MICROENCAPSULATION OF KETOROLAC TROMETHAMINE BY MEANS OF A COACERVATION PHASE-SEPARATION TECHNIQUE INDUCED BY THE ADDITION OF NONSOLVENT

Ketorolac tromethamine (KT) is a non-steroidal drug with potent analge sic and anti-inflammatory activity and is absorbed rapidly (T-max (1.0 h) with an efficiency >87% following oral and intramuscular administra tion. The plasma half-life of ketorolac ranges from 1.1 to 6.0 h. Its oral bioavailability is estimated to be 80%. Ketorolac has been found 36 times more potent than phenylbutazone, approximately twice as poten t as indomethacin, and three times more potent than naproxen in suppre ssing carrageenan-induced paw oedema in rat. In this study, microcapsu les of KT were prepared by means of coaceruation-phase separation tech nique induced by the addition of non-solvent, and release rates from m icrocapsules were studied. Eudragit S100 was used as the coating mater ial. Coacervation was achieved by the addition of cyclohexane at 2 ml/ min at 25 degrees C and 1:4 solvent:non-solvent ratio was used. The mi crocapsules were washed with cyclohexane to harden the wall and dried at room temperature. Microcapsules with core:wall ratio of 1:1 and 1:2 were prepared and the particles obtained by sieving with an average d iameter of 177-500 mu m were used. The yield was calculated and the re lease properties of KT were investigated by USP XXII paddle method and using UV spectrophotometry at 318 and 323 nm.