Article Figures & Data
Figures
- Figure 1
Structure of delavirdine.
- Figure 2
HPLC-radiochemical profiles of microsomal delavirdine metabolism among species. [14C]Delavirdine (10 μM) was incubated with microsomal samples (0.5 mg of protein/ml) shown for 20 min in the presence of NADPH. Reactions were quenched with acetonitrile and analyzed by HPLC with radiochemical detection.
- Figure 3
Delavirdine metabolism by S9 fraction from human jejunum.
Samples treated as in fig. 2, except S9 protein was 10 mg/ml.
- Figure 4
Mass spectral fragmentation of delavirdine and metabolites.
Upper left, delavirdine; lower left, desalkyl delavirdine; upper right, MET-7a; lower right, MET-7.
- Figure 5
Selected ion monitoring of delavirdine metabolites using HPLC-ESI-MS.
- Figure 6
Eadie-Hofstee plots of delavirdine desalkylation by various hepatic microsomal preparations.
Data represent a single experiment.
- Figure 7
Correlation analysis of delavirdine metabolism with human CYP3A activity.
Delavirdine desalkylation was measured at 50 μM substrate among human liver microsomal samples (N = 23; 0.8 mg of protein/ml; 4-min incubation). Indicator CYP activities were determined by established methods. Sample-to-sample variation in rates of marker activities and delavirdine desalkylation were correlated. Rates are nmol/min/mg microsomal protein. Results represent mean of duplicate determinations.
- Figure 8
Effect of specific inhibitors on delavirdine desalkylation by human liver microsomes or jejunum S9.
Incubations were set up with pooled human liver microsomes (0.8 mg/ml) or jejunum S9 (10 mg/ml), 30 μM delavirdine, NADPH, and inhibitors at concentrations shown. Furafylline and TAO were preincubated with the metabolically complete system for 15 min before addition of delavirdine. Reactions were quenched after 10 min, and desalkylation was assayed by HPLC. Results are mean of duplicate determinations. Control values: human liver microsomes, 0.30 nmol/min/mg protein; jejunum S9, 0.0050 nmol/min/mg protein.
- Figure 9
HPLC-radiochemical profiles of delavirdine metabolism by cDNA-expressed P450 isoforms. [14C]Delavirdine (50 μM) was incubated with microsomal samples (0.5 or 1.0 mg protein/ml) for 30 min in the presence of NADPH.
Reactions were quenched with acetonitrile and analyzed by HPLC with radiochemical detection.
Tables
- Table 1
Kinetic evaluation of delavirdine metabolism by liver microsomes from several species
Species Condition KM(μM) Vmax (nmol/min/mg) Vmax/KM (ml/min/mg) Human Pooled 6.8 ± 0.8 0.44 ± 0.01 64 Rat Male 9.9 ± 1.0 0.40 ± 0.1 40 Monkey Cynomolgus 4.4 ± 0.6 0.60 ± 0.02 135 Dog Beagle 12.6 ± 1.9 0.07 ± 0.01 6 -
Initial rate of delavirdine desalkylation was determined.KM and Vmax were estimated by nonlinear curve fitting based on a single experiment using 8–11 substrate concentrations.
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- Table 2
Correlation analysis of delavirdine metabolism (MET-7 and desalkyl-DLV) with testosterone 6β-hydroxylation by human liver microsomes (N = 10)
Test. 6β-OH MET-7 (5) Desalkyl-DLV (5) MET-7 (50) Test. 6β-OH 1 MET-7 (5) 0.92 1 Desalkyl-DLV (5) 0.94 0.96 1 MET-7 (50) 0.95 0.98 0.96 1 Desalkyl-DLV (50) 0.99 0.96 0.97 0.98 -
Values in parentheses denote delavirdine substrate concentration.
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- Table 3
Effect of quinidine on delavirdine desalkylation catalyzed by human liver microsomes
Subject CYP2D6 DextromethorphanO-Demethylation3-a Delavirdine Desalkylation3-a Quinidine (μM) 0 1 10 HL 11 Normal 630 439 371 (85)3-b 360 (82)3-b HL 22 Normal 380 89 74 (83) 71 (80) HL 24 Normal 280 75 59 (79) 60 (79) HL 16 Deficient 70 168 160 (95) 154 (91) HL 18 Deficient 30 829 791 (95) 764 (92) HL 19 Deficient 60 174 171 (98) 167 (96) -
Microsomal protein (0.5 mg/ml) from the donors shown was incubated with delavirdine (40 μM) in the presence of quinidine at the concentrations shown. Reaction was allowed to proceed for 5 min, followed by assay of desalkyl delavirdine. Values are mean of duplicate determinations.
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↵3-a Rates are pmol/min/mg protein.
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↵3-b Values in parentheses represent percentage of control (no quinidine).
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