Intravenous injection single, kinetics

Table 7.1 Disposition kinetics of enrofloxacin and formation of ciprofloxcin in newborn and one-week-old Finnish Ayrshire calves. A single dose (2.5 mg/kg) of enrofloxacin was administered by intravenous injection to the calves (n = 4 in each age group). Results are expressed as mean + SEM and (range).

In healthy human subjects, a peak mean scrum concentration of 1607 p.g/liter was found 15 min after single bolus intravenous injections of 20 mg (Hilleslad etal.. 1974). A two-compartment open model has been used to describe elimination kinetics of diazepam in humans after single intravenous injections were reported (Andreasen etal., 1976 Klotz etal., 1975, 1976). A two-compartment open model has also been used to describe elimination kinetics of diazepam in experimental animals however, there were major interspccics differences in parameters such as r / and (Klotz etal., 1976), which indicated caution in the interpretation of animal studies. In human volunteers, the plasma protein binding of diazepam was greater than 95% (Klotz etal., 1976). The f /j of diazepam appears... 

Having demonstrated that the ovary has a specific capacity to concentrate HCG, the fate and some kinetics of HCG in infantile mice following intravenous injections were studied. Fig. 1 demonstrates the disappearance of labelled HCG from the circulation following a single intravenous injection. It can be noticed that the concentration fell to approximately 50% within the first 30 minutes and dropped to about 15% of injected material within the following hour thereafter the concentration decreased slowly to about 7% after 6 hours. 

The kinetics of disappearance from the circulation of intravenously administered human insulin (Fig. 6.32) is nonlinear [145]. Within a few minutes after injection, it becomes localized in the liver, heart, and kidneys, where it is rapidly metabolized. Indeed, the hepatic extraction could be as high as 70% on a single passage, whereas kidneys could account for 10-40% degradation. Enzymatic reduction of the disulfide bridges appears to be the first step in the in vivo metabolism of insulin, although this reaction appears of limited significance under in vitro conditions. 

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