Ki-Wha Lee

Design and Synthesis of Potential Inhibitors of the Ergosterol Biosynthesis as Antifungal Agents

A series of azolylmethyloxolane derivatives with modified sterol side-chain structures, designed as potential dual functional inhibitors of cytochrome P450 14alpha-demethylase (14DM) and delta24-sterol methyltransferase (24-SMT) based on the common characteristic features of 24-aminosterols and azole antifungal agents, were synthesized and evaluated for their antifungal activities and inhibitory activities of 14DM and 24-SMT. Among these compounds, imidazolylmethyloxolane derivatives 28a and 28b showed potent in vitro antifungal activities comparable to those of itraconazole. However, the in vitro bioactivities have not been linearly translated into in vivo protection data for some unknown reasons.

Oral and topical pharmacokinetic studies of a novel TRPV1 antagonist, PAC-14028 in rats and minipigs using liquid chromatography/tandem mass spectrometric method

PAC-14028 ((E)-N-((R)-1-(3,5-difluoro-4-methanesulfonylamino-phenyl)-ethyl)-3-(2-propyl-6-trifluoromethyl-pyridine-3-yl)-acrylamide) is a novel and potent transient receptor potential vanilloid type I (TRPV1) antagonist. We developed and validated a rapid, sensitive and selective liquid chromatography/tandem mass spectrometric method for determination of PAC-14028 in rat and minipig plasma. After protein precipitation PAC-14028 and internal standard (methylated analog, PAC-14026) were separated on a Symmetry C(18) column (4.6 mm × 75 mm, 3.5 μm) with an isocratic mobile phase, acetonitrile: water (8:2, v/v) containing 0.2% formic acid and monitored by electrospray positive ionization with multiple reaction monitoring mode (PAC-14028, 492→156; IS, 506→156, m/z). The calibration curve was linear over the range of 1.0-500 ng/ml (r(2)>0.999) and lower limit of quantitation (LLOQ) was 1 ng/ml. The precision and accuracy were within ± 15% and the stability was acceptable during bench-top, auto-sampler, 3 freeze-thaw cycles and 4-week storage in a freezer at -80°C. This method was successfully applied to the intravenous, oral and topical pharmacokinetic studies of PAC-14028 in rats and minipigs, which showed comparable pharmacokinetic parameters (T1/2, 2.1h and 3.8h; F%, 52.7% and 64.2% for rats and minipigs, respectively). Percutaneous absorption of PAC-14028 was negligible after topical application (F% 0.2-1.7%).