Predicted Hepatic Clearance ml/min/kg (N=6) a
Freshd 56.1% 56.6% Drug Enzymes Responsible for
Metabolism Observed in vivo ClSYS ml/min/kg 34.7%
Single Donorb Drugs Ranked Correctly e:
Drugs Ranked Correctly (excluding primary 2D6 substrates) e:
Average:
RSD:
a) Predicted hepatic clearance was calculated using 4 time points (0, 30, 60, & 120 minutes).
b) Cryopreserved single donor, Lot TPZ was purchased from In Vitro Technologies
c) Cryopreserved 10 donor pool, Lot KDN was purchased from In Vitro Technologies
d) Fresh Hepatocytes were purchased from In Vitro Technologies, Tissue Transformation Technologies, and Cellz Direct
e) Ranking was based on high, medium, or low stability. Red indicates an incorrect ranking with systemic clearance.
Table 2. Comparison of Predicted Hepatic Clearance Values for Various Human Hepatocyte Preparations with Observed In Vivo Systemic
Observed In Vivo CL (mL/min/kg)
Predicted CL (mL/min/kg)
Single Donor
10 Donor Pool
Fresh
Figure 5. In Vitro - In Vivo Clearance Correlations
Based on these results, we have decided to initiate a screening paradigm
of initially evaluating compounds using a single donor of cryopreserved
hepatocytes, followed by assessing compounds of interest with fresh
hepatocytes on a monthly basis. In this manner, we can screen compounds
for metabolic stability using the same lot of hepatocytes and draw
comparisons over time for similar chemical series. And we would also
reduce the liabilities associated from screening with a single donor of
cryopreserved hepatocytes.
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