Assessment of the renal toxicity of novel anti-inflammatory compounds using cynomolgus monkey and human kidney cells.

PF1, an anti-inflammatory drug candidate, was nephrotoxic in cynomolgus monkeys in a manner that was qualitatively comparable to that observed with the two previous exploratory drug candidates (PF2and PF3). Based on the severity of nephrotoxicity, PF1 ranked between the other two compounds, withPF2 inducing mortality at all doses and PF3 eliciting only mild nephrotoxicity. To further characterize nephrotoxicity in monkeys and enable direct comparisons with humans, primary cultures of proximal tubular (PT) cells from monkey and human kidneys were used as in vitro tools, using lactate dehydrogenase release as the biomarker of cytotoxicity. In both human and monkey PT cells, PF2was by far the most cytotoxic compound of the three drugs. PF1 exhibited modest cytotoxicity at the highest concentration tested in human PT cells but none in monkey kidney cells whereas PF3 exhibited the reverse pattern.Because these drugs are organic anions, mechanistic studies using human organic anion transporters 1 and 3 (hOAT1 andhOAT3) transfected cell lines were pursued to evaluate the potential of these compounds to interact with these transporters. All three drugs exhibited high affinity for hOAT3 (PF1 exhibited the lowest IC50 of 6M) but only weakly interacted with hOAT1 (with no interaction found for PF2). PF2 was a strong hOAT3 (not hOAT1) substrate, whereas PF1 and PF3 were substrates for both hOAT1 and hOAT3.Upon pretreatment of monkeys with the OAT substrate probenecid, PF3 systemic exposure (AUC) and half-life (t1/2) increased approximately 2-fold whereas clearance (CL) and volume of distribution (Vdss) decreased, as compared to naïve monkeys. This indicated that PF3 competed with probenecid for hOAT1 and/or hOAT3mediated elimination of PF3. Thus, hOAT1 and/or hOAT3 may be responsible for the uptake of this series of drugs in renal PT cells, which may directly or indirectly lead to the observed nephrotoxicity in vivo.

(2R)-2-methylchromane-2-carboxylic acids: discovery of selective PPARalpha agonists as hypolipidemic agents.

A SAR study was conducted on chromane-2-carboxylic acid toward selective PPARalpha agonisim. As a result, highly potent, and selective PPARalpha agonists were discovered. The optimized compound 43 exhibited robust lowering of total cholesterol levels in hamster and dog animal models.

In vitro and in vivo trans-esterification of 1-[2(R)-(2-amino-2-methylpropionylamino)-3-(1H-indol-3-yl)propionyl]-3(S)-benzyl-piperidine-3-carboxylic acid ethyl ester and the effects of ethanol on its pharmacokinetics in rats.

PURPOSE: To investigate the in vitro trans-esterification of 1-[2(R)-(2-amino-2-methylpropionylamino)-3-(1H-indol-3-yl)propionyl]-3(S)-benzyl-piperidine-3-carboxylic acid ethyl ester (compound A) and to determine the effects of ethanol on its in vivo pharmacokinetics in male Sprague-Dawley rats. METHODS: The effects of deuterated [d5]ethanol on the hydrolysis and trans-esterification of compound A in rat plasma and rat liver microsomes in the presence or absence of bis(p-nitrophenyl) phosphate (BNPP), a carboxylesterase inhibitor, were investigated. Following an oral pretreatment with deuterated ethanol in conjunction with an intravenous dose of compound A to rats, the pharmacokinetics of compound A and deuterated compound A were evaluated. RESULTS: It was observed that the amount of deuterated compound A generated increased with increasing amounts of deuterated ethanol in incubates, whereas the amount of hydrolyzed product (compound B) decreased. BNPP inhibited both the hydrolysis and the trans-esterification of compound A. Furthermore, the pharmacokinetics of compound A in rats receiving ethanol was altered, such that the plasma clearance decreased by 1.5-fold and the elimination rate constant decreased by 2-fold. Deuterated compound A was determined, confirming that trans-esterification proceeded in vivo; approximately one third of the intravenous dose of compound A underwent trans-esterification. CONCLUSIONS: In the presence of ethanol, compound A underwent trans-esterification catalyzed by carboxylesterases. Ethanol pretreatment resulted in a decrease in the in vivo clearance of compound A mainly due to trans-esterification with ethanol.