Chemical reactivity of acyl glucuronides (AGs) is believed to be involved in the toxicity of carboxylic acid-containing drugs. Both direct and immune-mediated toxicity have been suggested as possible mechanisms of toxicity; however, it remains unclear. In the present study, we performed assays of half-lives, peptide adducts, and immunostimulation to evaluate the potential risk of AGs of 21 drugs and analyzed the relationship to the toxic category. AGs of all withdrawn drugs tested in this study showed short half-lives and peptide adducts formation, but so did those of several safe drugs. In contrast, only AGs of withdrawn and warning drugs induced interleukin-8 (IL-8) in human peripheral blood mononuclear cells (hPBMCs). Using a DNA microarray assay, we found that zomepirac AG induced the mRNAs of 5 genes, including IL-8 in hPBMCs. In addition, withdrawn and warning drugs were distinguished from safe drugs by an integrated score of relative mRNA expression levels of 5 genes. The immunostimulation assay showed higher sensitivity, specificity, and accuracy compared with other methods. In preclinical drug development, the evaluation of the reactivity of AGs using half-lives and peptide adducts assays followed by the evaluation of immunostimulation by highly reactive AGs using hPBMCs can contribute to improved drug safety.

1. Raloxifene-6-glucuronide (R6G) is a substrate of rat multidrug resistance-associated protein 2 (Mrp2), a transporter responsible for biliary excretion of organic anions. 2. Pharmacokinetic modeling of R6G in Eisai hyperbilirubinemic rats (EHBRs), hereditary Mrp2-deficient rats, and wild-type Sprague-Dawley rats (SDRs) indicated that reduction in not only biliary excretion but also hepatic uptake of R6G influenced low clearance in EHBRs. 3. An integration plot study demonstrated that the hepatic uptake of R6G was 66% lower in EHBRs than that in SDRs. A reduction was observed for the other Mrp2 substrate Valsartan (95% lower) but not for estradiol-17β-glucuronide (E217βG). This variation may be associated with the difference in substrate specificity of transporters and/or inhibition of hepatic uptake of organic anions by endogenous substances such as bilirubin glucuronides. 4. In conclusion, incidental alteration of the hepatic uptake of organic anions should be considered as an explanation of their enhanced systemic exposure in EHBRs.

Dipeptidyl peptidase IV (DPP-4) inhibition is suitable mechanism for once daily oral dosing regimen because of its low risk of hypoglycemia. We explored linked bicyclic heteroarylpiperazines substituted at the γ-position of the proline structure in the course of the investigation of l-prolylthiazolidines. The efforts led to the discovery of a highly potent, selective, long-lasting and orally active DPP-4 inhibitor, 3-[(2S,4S)-4-[4-(3-methyl-1-phenyl-1H-pyrazol-5-yl)piperazin-1-yl]pyrrolidin-2-ylcarbonyl]thiazolidine (8g), which has a unique structure characterized by five consecutive rings. An X-ray co-crystal structure of 8g in DPP-4 demonstrated that the key interaction between the phenyl ring on the pyrazole and the S2 extensive subsite of DPP-4 not only boosted potency, but also increased selectivity. Compound 8g, at 0.03 mg/kg or higher doses, significantly inhibited the increase of plasma glucose levels after an oral glucose load in Zucker fatty rats. Compound 8g (teneligliptin) has been approved for the treatment of type 2 diabetes in Japan.

Raloxifene is extensively glucuronidated in humans, effectively reducing its oral bioavailability (2%). It was also reported to be glucuronidated in preclinical animals, but its effects on the oral bioavailability have not been fully elucidated. In the present study, raloxifene and its glucuronides in the portal and systemic blood were monitored in Gunn rats deficient in UDP-glucuronosyltransferase (UGT) 1A, Eisai hyperbilirubinemic rats (EHBRs), which hereditarily lack multidrug resistance-associated protein (MRP) 2, and wild-type rats after oral administration. The in vitro-in vivo correlation (IVIVC) of four UGT substrates (raloxifene, biochanin A, gemfibrozil, and mycophenolic acid) in rats was also evaluated. In Gunn rats, the product of fraction absorbed and intestinal availability and hepatic availability of raloxifene were 0.63 and 0.43, respectively; these values were twice those observed in wild-type Wistar rats, indicating that raloxifene was glucuronidated in both the liver and intestine. The ratio of glucuronides to unchanged drug in systemic blood was substantially higher in EHBRs (129-fold) than in the wild-type Sprague-Dawley rats (10-fold), suggesting the excretion of raloxifene glucuronides caused by MRP2. The IVIVC of the other UGT substrates in rats displayed a good relationship, but the oral clearance values of raloxifene and biochanin A, which were extensively glucuronidated by rat intestinal microsomes, were higher than the predicted clearances using rat liver microsomes, suggesting that intestinal metabolism may be a great contributor to the first-pass effect. Therefore, evaluation of intestinal and hepatic glucuronidation for new chemical entities is important to improve their pharmacokinetic profiles.

A naphthalene compound was chosen as lead compound to develop a new series of fibrinogen receptor antagonists. Eight new compounds with different condensed heterocyclic parts were prepared and their in vitro activities were evaluated. 5-Amidinobenzofuran compound 2, 6-amidinobenzothiophene 7, and 5-amidinofuro[2,3-b]pyridine 8 were more active than lead compound 1. Molecular orbital calculation studies suggested the presence of a preferred spatial orientation between the amidine and the carboxylic acid.

