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A novel approach has been developed for the quantitative determination of circulating drug concentrations in clinical studies using dried plasma spots (DPS) on paper substrates, rather than conventional plasma samples. A quantitative bioanalytical high-pressure liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) assay has been validated using paroxetine as a tool compound (range 0.2-200 ng/mL human plasma). The assay employed simple solvent extraction of a punched disk taken from the DPS sample, followed by reversed phase HPLC separation, combined with multiple reaction monitoring mass spectrometric detection. In addition to performing routine experiments to establish the validity of the assay to internationally accepted criteria (precision, accuracy, linearity, sensitivity, selectivity), experiments are included to assess the effect of the volume of plasma spotted and the use of an indicating paper. The validated DPS approach was successfully applied to a clinical study utilizing pooled samples and a direct comparison of DPS and plasma was made (single oral dose of 37.5 mg of paroxetine).

Reliable prediction of two fundamental human pharmacokinetic (PK) parameters, systemic clearance (CL) and apparent volume of distribution (Vd), determine the size and frequency of drug dosing and are at the heart of drug discovery and development. Traditionally, estimated CL and Vd are derived from preclinical in vitro and in vivo absorption, distribution, metabolism, and excretion (ADME) measurements. In this paper, we report quantitative structure-activity relationship (QSAR) models for prediction of systemic CL and steady-state Vd (Vdss) from intravenous (iv) dosing in humans. These QSAR models avoid uncertainty associated with preclinical-to-clinical extrapolation and require two-dimensional structure drawing as the sole input. The clean, uniform training sets for these models were derived from the compilation published by Obach et al. (Drug Metab. Disp. 2008, 36, 1385-1405). Models for CL and Vdss were developed using both a support vector regression (SVR) method and a multiple linear regression (MLR) method. The SVR models employ a minimum of 2048-bit fingerprints developed in-house as structure quantifiers. The MLR models, on the other hand, are based on information-rich electro-topological states of two-atom fragments as descriptors and afford reverse QSAR (RQSAR) analysis to help model-guided, in silico modulation of structures for desired CL and Vdss. The capability of the models to predict iv CL and Vdss with acceptable accuracy was established by randomly splitting data into training and test sets. On average, for both CL and Vdss, 75% of test compounds were predicted within 2.5-fold of the value observed and 90% of test compounds were within 5.0-fold of the value observed. The performance of the final models developed from 525 compounds for CL and 569 compounds for Vdss was evaluated on an external set of 56 compounds. The predictions were either better or comparable to those predicted by other in silico models reported in the literature. To demonstrate the practical application of the RQSAR approach, the structure of vildagliptin, a high-CL and a high-Vdss compound, is modified based on the atomic contributions to its predicted CL and Vdss to propose compounds with lower CL and lower Vdss.

The importance of studying oral drug absorption is well recognized by both research facilities/institutions and the pharmaceutical industry. The use of mathematical models can represent a very profitable and indispensable tool to understand oral drug absorption. Indeed, mathematical models can verify the correctness of the mechanisms proposed to describe drug release, absorption, distribution and elimination thus reducing the number of expensive and time-consuming experiments. In this paper we develop a mathematical approach able to model both the polymeric particle mediated delivery and the gastrointestinal absorption-metabolism-excretion (ADME) of a given drug. As a model drug a poorly water-soluble drug (vinpocetine) in both the amorphous and nanocrystalline state is considered. The delivery system is obtained by drug cogrinding with a polymer (cross-linked polyvinilpyrrolidone). As the proposed mathematical model can properly fit the in vivo data on the basis of information obtained in vitro, it represents a powerful theoretical tool connecting in vitro and in vivo behavior.

A novel approach has been developed for the quantitative determination of circulating drug concentrations in clinical studies using dried blood spots (DBS) on paper, rather than conventional plasma samples. A quantitative bioanalytical HPLC-MS/MS assay requiring small blood volumes (15 microL) has been validated using acetaminophen as a tool compound (range 25 to 5000 ng/mL human blood). The assay employed simple solvent extraction of a punch taken from the DBS sample, followed by reversed phase HPLC separation, combined with selected reaction monitoring mass spectrometric detection. In addition to performing routine experiments to establish the validity of the assay to internationally accepted criteria (precision, accuracy, linearity, sensitivity, selectivity), a number of experiments were performed to specifically demonstrate the quality of the quantitative data generated using this novel sample format, namely, stability of the analyte and metabolites in whole human blood and in DBS samples; effect of the volume of blood spotted, the device used to spot the blood, or the temperature of blood spotted. The validated DBS approach was successfully applied to a clinical study (single oral dose of 500 mg or 1 g acetaminophen).

