The purpose of this study was to compare the bioavailability of equine firocoxib to canine chews in horses as well as evaluate therapeutic levels with clinical response. Horses (n=8) received a single loading dose of firocoxib (0.3 mg/kg) as an oral paste, chew, or intravenously in a randomized triple cross over study. Firocoxib was quantitated by high performance liquid chromatography (25-2,500 ng/ml). Data was subjected to non-compartmental analysis. An in vitro analysis was performed to determine appropriate handling of firocoxib during collection and storage. Samples from client horses (n=44) treated with firocoxib chews were evaluated for drug levels and clinical response. This study failed to find statistically significant differences in Cmax and absolute oral bioavailability at a power of greater than or equal to 90%. Firocoxib should be transported and stored in glass vials. Clinical patients appear to respond favorably to treatment with chews without adverse effects.

OBJECTIVETo describe in vitro elution characteristics of amikacin and vancomycin from calcium sulfate hemihydrate 98% (plaster of Paris, POP) beads and characterize eluent inhibition of Staphylococcus spp.STUDY DESIGNExperimental study.METHODSPOP beads were impregnated with amikacin or vancomycin alone or in combination and then incubated alone or in combination for 84 days at 37 degrees C in plastic tubes containing sterile phosphate-buffered saline (PBS). Beads containing no antimicrobial served as negative control. Beads were intermittently moved to a new tube containing drug-free PBS. Antimicrobial was measured in the eluent using a polarized fluorescent immunoassay. Eluent inhibition of Staphylococcus spp. was determined at each time point.RESULTSAntimicrobial release from beads was characterized by an initial rapid phase then a slower phase. Although antimicrobial release from beads occurred throughout the 84 days, most was in the first 24 hours, except for vancomycin alone. Duration of eluent inhibition of Staphylococcus spp. growth ranged from 0.5 (amikacin alone) to 56 days (vancomycin alone). Control eluent did not inhibit bacterial growth.CONCLUSIONSAmikacin elution from POP beads was rapid, inhibiting growth for <24 hours with or without vancomycin. Vancomycin elution was slower and inhibited growth for 56 days alone or for 5 days with amikacin.CLINICAL RELEVANCEVancomycin-impregnated beads appear to be reasonable as a therapeutic option whereas amikacin-impregnated POP beads and amikacin and vancomycin combinations may require further study before considering as a therapeutic option.