The synthesis and design using molecular modeling techniques for non-peptide, low molecular weight novel fibrinogen receptor (glycoprotein IIb/IIIa: Gp IIb/IIIa) antagonists, is reported. We used a highly potent serine protease inhibitor, Nafamostat, having an amidinonaphthyl unit as the starting compound. The compounds 4-(6-amidino-2-naphthylaminocarbonyl)phenoxyacetic acid (5a) and 4-(6-amidino-2-naphthalenecarboxamido)phenoxyacetic acid (5b) inhibited adenosin-5'-diphospate (ADP)-induced aggregation of human platelet-rich plasma (PRP) with IC50 values of 0.05 and 0.07 microM, respectively, and had lost their ability to inhibit a variety of serine proteases, including thrombin, factor Xa, plasmin and trypsin.

A novel series of platelet receptor glycoprotein (Gp) IIb/IIIa antagonists with condensed heterocycles as their basic core was synthesized. In an in vitro assay, trans-4-(5-amidinobenzofuran-2-carboxamido)cyclohexyloxyacetic+ ++ acid 17e and trans-3-[4-(5-amidinobenzofuran-2- carboxamido)cyclohexyl]propionic acid 17f produced marked inhibitions with IC50 values of 0.018 and 0.006 microM, respectively in a human platelet adenosin-5'-diphospate (ADP)-induced aggregation assay; they also exhibited a wide spectrum of inhibition toward major aggregation agonists (ADP, collagen, thrombin, PMA (tumor promoter) and arachidonic acid). These compounds were > 2-3 orders of magnitude more effective in inhibiting platelet aggregation than human umbilical vein endothelial cell (HUVEC) binding. The oral administration of 10 mg/kg of either 17e and 17f to guinea pig, resulted in a 60% inhibition of ex vivo platelet aggregation after 5 h. Oral administration of ethyl trans-4-(5-amidinoben-zofuran-2- carboxamido)cyclohexyloxyacetate 18e (10 mg/kg) resulted in 80% inhibition of platelet aggregation in dogs for 6 h after oral administration with a return to baseline by 24 h. Ethyl trans-3-[4-(5-amidinobenzofuran-2-carboxamido)cyclohexyl]propionat e 18f (AR0598) produced 80% inhibition for 5 h after oral administration. Prodrug 18e showed a good profile in dogs with a long duration of action. 18e (AR0510) was selected as suitable clinical candidate for development as an orally active antithrombotic agent.

Nouveau compose d'acide carboxylique a noyau fusionne represente par la formule generale (I) (dans laquelle chaque symbole est tel que defini dans la specification) ou sel de ce compose acceptable en pharmacologie; composition medicinale contenant ce compose, et son utilisation en medecine. Ce compose et ce sel presentent un excellent antagonisme GPIIb/IIIa contre les mammiferes, y compris l'homme, peuvent etre administres oralement, presentent une longue duree de vie dans le sang et une faible toxicite, ainsi que des effets secondaires limites. Ils peuvent etre utilises avantageusement dans la prevention ou le traitement des maladies thrombotiques.

The previous paper reported on the synthesis and pharmacological evaluation of N-(6-amino-3-pyridyl)-N'-bicycloalkyl-N"-cyanoguanidine derivatives, from among which three compounds were selected as potent potassium-channel openers. In the present study, selected compounds were tested for antagonism of potassium-induced contraction of rat aorta, hypotensive activity in normotensive rats, and diuretic activity in spontaneously hypertensive rats. This led to further evaluation of compound (+/-)-10 and selection of (+)-N-(6-amino-3-pyridyl)-N'- [(1S,2R,4R)-bicyclo- [2.2.1]hept-2-yl]-N"-cyanoguanidine ((+)-10) (AL0670) for development as an antihypertensive agent. Although AL0670 is regarded as a pinacidil-type K(+)-channel opener, it showed different pharmacological and conformational profiles from pinacidil.

Several approaches to functionalize the cephalotaxine skeleton based on the Pummerer reaction and Moriarty oxidation are described.

A stereoselective total synthesis of (±)-cephalotaxine (1) has been achieved. Palladium-catalyzed [3+2] cycloaddition of 2-(trimethylsilylmethyl)-2-propenyl acetate to the nitrostyrene 7 gave the methylenecyclopentane 6, which was converted into the α-sulfinylacetamide 19. Treatment of 19 either with trifluoroacetic anhydride in dichloromethane at room temperature or with p-toluenesulfonic acid in boiling 1, 2-dichloroethane gave the benzazepinone 20 in good yield, and this was transformed to (±)-1 via Hanaoka's key intermediate 4.

Diels-Alder reaction of methyl (E)-3-(1H-imidazol-4-yl)propenoates 2, 3a-c and (E)4-(2-nitroethenyl)-1H-imidazoles 3d,e with 2,3-dimethyl-1.3-butadiene, cyclopentadiene, and cyclohexa-1,3-diene gave the corresponding cycloadducts 6-9.

(+/-)-D-Homocephalotaxine (2), an unnatural analogue of cephalotaxine, has been synthesized by a synthetic sequence involving an acid-catalyzed cyclization of the alpha-sulfinylacetamide 8 as a key step.