A Comparison of the Properties of Some Chloramphenicol and Neomycin Eye Ointments, Commercially Available in the U.K

Abstract

The rheology, particle size distribution and drug release, measured by dissolution and agar diffusion techniques, of five B.P. Chloramphenicol Eye Ointments and three B.P. Neomycin Eye Ointments have been examined. All ointments showed structural breakdown during continuous shear rheology. Three chloramphenicol ointments displayed spur values whilst one neomycin ointment displayed a bulge on the up-curve of the rheogram. Mass median particle sizes ranged from 6.0 to 13.0 and 5.4 to 9.6 μm for the chloramphenicol and neomycin ointments respectively. Drug release similarly varied. By dissolution techniques the quantity of chloramphenicol that dissolved in 60 minutes ranged from 22 to 41 μg whilst agar diffusion studies produced drug releases which varied from 2.4 to 4.7 and 0.8 to 2.3 μg for the chloramphenicol and neomycin results respectively.