Figure 75. Semilogarithmic plots of the buprenorphine conjugate (M,
metabolite) remaining to be excreted in bile/urine versus time (sigma
minus plot) in accordance with equation 20. a) Semilogarithmic fitting
of the post-infusion urine data to a sum of two exponentials for the
1.889 mg/kg IV infusion dose of the metabolite in the
non-bile-cannulated dog F (Study #13, Table 7). The estimated hybrid
rate constants were 0.0229/min (half-life = 30 min) and 0.0012/min
(half-life = 578 min). b) Sigma minus plot of the post-infusion biliary
excretion of the metabolite for the 0.5153 mg/kg IV infusion dose of the
metabolite in the bile-cannulated dog G (Study #14, Table 7). The
apparent rate constant for this monoexponential fit was 0.0051/min
(half-life = 139 min). In the same dog G, the sigma minus plot of the
post-infusion urinary excretion of the metabolite could be fitted to a
sum of 2 exponentials. The estimated hybrid rate constants were
0.0216/min (half-life = 32 min) and 0.005/min (half-life = 141 min).