TABLE 1.

Pharmacokinetic characteristics of (−)-naloxone and (+)-naloxone in the blood after a subcutaneous injection of 0.1 mg/kg^a

Parameter	(−)-Naloxone	(+)-Naloxone
AUC (µM·min)	1.05	0.94
Cmax (µM)	0.04	0.03
Tmax (min)	10.89	9.33
Ka (min−1)	0.09	0.19
Ke (min−1)	0.09	0.05
t1/2 (min)	7.67	12.82

^aAll parameters are calculated by the Kinetica software based on a one-compartment extravascular model fitted to the mean blood concentrations of (−)-naloxone and (+)-naloxone obtained in vivo (n = 4–6 in each group).

AUC, area under the curve; C_max, maximum concentration; K_a, absorption constant; K_e, elimination constant; t_1/2, half-life during elimination; T_max, estimated time to reach C_max.