps, respectively. The in vitro drug release revealed a sustained profile over a period of 12 h. The formulation was non-irritant and showed promising in vitro and in vivo antimicrobial activity. Stability studies indicated that 4 ± 1 °C is appropriate storage condition for the formulation. The findings suggested that the novel emulsomal in situ gelling system could be a viable alternative to conventional eye drops.