PARTICLE SIZE ANALYSIS FOR OFLOXACIN, PREDNISOLONE ACETATE, AND AN OPHTHALMIC SUSPENSION CONTAINING THE OFLOXACIN/STEROID DRUG COMBINATION

Image analysis (LA), Photon Correlation Spectroscopy (PCS), and Single Particle Optical Sizing (SPOS) have been applied to the analysis of particle size for ofloxacin, prednisolone acetate and an ofloxacin/prednisolone acetate ophthalmic suspension. LA shows that ofloxacin particles suspended in mineral oil are on the order of 10 µor less. LA of prednisolone acetate in H 2 O shows that the steroid particles are agglomerated and range in size from 20 to 50 µ. SPOS is used to verify LA results for prednisolone acetate. LA of the ofloxacin/steroid balled milled suspension yields a particle size of ∼ 1 µ with a few particles on the order of 5 µ, PCS analysis of three batches of ball-milled ofloxacin/steroid suspension shows that increased ball-milling time increases the reproducibility of the mean diameter value as determined by PCS. It is also observed by PCS that the mean diameter of the steroid achieves a constant value with ball-milling from 11 to 14 days (1386.4 to 1383.4 nm). Extended ball-milling past the 14 day time point (18 days) appears to reduce sample inhomogeneity, thereby eliminating larger particulates with a subsequent reduction in the mean diameter to 1097.4 nm, Results for PCS analysis of the ball-milled ofloxacin/steroid suspension are verified by SPOS.