We have evaluated the percutaneous penetration of
felbinac following application of topical patches using a microdialysis technique, and have examined correlations with pharmacological effects. A linear microdialysis probe with a 20-mm dialysis fibre was inserted into the skin of anaesthetized rats. Probe perfusion was started at 2.0 microL min(-1) with physiological saline and after a 60-min baseline sampling of
dialysate, 0.1 mL
croton oil was applied to the skin surface at a concentration of 8%, v/v. A
felbinac patch was then applied to the same point 60 min thereafter and
dialysate was sampled at 60-min intervals up to 300 min after patch application, for determination of concentrations of
felbinac and
prostaglandin (PG) E2.
Analgesic effects of
felbinac patches in an iodoacetateinduced
osteoarthritis model and an incisional
pain model were evaluated using the weight bearing method. After application of patches,
felbinac penetration into the skin was rapid, maximum concentrations in the
dialysates with 0.07, 0.5 and 3.5% w/w
felbinac patches being 0.046+/-0.02, 0.104+/-0.06 and 0.244+/-0.2 microg mL(-1), respectively.
Dermal administration of
croton oil caused an increment in
PGE2 levels, which was significantly decreased by 0.5 and 3.5%
felbinac patches 2-5 h after application. In pharmacological studies, 3.5%
felbinac patches suppressed
pain-associated behaviour induced by iodoacetate injection and plantar incision. These results suggested that the
transdermal patch containing 3.5%
felbinac may become a useful formulation.