Figure 18. Semilogarithmic plots of the plasma concentrations (ng/ml) of
metabolite (M) against time (min) for the 1.2023 mg/kg IV bolus dose of
buprenorphine (1) in 22.5 kg dog C, Study #4. The solid line represents the curve
obtained by fitting the plasma data of M to a sum of three exponentials in
accordance with the equation (2):
~ -0.602 t _C1 -0.0346 t Q -0.00191 t
Cp (ng/ml) = 1781 e + 361 e + 40.8 e
The inset is a continuation of the data and the fitted curve for an extended time
scale up tp 1500 min. The terminal half-life was estimated to be 363 min. This
value had much error due to limited analytical sensitivity, low dose and lack of
sufficient number of terminal phase plasma points.