In previous papers, we have offered a strategic framework regarding metabolites of drugs in humans and the need to assess these in laboratory animal species (also termed Metabolites in Safety Testing or MIST; Smith and Obach, Chem. Res. Toxicol. (2006) 19, 1570-1579). Three main tenets of this framework were founded in (i) comparisons of absolute exposures (as circulating concentrations or total body burden), (ii) the nature of the toxicity mechanism (i.e., reversible interaction at specific targets versus covalent binding to multiple macromolecules), and (iii) the biological matrix in which the metabolite was observed (circulatory vs excretory). In the present review, this framework is expanded to include a fourth tenet: considerations for the duration of exposure. Basic concepts of pharmacology are utilized to rationalize the relationship between exposure (to parent drug or metabolite) and various effects ranging from desired therapeutic effects through to severe toxicities. Practical considerations of human ADME (absorption-distribution-metabolism-excretion) data, to determine which metabolites should be further evaluated for safety, are discussed. An analysis of recently published human ADME studies shows that the number of drug metabolites considered to be important for MIST can be excessively high if a simple percentage-of-parent-drug criterion is used without consideration of the aforementioned four tenets. Concern over unique human metabolites has diminished over the years as experience has shown that metabolites of drugs in humans will almost always be observed in laboratory animals, although the proportions may vary. Even if a metabolite represents a high proportion of the dose in humans and a low proportion in animals, absolute abundances in animals frequently exceed that in humans because the doses used in animal toxicology studies are much greater than therapeutic doses in humans. The review also updates the enzymatic basis for the differences between species and how these relate to MIST considerations.

A nonlinear model equation based on tissue composition (a content of lipids, proteins, and water) for the tissue-blood partition coefficients of compounds was further developed in this paper to account for the neutral and ionized forms of the compounds. The nonlinear model equation may be considered as the expressive form of the Hansch equation in nonlinear spaces (or multiphase system). Based on this model our nonlinear regression analysis for neutral and ionized compounds partitioning into kidney, brain, muscle, lung, liver, heart, and fat resulted in equations with high fitting power (training set: n=201, r=0.905, s=0.291, Q=0.890) and strong predictive power (test set: n=64, r=0.906, s=0.247). These results showed that the equilibrium distribution of a compound in a variety of tissues is essentially the equilibrium distribution of the compound in tissue (chemical) compositions. Neutral and ionic forms of a compound as well as in different tissue (chemical) compositions have a different mechanism of action in vivo.

In this paper, QSPR models were developed for in vivo blood-brain partitioning data (logBB) of a large data set consisting of 115 diverse organic compounds. The best model is based on three descriptors: n-octanol/water partition coefficient calculated using the SLOGP approach, logP; high-charged polar surface areas based on the Gasteiger partial charges, HCPSA, and the excessive molecular weight larger than 360, MW(360). The model bears good statistical significance, n = 78, r = 0.88, q = 0.86, s = 0.36, F = 81.5. The actual prediction potential of the model was validated through two external validation sets of 37 diverse compounds. The predicted results demonstrate that the model bears better prediction potential than many other models and can be used for logBB estimations for drug and drug-like molecules. Comparison of several logP calculation approaches suggests that logP calculated by SLOGP can be used as a significant descriptor for the prediction of molecular transport properties because SLOGP gives the most similar results with CLOGP. The QSPR model indicates that larger polar surface areas have a more negative contribution to logBB, but the absolute partial charges on the atoms surrounded by the polar surfaces should be larger than 0.10|e|. Meanwhile, tight junction membranes limit the size of hydrophilic molecules that can cross the membrane with a molecular weight of approximately 360, because when a molecule's weight is larger than 360 it shows a negative contribution to logBB. The computations of molecular surface, partial charges, logP, and logBB have been accomplished using a program called Drug-BB. Moreover, to improve the efficiency of the computations of logP, we made an extensive reparametrization of SLOGP, and the newly developed SLOGP model is only based on simple atomic addition. Further, we developed a set of parameters to calculate the topological polar surface area (TPSA), thus the high-charged topological polar surface area (HCTPSA) could be estimated from the 2D connection information of a molecule. Adopting the new strategies, the estimations of logP, HCTPSA, and logBB are only based on the topological structure of a molecule and therefore, can be used for fast screening of virtual libraries having millions of molecules.

