Figure 4. Semilogarithmic plots of concentrations (as ng/ml of base) of
intravenously administered buprenorphine (1) in plasma against time (min) for the
1.4171 mg/kg dose in 22.85 kg dog A (Study #1, Table 2). In the bottom and middle
figures, the solid line represents the curve obtained by fitting the plasma data
to a sum of three exponentials in accordance with the equation (2):
Cp(ng/ml) = 986.3 e-0'6823 t + 491.5 e-0'02627 t
39.8 e'0-'00076 1
The middle inset is the continuation of the data and fitted curve for an extended
time scale up to 2000 min. The top inset represents the data fitted to a
4-compartment model in accordance with the equation:
Cp (ng/ml) = 1066 e
-0.77
t joo -0.0304
+ 488 e
t ^ .c -0.00426
+ 45.4 e
t
L -0.0003434 t
+ 22 e
Refer to the section "Validity of the terminal rate constant" for a discussion of
fitting of the data to 4-comartment model.