In-house reference materials: 5-hydroxyflunixin and meloxicam in cow milk-preparation and evaluation.

Reference materials are helpful to evaluate the performance of laboratories as well as being useful for the quality control of analytical procedures. Certified reference materials and other reference materials containing non-steroidal anti-inflammatory drugs in milk are however, not available. Therefore, production and evaluation of in-house reference materials with incurred residues of 5-hydroxyflunixin (5OHFLU) and meloxicam (MEL) in cow milk has been performed. The milk was collected 12h after dosing from cows which received meloxicam (0.5 mgkg(-1) b.w., i.v., single dose) or flunixin meglumine (2.2 mgkg(-1) b.w., i.v. during three days). The concentrations of analytes were checked in the milk samples. The milk was diluted with milk free from NSAIDs residues, homogenised, put into sterile 20 mL vials, frozen and lyophilised. The vials were weighed before and after lyophilisation, in order to calculate the amount of water necessary for reconstitution, and were stored at a temperature of -20+/-2 degrees C. For the homogeneity study, 10 random samples were analysed in duplicate and the results were interpreted using Cochran's test, Horwitz standard deviation and the test for a sufficient homogeneity. The assigned values, calculated from the results of the homogeneity test were 54.3 microgkg(-1) for 5OHFLU and 46.4 microgkg(-1) for MEL. The samples were tested for their stability every 14 days for 2 months and after 9 months. It has been confirmed that an appropriate homogeneity and stability of the produced in-house reference material has been obtained.

Drug distribution and stability in extemporaneous preparations of meloxicam and carprofen after dilution and suspension at two storage temperatures.

OBJECTIVE: To determine dispersion uniformity and stability of meloxicam and carprofen in extemporaneous preparations stored for 28 days. DESIGN: Prospective study. SAMPLE POPULATION: Meloxicam and carprofen (commercial formulations) were compounded (day 0) with deionized water (DW), 1% methylcellulose gel (MCG), MCG and simple syrup (SS; 1:1 mixture), or a suspending and flavoring vehicle combination (SFVC; 1:1 mixture) to nominal drug concentrations of 0.25, 0.5, or 1.0 mg/mL and 1.25, 2.5, or 5.0 mg/mL, respectively. PROCEDURES: Preparations were stored at approximately 4 degrees C (39.2 degrees F) or 22 degrees C (71.6 degrees F). For each preparation, drug concentrations were determined and drug stability was evaluated at intervals during storage; on days 0 and 28, pH values were measured and bacterial cultures were initiated. RESULTS: In meloxicam-DW, meloxicam-MCG (0.25 mg/mL), and meloxicam-MCG (0.5 mg/mL) preparations, drug distribution was uniform (coefficient of variation < 10%); > 90% of the original drug concentration was maintained for 28 days. Despite uniform drug distribution of the carprofen-SFVC preparations, most retained > or = 90% of the original drug concentration for only 21 days. Use of the MCG-SS combination resulted in foamy preparations of unacceptable variability. After 28 days, pH decreased slightly in meloxicam-DW and meloxicam-MCG preparations (0.17 +/- 0.04 and 0.21 +/- 0.04, respectively). Carprofen-SFVC (2.5 mg/mL) and carprofen-MCG-SS (5.0 mg/mL) preparations stored at 22 degrees C for 28 days yielded bacterial growth. CONCLUSIONS AND CLINICAL RELEVANCE: DW, MCG, and the SFVC can be used successfully for extemporaneous preparation of meloxicam and carprofen for administration to small exotic animals. Refrigeration is recommended for preparations of meloxicam-DW and carprofen-SFVC.

Kinetic gait analysis assessment of meloxicam efficacy in a sodium urate-induced synovitis model in dogs.

OBJECTIVE: To examine the ability of meloxicam, a cyclooxygenase inhibitor, to mediate the effects of sodium urate-induced acute stifle synovitis in dogs. ANIMALS: 12 clinically normal adult hound-type dogs. PROCEDURE: A blinded, randomized, controlled single crossover design study was performed to determine the efficacy of meloxicam, using 2 dosage groups. In 2 experimental phases, dogs, according to group, received meloxicam (0.1 or 0.5 mg/kg of body weight) or matched volume of meloxicam vehicle, with a washout period of 21 to 28 days between phases. Blood samples for hematologic and biochemical analysis, as well as synovial fluid or cytologic analysis, were collected immediately before and approximately 24 hours after articular challenge of dogs under propofol anesthesia. Ground reaction forces (GRF) and subjective clinical scores were determined before and at 4, 8, 12, and 24 hours after articular challenge. Vertical force data included peak force, impulse, limb loading, and unloading rates. Craniocaudal data were divided into braking and propulsion phases and consisted of peak force and associated impulses. RESULTS: Except for propulsion impulse at 24 hours, all GRF variables were significantly greater at all post-synovitis induction times in the group receiving the high meloxicam dose. Significant differences in all GRF variables were seen at various times between the low-dose meloxicam group and the corresponding control group, and between the low- and high-dose meloxicam groups. Similar significance was seen in the subjective clinical evaluations. Strong correlations existed between the subjective and objective data. CONCLUSIONS: Meloxicam was effective in attenuating the effects of sodium urate-induced acute synovitis in dogs. Kinetic gait data provided an objective measurement of lameness in an experimentally induced arthritis model and quantified lameness improvements in response to medication with a nonsteroidal anti-inflammatory drug.