This paper describes a graphical model for simplifying in vitro absorption, metabolism, distribution, and elimination (ADME) data analysis through the estimation of oral bioavailability (%F) of drugs in humans and other species. This model integrates existing in vitro ADME data, such as Caco-2 permeability (P(app)) and metabolic stability (percent remaining - %R) in liver S9 or microsomes, to estimate %F into groups of low, medium, or high regions. To test the predictive accuracy of our model, we examined 21 drugs and drug candidates with a wide range of oral bioavailability values, which represent approximately 10 different therapeutic areas in humans, rats, dogs, and guinea pigs. In vitro data from model compounds were used to define the boundaries of the low, medium, and high regions of the %F estimation plot. On the basis of the in vitro data, warfarin (93%), indomethacin (98%), timolol (50%), and carbamazepine (70%) were assigned to the high %F region; propranolol (26%) and metoprolol (38%) to medium %F region; and verapamil (22%) and mannitol (18%) to the low %F region. Similarly, the %F of 11 drug candidates from Elastase Inhibitor, NK1/NK2 antagonist, and anti-viral projects in rats, guinea pigs, and dogs were correctly estimated. This model estimates the oral bioavailability ranges of neutral, polar, esters, acidic, and basic drugs in all species. For a large number of drug candidates, this graphical model provides a tool to estimate human oral bioavailability from in vitro ADME data. When combined with the high throughput in vitro ADME screening process, it has the potential to significantly accelerate the processes of lead identification and optimization.

A new molecular lipoaffinity descriptor was introduced in this paper to account for the effect of molecular hydrophobicity on blood-brain barrier penetration. The descriptor was defined based on Kier and Hall's atom-type electrotopological state indices. Its evaluation requires 2-D molecular bonding information only. A multiple linear regression equation using this descriptor and molecular weight reproduces the experimental logBB values of 55 training set compounds and 11 test set compounds satisfactorily with statistical parameters nearly identical to the best models based on polar surface area and ClogP. The results indicate that the lipoaffinity descriptor defined in this paper may be a significant descriptor for molecular transport properties across lipid bilayers.

A preceding paper (Bonfanti et al. J. Med Chem.2007, 50, 4572−4584) reported the optimization of the pharmacokinetic profile of substituted benzimidazoles by reducing their tissue retention. However, the modifications that were necessary to achieve this goal also led to a significant drop in anti-RSV activity. This paper describes a molecular modeling study followed by a lead optimization program that led to the recovery of the initial potent antiviral activity and the selection of TMC353121 as a clinical candidate. [ABSTRACT FROM AUTHOR]

Signal peptide peptidase-like 2a (SPPL2a) is an aspartic intramembrane protease which has recently been shown to play an important role in the development and function of antigen presenting cells such as B lymphocytes and dendritic cells. In this paper, we describe the discovery of the first selective and orally active SPPL2a inhibitor (S)-2-cyclopropyl-N1-((S)-5,11-dioxo-10,11-dihydro-1H,3H,5H-spiro[benzo[d]pyrazolo[1,2-a][1,2]diazepine-2,1'-cyclopropan]-10-yl)-N4-(5-fluoro-2-methylpyridin-3-yl)succinamide 40 (SPL-707). This compound shows adequate selectivity against the closely related enzymes γ-secretase and SPP and a good pharmacokinetic profile in mouse and rat. Compound 40 significantly inhibited processing of the SPPL2a substrate CD74/p8 fragment in rodents at doses ≤10 mg/kg b.i.d. po. Oral dosing of 40 for 11 days at ≥10 mg/kg b.i.d. recapitulated the phenotype seen in Sppl2a knockout (ko) and ENU mutant mice (reduced number of specific B cells and myeloid dendritic cells). Thus, we believe that SPPL2a represents an interesting and druggable pharmacological target, potentially providing a novel approach for the treatment of autoimmune diseases by targeting B cells and dendritic cells. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is an endocrine disruptor frequently detected in human biofluids. Dermal absorption of BPA from thermal paper receipts occurs but BPA pharmacokinetics following dermal exposure is not understood. To compare the pharmacokinetics of dermal and dietary BPA exposure, six male participants handled simulated receipts containing relevant levels of BPA (isotope-labeled BPA-d16) for 5 min, followed by hand-washing 2 h later. Urine (0-48 h) and serum (0-7.5 h) were monitored for free and total BPA-d16. One week later, participants returned for a dietary administration with monitoring as above. One participant repeated the dermal administration with extended monitoring of urine (9 days) and serum (2 days). After dietary exposure, urine total BPA-d16 peaked within 5 h and quickly cleared within 24 h. After dermal exposure, cumulative excretion increased linearly for 2 days, and half the participants still had detectable urinary total BPA-d16 after 1 week. The participant repeating the dermal exposure had detectable BPA-d16 in urine for 9 days, showed linear cumulative excretion over 5 days, and had detectable free BPA-d16 in serum. Proportions of free BPA-d16 in urine following dermal exposure (0.71%-8.3% of total BPA-d16) were generally higher than following the dietary exposure (0.29%-1.4%). Compared to dietary BPA exposure, dermal absorption of BPA leads to prolonged exposure and may lead to higher proportions of unconjugated BPA in systemic circulation. [ABSTRACT FROM AUTHOR]

