Pharmacokinetics of secobarbital in rabbit.

The pharmacokinetic study of secobarbital in the rabbit utilizing gas chromatography (GC) indicated a correlation between blood levels and brain tissue levels; and that the distribution of the drug appears to be more complex than a first order process is suggested by the compartmental simulation midel. The liver and kidney which eliminate the drug into bile and urine, respectively, tend to follow first order elimination kinetics more closely than those which act as depots for drug storage such as muscle and fat. The two dose levels of secobarbital indicate the same relationship with blood and tissues, therefore an increase or decrease in the dosage has no effect on the pharmacokinetics of secobarbital. The termination of action of secobarbital is due to the combination of rapid uptake by liver and its disposition there and a slower uptake by muscle. Computer simulation of secobarbital distribution has strongly suggested the elimination of this drug in bile and that the rebound rise in liver amy be due to enterohepatic circulation.