Pharmacokinetics of meloxicam following intravenous administration at different doses in sheep

The aim of this study is to determine the pharmacokinetic change after intravenous administration of meloxicam at doses of 0.5, 1 and 2 mg/kg to sheep. The study was carried out on six Akkaraman sheep. Meloxicam was administered intravenously to each sheep at 0.5, 1, and 2 mg/kg doses in a longitudinal pharmacokinetic design with a 15-day washout period. Plasma concentrations of meloxicam were determined using the high performance liquid chromatography-ultraviolet, and pharmacokinetic parameters were evaluated by non-compartmental analysis. Meloxicam was detected up to 48 h in the 0.5 mg/kg dose and up to 96 h in the 1 and 2 mg/kg doses. As the dose increased from 0.5 to 2 mg/kg, terminal elimination half-life, and dose normalized area under the concentration versus time curve increased and total clearance decreased. Compared to the 1 mg/kg dose, it was determined that Vdss decreased and C0.083h increased in the 2 mg/kg dose. Meloxicam provided the therapeutic concentration of >0.39 μg/mL reported in other species for 12, 48 and 96 h at 0.5, 1 and 2 mg/kg doses, respectively. These results show that meloxicam exhibits non-linear pharmacokinetics and will achieve unpredictable plasma concentrations when administered IV for a rapid effect at dose of ≥1 mg/kg in sheep.

Effects of Apixaban, Rivaroxaban, Dabigatran and Enoxaparin on Histopathology and Laboratory Parameters in Achilles Tendon Injury: An in vivo Study

Objectives

To compare the effects of apixaban, rivaroxaban, dabigatran and enoxaparin on histopathology and blood parameters in rats with Achilles tendon injury.

Materials and Methods

Thirty adult, male Wistar albino rats weighting 220-240 g were randomly divided into five (one control and four treatment) groups and placed in a controlled environment. The Achilles tendon was incised and re-sutured in each rat, after which each group was provided the following treatment for 28 days: a) 2 ml saline to the control group, b) apixaban in 1 ml of saline (10 mg/kg/day) +1 ml of saline, c) rivaroxaban in 1 ml of saline (2 mg/kg/day) +1 ml saline, d) dabigatran in 1 ml of saline (30 mg/kg/day) +1 ml of saline, e) enoxaparin (80 μg/kg/day) + 2 ml of saline.

Results

Hemogram, biochemical and coagulation parameters differed significantly between the control and treatment groups (P < 0.05). Compared with the control group, in the apixaban group, type I and type III collagen immunoreactivity were severe and moderate, respectively. In the rivaroxaban and dabigatran groups, both type I and type III collagen immunoreactivity were medium and severe, respectively. In the enoxaparin group, type I and type III collagen immunoreactivity were mild and severe, respectively.

Conclusion

The higher concentration of type I collagen in the apixaban and dabigatran indicates faster tendon healing in these groups, and the higher concentration of the type III collagen in the enoxaparin group indicates slower healing in this group.