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Receptor Interacting Protein 2 (RIP2) kinase inhibitors have been reported for therapeutic opportunities in inflammatory bowel diseases such as Ulcerative Colitis and Crohn's disease. During lead optimization, team identified 4-aminoquinoline series and several compounds from this series were investigated in rat and dog pharmacokinetic studies. While compounds such as GSKA and GSKB demonstrated acceptable pharmacokinetics in rat and dog, further progression of these compounds was halted due to adverse findings in advanced safety studies. Structurally similar analogues incorporating polarity at C-7 position of 4-aminoquinoline resulted in identification of GSKC - GSKF. Interestingly, following oral administration to rat at similar low dose, GSKC - GSKF demonstrated significantly low systemic drug exposure compared to GSKA and GSKB (3-17-fold difference). However, in dog, dose normalized oral systemic exposure for GSKC - GSKF was comparable to GSKA and GSKB (within 2-fold). A series of studies were conducted to understand the disconnect which highlighted that an intrinsic reduction in permeability and high P-glycoprotein (P-gp) efflux ratio for C-7 substituted analogues were driving pharmacokinetic disconnect between rat and dog. Oral absorption was minimally impacted in dog by P-gp mediated efflux compared to rat because the leakier gastrointestinal tract in dog likely overcomes this effect.

The purpose of this investigation was to compare selected pharmacokinetic (PK) parameters obtained by cassette and discrete dosing of compounds in rats. The concordance of PK properties obtained by the two dosing strategies was evaluated for 116 compounds representing various therapeutic programs and diverse chemical structures. The correspondence between cassette- and discrete-dosing-derived PK properties was examined semiquantitatively and qualitatively. For semiquantitative comparison, compounds with cassette-to-discrete PK parameter ratios between 0.5 and 2 (inclusive) were considered to be in agreement. For qualitative comparison, compounds were divided into three categories (low, moderate, and high) based on the value of the PK parameter; compounds that fell into the same category following cassette and discrete dosing were considered to be in agreement. Of the 116 compounds evaluated, 89%, 91%, 80%, and 91% of the compounds were semiquantitatively equivalent for the intravenous PK parameters of clearance (CL), volume of distribution (Vdss), terminal elimination plasma half-life (HL), and mean residence time (MRT), respectively, whereas 79%, 80%, 79%, and 72% were qualitatively similar for CL, Vdss, MRT, and terminal elimination plasma HL, respectively. Following oral administration, bioavailability concordance was 72% when assessed qualitatively and 78% when determined semiquantitatively. Results from these analyses indicate that a cassette dosing strategy is a viable approach to screen compounds for PK properties within a drug discovery setting. © 2011 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:3862–3874, 2011

The efficacy of n-lauryl-beta-D-maltopyranoside, (dodecylmaltoside, DDM) as a permeability-enhancer for tiludronate and cromolyn (BCS Class III, water-soluble compounds with oral bioavailability5%) was evaluated in Caco-2 cell monolayers and rat intestinal sacs. In Caco-2 cells samples were collected over a 5-h period and transepithelial resistance (TEER) was measured concurrently. In rat intestinal sacs, samples of the test compounds and marker (Lucifer Yellow) were collected over a 40 min period; accumulation in the serosal fluid and intestinal tissue was measured. At lower concentration DDM had no effect on cromolyn permeability and a marginal increase was observed at higher concentration. Tiludronate permeability in the presence of DDM showed greater enhancement as compared to cromolyn. At higher concentration DDM appeared to cause permanent damage to the cell monolayer (irreversible change in TEER). In the intestinal tissue, DDM caused increased tissue accumulation of test compounds. This indicated that transport was not restricted to the paracellular route and damage to the intestinal tissue could not be ruled out. Based on the results obtained in this study it can be concluded that at concentrations that are non-toxic DDM appears to have a limited use to improve the oral absorption of cromolyn and tiludronate.

We have designed and synthesized a novel series of pyrrolidinones as progesterone receptor partial agonists. Compounds from this series had improved AR selectivity, rat pharmacokinetic properties, and in vivo potency compared to the lead compound. In addition, these compounds had improved selectivity against hERG channel inhibition.

This work describes the development of potent and selective human Urotensin-II receptor antagonists starting from lead compound 1, (3,4-dichlorophenyl)methyl{2-oxo-2-[3-phenyl-2-(1-pyrrolidinylmethyl)-1-piperidinyl]ethyl}amine. Several problems relating to oral bioavailability, cytochrome P450 inhibition, and off-target activity at the kappa opioid receptor and cardiac sodium channel were addressed during lead development. hUT binding affinity relative to compound 1 was improved by more than 40-fold in some analogs, and a structural modification was identified which significantly attenuated both off-target activities.

