Table 2.
Observed and fitted pharmacodynamic parameters describing improvement of locomotion after a single administration of a nominal dose of 0.3 mg kg−1 meloxicam in five cats
| End point | Tmin (h) | Rmin (no unit or %) | A (h−2 or % h−2) | Alpha (no unit) | β (h−1) | Kout (h−1) | Imax (%) | IC50 (ng ml−1) | n (no unit) |
|---|---|---|---|---|---|---|---|---|---|
| Lameness score (no unit) | 5.6±3.7 | 3.0±0.0 | 494±396 | 2.66±1.13 | 1.80±0.65 | 24.7±16.1 | 75.4±18.2 | 911±189 | 8.2±2.4 |
| Overall locomotion variable (%) | 8.6±3.8 | 206.2±42.7 | 46027±49527 | 1.30±0.61 | 0.91±0.16 | 76.7±88.9 | 64.1±20.9 | 841±187 | 10.0±0.0 |
Values are mean±s.d. Tmin (h) and Rmin (same unit as endpoint, i.e., no unit (lameness score) or % (overall locomotion variable)) are observed values for the time of occurrence of the peak response and the maximum meloxicam response expressed as a decrease in the endpoint value, respectively. Locomotion times were transformed to percentages (using an equivalent of equation (1)) and added to obtain an overall locomotion variable. Data were fitted with an integrated PK/PD model, taking into account the spontaneous evolution of the inflammation (see equation (8)). The rate of change of the response over time as well as the meaning of the parameters of the gamma function (A, α and β) and Kout, IC50, Imax and n are given by equation (8).