Figure 21. Sard logarithmic plots of the amounts of the unchanged buprenorpine (1)
remaining to be excreted in urine versus time (sigma minus plot) in accordance
with equation 20. a) Semilogarithmic fitting of the initial urine data up to 100
min for the 1.4171 mg/kg IV bolus dose of buprenorphine in dog A, Study #1. An
apparent rate constant of 0.0176/min (half-life = 39 min) was obtained, b) Fitting
of the sigma minus plot of buprenorphine in urine of dog B, Study #2 at 1.6369
mg/kg dose of buprenorphine to a sum of two exponentials. The estimated hybrid
rate constants were 0.026/min (half-life = 27 min) and 0.00176/min (half-life =
390 min), c) Sigma minus plot of urinary excretion of buprenorphine for the 1.2023
mg/kg dose of buprenorphine in dog C, Study #4. The apparent terminal phase rate
constant for the monoexponential fitting was 0.0017/min (half-life = 400 min), d)
The fitted sigma minus plot of buprenorphine in urine of dog C at 1.439 mg/kg IV
bolus dose of buprenorphine, Study #5, to a sum of two exponentials. The estimated
apparent rate constants were 0.00695/min (half-life = 100 min) and 0.000287/min
(half-life = 2412 min) respectively.