The prediction of human pharmacokinetics from preclinical species is an integral component of drug discovery. Recent studies with a 103-compound dataset suggested that scaling from monkey pharmacokinetic data tended to be the most accurate method for predicting human clearance. Additionally, interrogation of the two-dimensional molecular properties of these molecules produced a set of associations which predict the likely extrapolative outcome (success or failure) of preclinical data to project human pharmacokinetics. However, a limitation of the previous analyses was the relative paucity of data for typical "discovery-like" molecules (molecular weight >300 and/or clogP >3). The objective of this investigation was to generate preclinical data required for extension of this dataset for additional discovery-like molecules and determine whether the aforementioned findings continue to apply for these molecules. In vivo nonrodent intravenous pharmacokinetic data were generated for 13 molecules, and data for 8 additional molecules were obtained from the literature. Additionally, the various scaling methodologies and molecular features analysis were applied to this new dataset to predict human pharmacokinetics. Whereas the predictive accuracies demonstrated across all of the various methodologies were lower for this higher clearance compound dataset, scaling from monkey liver blood flow continued to be an accurate methodology, and human volume of distribution was similarly well predicted regardless of scaling methodology. Lastly, application of the molecular feature associations, particularly data-dependent associations, afforded an improved predictivity compared with the liver blood flow scaling approaches, and provides insight into the extrapolation of high clearance compounds in the preclinical species to human.

During this century, several investigators reported that certain viruses, metals, drugs, and other solutes could bypass systemic circulation and enter the brain and/or cerebrospinal fluid directly following nasal administration. Although evidence clearly suggests that the olfactory epithelium and its olfactory cells play a major role, little is known about the mechanisms of direct transport of solutes into the brain. An overview of what is known about these mechanisms may aid in further research in this field, including studies of direct drug delivery to the central nervous system. This review, in addition to summarizing the literature to date, clearly describes the intricate association of the anatomical features involved in direct entry of solutes into the brain following nasal administration. To aid in the understanding of the possible routes a solute can take after nasal administration, the anatomy of the olfactory epithelium and surrounding tissues is described, and a detailed scheme delineating the emerging pathways is presented. Techniques used in delineating these pathways and studies supporting a particular pathway are discussed in greater detail. Finally, some factors influencing the direct transport of solutes to the cerebrospinal fluid and brain are summarized.

The previously reported pyrrolidine class of progesterone receptor partial agonists demonstrated excellent potency but suffered from serious liabilities including hERG blockade and high volume of distribution in the rat. The basic pyrrolidine amine was intentionally converted to a sulfonamide, carbamate, or amide to address these liabilities. The evaluation of the degree of partial agonism for these non-basic pyrrolidine derivatives and demonstration of their efficacy in an in vivo model of endometriosis is disclosed herein.

This Letter discloses a series of 2-aminothiadiazole amides as selective EP 3 receptor antagonists. SAR optimization resulted in compounds with excellent functional activity in vitro. In addition, efforts to optimize DMPK properties in the rat are discussed. These efforts have resulted in the identification of potent, selective EP 3 receptor antagonists with excellent DMPK properties suitable for in vivo studies.

The lead serum and glucocorticoid-related kinase 1 (SGK1) inhibitors 4-(5-phenyl-1H-pyrrolo[2,3-b]pyridin-3-yl)benzoic acid (1) and {4-[5-(2-naphthalenyl)-1H-pyrrolo[2,3-b]pyridin-3-yl]phenyl}acetic acid (2) suffer from low DNAUC values in rat, due in part to formation and excretion of glucuronic acid conjugates. These PK/glucuronidation issues were addressed either by incorporating a substituent on the 3-phenyl ring ortho to the key carboxylate functionality of 1 or by substituting on the group in between the carboxylate and phenyl ring of 2. Three of these analogs have been identified as having good SGK1 inhibition potency and have DNAUC values suitable for in vivo testing.

Two classes of amino acid-derived heterocyclic progesterone receptor ligands were developed to address the metabolic issues posed by the dimethyl amide functionality of the lead compound (1). The tetrazole-derived ligands behaved as potent partial agonists, while the 1,2,4-triazole ligands behaved as potent full agonists.

Lead compound 1 was successfully redesigned to provide compounds with improved pharmacokinetic profiles for this series of human urotensin-II antagonists. Replacement of the 2-pyrrolidinylmethyl-3-phenyl-piperidine core of 1 with a substituted N-methyl-2-(1-pyrrolidinyl)ethanamine core as in compound 7 resulted in compounds with improved oral bioavailability in rats. The relationship between stereochemistry and selectivity for hUT over the κ-opioid receptor was also explored.

This study was conducted to comprehensively evaluate the performance of various allometric scaling methods for the prediction of human clearance. Allometric scaling was used to predict clearance for 103 compounds, for which clearance data in the rat, dog, monkey, and humans were available. Allometry was performed using all three preclinical species and with combinations of any two species. The methods employed included standard allometry and various correction factors, including brain weight, maximum lifespan potential, and glomerular filtration. Scaling was performed on all compounds universally and on segregated subsets based on allometric exponent, clearance, physicochemical property, or route of elimination. 776 allometric combinations with 27,313 individual outcomes were performed. A predicted-to-observed clearance ratio of 0.5 to twofold was preselected as the criterion for predictive success. The success rate of allometric scaling ranged from 18 to 53%; none of the correction factors resulted in substantially improved predictivity. Furthermore, none of the methods attempted in this study achieved a success rate greater than that observed by simply estimating human clearance based on monkey hepatic extraction. Prospective allometric scaling, with or without correction factors, represents a suboptimal technique for estimating human clearance based on in vivo preclinical data.