Table 1.
Pharmacokinetic parameters (mean and range) generated by non-compartmental analysis for fentanyl following placement of two (LDF), four (MDF), and six (HDF) 100 mcg/h matrix patches in healthy adult horses (n = 6).
| LDF | MDF | HDF | |
|---|---|---|---|
| Cmax (ng/ml) | 1.39 (0.82−1.82) | 2.64 (1.21–4.42) | 4.11 (2.78−7.12)a |
| Tmax (h) | 12.7 (8.0–16.0) | 12.7 (8.0–16.0) | 12 (8.0–16.0) |
| AUCinf (h ng/ml) | 42.37 (27.59–55.56) | 77.24 (45.62–115.06)a | 120.34 (100.66–150.55)a,b |
| AUC % extrap | 0.435 (0.170–0.821) | 0.805 (0.088–2.27) | 0.448 (0.200–0.846) |
| HL λZ (h) | 7.94 (6.37–11.4) | 9.73 (6.50–15.9) | 9.18 (6.71–12.2) |
| λZ (1/h) | 0.091 (0.061–0.109) | 0.080 (0.044–0.107) | 0.079 (0.057–0.103) |
| Cl/F (ml/min/kg) | 15.57 (11.36–22.88) | 9,929.3 (5,794.0–14,608.8) | 16.01 (12.58–18.81) |
| Vd/F (L) | 5,558.9 (3,535.0–7,202.2) | 9,098.9 (3,260.4–16,768.9) | 6,583.3 (4,706.2–7,694.1) |
Cmax, maximum plasma drug concentration; Tmax, time of maximum plasma drug concentration; AUCinf, area under the curve extrapolated to infinity; AUC % extrap, percent of area under the curve extrapolated; HL λZ, terminal half-life; λZ, terminal slope of the plasma concentration time curve; Cl/F, systemic clearance per fraction absorbed for patch treatments, total systemic clearance for IV treatment; Vd/F, volume of distribution per fraction absorbed for patch treatments and volume of distribution at steady state for intravenous treatment.
Significantly greater than LDF (p < 0.008, for both).
Significantly greater than MDF (p = 0.002).