In this paper we describe the optimization of a phenotypic hit against Plasmodium falciparum, based on a trisubstituted pyrimidine scaffold. This led to compounds with good pharmacokinetics and oral activity in a P. berghei mouse model of malaria. The most promising compound (13) showed a reduction in parasitemia of 96% when dosed at 30 mg/kg orally once a day for 4 days in the P. berghei mouse model of malaria. It also demonstrated a rapid rate of clearance of the erythrocytic stage of P. falciparum in the SCID mouse model with an ED90 of 11.7 mg/kg when dosed orally. Unfortunately, the compound is a potent inhibitor of cytochrome P450 enzymes, probably due to a 4-pyridyl substituent. Nevertheless, this is a lead molecule with a potentially useful antimalarial profile, which could either be further optimized or be used for target hunting. [ABSTRACT FROM AUTHOR]

Human clinical studies conducted with LCI699 established aldosterone synthase (CYP11B2) inhibition as a promising novel mechanism to lower arterial blood pressure. However, LCI699's low CYP11B1/CYP11B2 selectivity resulted in blunting of adrenocorticotropic hormone-stimulated cortisol secretion. This property of LCI699 prompted its development in Cushing's disease, but limited more extensive clinical studies in hypertensive populations, and provided an impetus for the search for cortisol-sparing CYP11B2 inhibitors. This paper summarizes the discovery, pharmacokinetics, and pharmacodynamic data in preclinical species and human subjects of the selective CYP11B2 inhibitor 8. [ABSTRACT FROM AUTHOR]

In the present paper, we describedthe design, synthesis, SAR,and biological profile of a novel spirocyclic sulfone series of γ-secretaseinhibitors (GSIs) related to MRK-560. We utilized an additional spirocyclicring system to stabilize the active chair conformation of the parentγ-secretase inhibitors. The resulting series is devoid of theCYP2C9 inhibition liability of MRK-560. A few representative analogswere assessed in a nontransgenic animal model of Alzheimer’sdisease (AD), demonstrating reduction of amyloid-β (Aβ)in the CNS after acute oral dosing. A spirocyclic phosphonate wasidentified as the optimal ring system for both potency and pharmacokinetics.Compared to GSIs studied in the clinic, representative spirocyclicphosphonate 18a(−)features improved selectivityfor the inhibition of the PS-1 isoform of γ-secretase (33-foldvs PS-2), which may alleviate the adverse effect profile of the clinicalGSIs. [ABSTRACT FROM AUTHOR]

