TABLE 3

IC50 determinations and Ki estimation for the inhibition of bilirubin glucuronidation in human liver microsomes (HLM) and cDNA-expressed UGT1A1 a


HIV Inhibitor

IC50 Valuesb

Ki Estimatesc
UGT1A1
HLM
UGT1A1
HLM
μM
Atazanavir 2.4 2.5 1.2 1.3
Indinavir 87 68 44 34
Saquinavir 7.3 5.0 3.7 2.5
Nelfinavir
8.4
2.7
4.2
1.4
  • a Human cDNA-expressed UGT1A1 in lymphoblast cells.

  • b Positive control was β-estradiol (UGT1A1).

  • c Ki was estimated based on Ki = 1/2 × IC50 when [S] = Km, assuming a competitive inhibition.