Subcutaneous meloxicam suspension pharmacokinetics in mice and dose considerations for postoperative analgesia

Chen, Patty H.; Boyd, Kelli L.; Fickle, Erin K.; Locuson, Charles W.

Meloxicam is a cyclooxygenase (COX) inhibitor with a higher selectivity for cyclooxygenase‐2 (COX‐2) than for cyclooxygenase‐1 (COX‐1). In the laboratory setting, this nonsteroidal anti‐inflammatory drug (NSAID) is commonly selected for analgesia in mice and administered every 24 h. This study characterizes the plasma concentration achieved from a dose of 1.6 mg/kg of meloxicam administered once every 24 h subcutaneously for 72 h in male and female C57BL/6 mice. These values were compared, over time, to reference COX‐2 inhibition constants for meloxicam. No significant differences in trough plasma concentrations were noted between genders. The plasma concentrations were below the COX‐2 IC (50) after 12 h. To maintain a plasma concentration at or above the COX‐2 whole blood IC (50,) the study results suggest an administration frequency of every 12 h when using a dose of 1.6 mg/kg in C57BL/6 mice.