GatekeeperT790 M mutation in EGFR is the most prevalent factorunderlying acquired resistance. Acrylamide-bearing quinazoline derivativesare powerful irreversible inhibitors for overcoming resistance. Nevertheless,concerns about the risk of nonspecific covalent modification havemotivated the development of novel cysteine-targeting inhibitors.In this paper, we demonstrate that fluoro-substituted olefins canbe tuned to alter Michael addition reactivity. Incorporation of theseolefins into the quinazoline templates produced potent EGFR inhibitorswith improved safety and pharmacokinetic properties. A lead compound 5awas validated against EGFRWT, EGFRT790Mas well as A431 and H1975 cancer cell lines. Additionally, compound 5adisplayed a weaker inhibition against the EGFR-independentcancer cell line SW620 when compared with afatinib. Oral administrationof 5aat a dose of 30 mg/kg induced tumor regressionin a murine-EGFRL858R/T790Mdriven H1975 xenograft model.Also, 5aexhibited improved oral bioavailability andsafety as well as favorable tissue distribution properties and enhancedbrain uptake. These findings provide the basis of a promising strategytoward the treatment of NSCLC patients with drug resistance. [ABSTRACT FROM AUTHOR]

Adenosinediphosphate (ADP)-mediated platelet aggregation is signaledthrough two distinct G protein-coupled receptors (GPCR) on the plateletsurface: P2Y12and P2Y1. Blocking P2Y12receptor is a clinically well-validated strategy for antithrombotictherapy. P2Y1antagonists have been shown to have the potentialto provide equivalent antithrombotic efficacy as P2Y12inhibitorswith reduced bleeding in preclinical animal models. We have previouslyreported the discovery of a potent and orally bioavailable P2Y1antagonist, 1. This paper describes furtheroptimization of 1by introducing 4-aryl groups at thehydroxylindoline in two series. In the neutral series, 10qwas identified with excellent potency and desirable pharmacokinetic(PK) profile. It also demonstrated similar antithrombotic efficacywith less bleeding compared with the known P2Y12antagonistprasugrel in rabbit efficacy/bleeding models. In the basic series, 20c(BMS-884775) was discovered with an improved PK and liabilityprofile over 1. These results support P2Y1antagonism as a promising new antiplatelet target. [ABSTRACT FROM AUTHOR]

Evaluation of important pharmacokinetic properties such as hydrophobicity by high-throughput screening (HTS) methods is a major issue in drug discovery. In this paper, we present measurements of the chromatographic hydrophobicity index (CHI) on a subset of the French chemical library Chimiothèque Nationale (CN). The data were used in quantitative structure–property relationship (QSPR) modeling in order to annotate the CN. An algorithm is proposed to detect problematic molecules with large prediction errors, called outliers. In order to find an explanation for these large discrepancies between predicted and experimental values, these compounds were reanalyzed experimentally. As the first selected outliers indeed had experimental problems, including hydrolysis or sheer absence of expected structure, we herewith propose the use of QSPR as a support tool for quality control of screening data and encourage cooperation between experimental and theoretical teams to improve results. The corrected data were used to produce a model, which is freely available on our web server at http://infochim.u-strasbg.fr/webserv/VSEngine.html. [ABSTRACT FROM AUTHOR]

Simultaneousinactivation of p53 and hyperactivation of nuclearfactor-κB (NF-κB) is a common occurrence in human cancer.Currently, antitumor agents are being designed to selectively activatep53 or inhibit NF-κB. However, there is no concerted effortyet to deliberately design inhibitors that can simultaneously do both.This paper provided a proof-of-concept study that p53–MDM2interaction and NF-κB pathway can be simultaneously targetedby a small-molecule inhibitor. A series of pyrrolo[3,4-c]pyrazole derivatives were rationally designed and synthesized asthe first-in-class inhibitors of p53–MDM2 interaction and NF-κBpathway. Most of the compounds were identified to possess nanomolarp53–MDM2 inhibitory activity. Compounds 5qand 5ssuppressed NF-κB activation through inhibition ofIκBα phosphorylation and elevation of the cytoplasmiclevels of p65 and phosphorylated IKKα/β. Biochemical assayfor the kinases also supported the fact that pyrrolo[3,4-c]pyrazole compounds directly targeted the NF-κB pathway. Inaddition, four compounds (5j, 5q, 5s, and 5u) effectively inhibited tumor growthin the A549 xenograft model. Further pharmacokinetic study revealedthat compound 5qexhibited excellent oral bioavailability(72.9%). [ABSTRACT FROM AUTHOR]

