[The dynamics of melanin-affinitive and non-affinitive antibacterial agents in the iris-ciliary body of rabbit eyes--comparative studies in pigmented and albino rabbits].

The differences between the drug penetration levels in the iris-ciliary bodies of sparfloxacin (SPFX) and cefmenoxime (CMX), which respectively have high and low affinity to melanin, were examined using pigmented and albino rabbit eyes. Each drug was mixed with a homogenate of the iris-ciliary bodies of pigmented and albino rabbit eye, respectively. All CMX was distributed in a water soluble protein of the above homogenate of both pigmented and albino eyes, while all SPFX was detected from the water soluble protein of the tissue homogenate of the albino eye. However, in homogenate of the pigmented eyes, 60% of the drug was detected from water soluble protein and 20% of that was detected from water non-soluble protein. In the in vivo study, each drug was topically administered to pigmented and albino rabbit eyes. The SPFX concentration in the iris-ciliary body was significantly higher in the pigmented than in the albino eyes. The results indicated that the intraocular dynamics of the drug which has a high affinity to melanin showed significant differences between pigmented and albino rabbit eyes. This should be considered in studies of ocular pharmacology as an important factor which influences intraocular drug dynamics.