1. The metabolism of KBH-A40, a novel δ-lactam-based histone deacetylase (HDAC) inhibitor, was investigated in vitro using human liver microsomes and serum. After 60-min incubation in human liver microsomes with β-nicotinamide adenine dinucleotide phosphate (NADPH) or uridine diphosphate glucuronic acid (UDPGA), the residual KBH-A40 was 90.6% ± 5.1% and 28.9% ± 2.0% (t1/2 = 26 min), respectively, suggesting that KBH-A40 is likely predominantly metabolized by glucuronidation, rather than by cytochrome P450 (CYP)-mediated oxidation. Consistently, KBH-A40 glucuronide was the only metabolite identified following incubations of KBH-A40 with human liver microsomes in the presence of both NADPH and UDPGA. 2. KBH-A40 was not notably degraded when incubated with human serum for 60 min. In contrast, KBH-A40 was rapidly hydrolysed to its carboxylic acid form in rat serum (t1/2 = 13 min). 3. Taken collectively, the results suggest that KBH-A40 is likely metabolized in man predominantly by glucuronidation of its hydroxamic acid moiety, with negligible biotransformation elsewhere in the molecule.
Bibliographical noteFunding Information:
The present work was supported by a grant from the KRIBB Research Initiative Program and the Brain Korea 21 Project. H. M. Kim and S. J. Oh contributed equally to this work.
All Science Journal Classification (ASJC) codes
- Health, Toxicology and Mutagenesis