Inhibition of cytochrome P450 enzymes by saturated and unsaturated fatty acids in human liver microsomes, characterization of enzyme kinetics in the presence of bovine serum albumin (0.1 and 1.0% w/v) and in vitro - in vivo extrapolation of hepatic clearance.
The objective of the study was to determine the effect of fatty acids on CYP enzymes and the effect of BSA on intrinsic clearance of probe substrates. The inhibitory effect of thirteen fatty acids including saturated, mono-unsaturated and polyunsaturated fatty acids on CYP enzymes, kinetic parameters and intrinsic clearance values of nine CYP marker probe substrate reactions in the absence and presence of BSA (0.1 and 1.0% w/v) were characterized in human liver microsomes. The results demonstrate that most of the unsaturated fatty acids showed marked inhibition towards CYP2C8 mediated amodiaquine N-deethylation followed by inhibition of CYP2C9 and CYP2B6 mediated activities. The addition of 0.1% BSA in the incubation markedly improved the unbound intrinsic clearance values of probe substrates by reducing the Kmvalues with little or no effect on maximal velocity. The addition of BSA (0.1 and 1.0% w/v) did not influence the unbound intrinsic clearance of marker reactions for CYP2A6, and CYP3A4 enzymes. The addition of 0.1% w/v BSA is sufficient to determine the intrinsic clearance of marker probe reactions by metabolite formation approach. The predicted hepatic clearance values for the substrates using the well-stirred model, in the presence of BSA (0.1% BSA), are comparable to the in vivo hepatic clearance values.
Drug Metabolism and Pharmacokinetics, Suven Life Sciences Ltd, Jeedimetla, Hyderabad, India.
Raghava Choudary
RC
Palacharla
Drug Metabolism and Pharmacokinetics, Suven Life Sciences Ltd, Jeedimetla, Hyderabad, India.
Venkatesham
V
Uthukam
Drug Metabolism and Pharmacokinetics, Suven Life Sciences Ltd, Jeedimetla, Hyderabad, India.
Arunkumar
A
Manoharan
Drug Metabolism and Pharmacokinetics, Suven Life Sciences Ltd, Jeedimetla, Hyderabad, India.
Ranjith Kumar
RK
Ponnamaneni
Biopharmaceutical Research, Suven Life Sciences Ltd, Pashamylaram, Medak, India.
Nagasurya Prakash
NP
Padala
Biopharmaceutical Research, Suven Life Sciences Ltd, Pashamylaram, Medak, India.
Rajesh Kumar
RK
Boggavarapu
Drug Metabolism and Pharmacokinetics, Suven Life Sciences Ltd, Jeedimetla, Hyderabad, India.
Gopinadh
G
Bhyrapuneni
Biopharmaceutical Research, Suven Life Sciences Ltd, Pashamylaram, Medak, India.
Devender Reddy
DR
Ajjala
Discovery Research, Suven Life Sciences Ltd, Banjara Hills, Hyderabad, India. Electronic address: nvsrk@suven.com.
Ramakrishna
R
Nirogi
D065607:Cytochrome P-450 Enzyme Inhibitors / Q000494:pharmacology*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005227:Fatty Acids / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008862:Microsomes, Liver / Q000187:drug effects* / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000378:metabolism*
D065607:Cytochrome P-450 Enzyme Inhibitors; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D012710:Serum Albumin, Bovine; D003577:Cytochrome P-450 Enzyme System
Bovine serum albumin (BSA); CYP450 enzymes; Enzyme inhibition; Fatty acids; Hepatic clearance; In vitro – In vivo extrapolation (IVIVE); Intrinsic clearance; Michaelis-Menten kinetics; Well-stirred model