ABSORPTION OF SODIUM DICLOFENAC AFTER OCULAR ADMINISTRATION IN RABBIT

Sodium diclofenac (DCF, CAS 1507-79-6) is a non-steroidal anti-inflamm atory drug whose activity is mainly due to an inhibitory effect on the synthesis of the prostaglandins. At present, a tendency towards its t opical use in the treatment of the inflammatory state of the anterior segment of the eye as an alternative to the steroid drugs is observed. The pharmacokinetics of DCF was studied in rabbits by assessing the o cular and systemic absorption of DCF after administering DCF ye drops. The chromatographic methods available were not sensitive enough to qu antify the extremely low drug concentrations which appeared in the bio logical fluids after ocular treatment. For this reason, the concentrat ions of DCF in plasma and aqueous humor were evaluated by a coupled li quid chromatography/gas chromatography (LC/GC) method. DCF was absorbe d well through the cornea with the aqueous humor concentration peak be ing 757.8 ng/ml at 120 min. This good ocular absorption of DCF was con firmed by the concentrations observed in plasma. The presence of trama zoline (TMZ, CAS 74195-73-6) in the eye drops increases the levels of DCF in aqueous humor.