Formulation and evaluation of ocular drops containing solid dispersion of tobramycin

Tobramycin is a potent antimicrobial aminoglycoside that can be used to treat ocular infections. Its solubility and bioavailability are limited, so its solid dispersion was prepared using PVP-K30, HPMC and Beta cyclodextrin by solvent evaporation technique. This solid dispersion was formulated as an eye drop using sodium chloride, EDTA and benzalkonium chloride. Totally 9 formulations were prepared. The in-vitro dissolution profile of optimised formulation (F6) showed 85.1% drug release at the end of 2nd hour. The optimized formula was evaluated which showed no microbial growth, and drug content uniformity was 80.12% to 85%. The optimized formulation was evaluated for clarity, pH, isotonicity, microbial growth, stability and in vitro diffusion studies and all these showed acceptable results.