XIAP is a key regulator of apoptosis,and its overexpression incancer cells may contribute to their survival. The antiapoptotic functionof XIAP derives from its BIR domains, which bind to and inhibit pro-apoptoticcaspases. Most known IAP inhibitors are selective for the BIR3 domainand bind to cIAP1 and cIAP2 as well as XIAP. Pathways activated uponcIAP binding contribute to the function of these compounds. Inhibitorsselective for XIAP should exert pro-apoptotic effects through competitionwith the terminal caspases. This paper details our synthetic explorationsof a novel XIAP BIR2-selective benzazepinone screening hit with afocus on increasing BIR2 potency and overcoming high in vivo clearance.These efforts led to the discovery of benzoxazepinone 40, a potent BIR2-selective inhibitor with good in vivo pharmacokineticproperties which potentiates apoptotic signaling in a manner mechanisticallydistinct from that of known pan-IAP inhibitors. [ABSTRACT FROM AUTHOR]

PEGylation of peptides and proteins has been widely used to enhance stability and reduce immunogenicity of biotherapeutics. Characterizing the degradation of these PEGylated products in biological fluids can yield essential information to support pharmacokinetic evaluations and provide clues about their in vivo properties useful for further molecular optimization. In this paper, we describe a novel and uncomplicated approach to characterize PEGylated peptides or proteins and their related degradation products in biological matrixes. The method involves direct liquid chromatography/mass spectrometry (LC/MS) analysis of animal sera containing low nanograms to low micrograms per milliliter of PEGylated product with or without an acetonitrile precipitation sample treatment. Applying the methodology to analyze the model PEGylated peptides, 20K PEGylated-Pancreatic Polypeptide analogue (PPA) and 20K PEGylated-glucagon, we elucidated the decomposition pathways occurring in animal sera. The data provided direct evidence of cleavages within the peptide backbone. The identified degradation products were unambiguously confirmed by tandem mass spectrometry with high-energy C-trap dissociation (HCD) analysis, followed with in-source fragmentation. Additional spiking studies demonstrated nearly full recovery of PEGylated products, linear detection when the spiked concentration of PEGylated product was =1000 ng/mL, and a low ng/ mL limit of quantitation (LOQ). [ABSTRACT FROM AUTHOR]

The serum clearance rate of therapeutic antibodies is important as it affects the clinical efficacy, required dose, and dose frequency. The glycosylation of antibodies has in some studies been shown to have an impact on the elimination rates in vivo. Monitoring changes to the glycan profiles in pharmacokinetics studies can reveal whether the clearance rates of the therapeutic antibodies depend on the different glycoforms, thereby providing useful information for improvement of the drugs. In this paper, a novel method for glycosylation analysis of therapeutic antibodies in serum samples is presented. A microfluidic compact-disc (CD) platform in combination with MALDI-MS was used to monitor changes to the glycosylation profiles of samples incubated in vitro. Antibodies were selectively purified from serum using immunoaffinity capture on immobilized target antigens. The glycans were enzymatically released, purified, and finally analyzed by MALDI-TOF-MS. To simulate changes to glycan profiles after administration in vivo, a therapeutic antibody was incubated in serum with the enzyme α1-2,3 mannosidase to artificially reduce the amount of the high mannose glycoforms. Glycan profiles were monitored at specific intervals during the incubation. The relative abundance of the high mannose 5 glycoform was clearly found to decrease and, simultaneously, that of high mannose 4 increased over the incubation period. The method can be performed in a rapid, parallel, and automated fashion for glycosylation profiling consuming low amounts of samples and reagents. This can contribute to less labor work and reduced cost of the studies of therapeutic antibodies glycosylation in vitro and in vivo. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The phosphoinositide 3-kinase family catalyzes the phosphorylationof phosphatidylinositol-4,5-diphosphate to phosphatidylinositol-3,4,5-triphosphate,a secondary messenger which plays a critical role in important cellularfunctions such as metabolism, cell growth, and cell survival. Ourefforts to identify potent, efficacious, and orally available phosphatidylinositol3-kinase (PI3K) inhibitors as potential cancer therapeutics have resultedin the discovery of 4-(2-((6-methoxypyridin-3-yl)amino)-5-((4-(methylsulfonyl)piperazin-1-yl)methyl)pyridin-3-yl)-6-methyl-1,3,5-triazin-2-amine(1). In this paper, we describe the optimization of compound 1, which led to the design and synthesis of pyridyltriazine 31, a potent pan inhibitor of class I PI3Ks with a superiorpharmacokinetic profile. Compound 31was shown to potentlyblock the targeted PI3K pathway in a mouse liver pharmacodynamic modeland inhibit tumor growth in a U87 malignant glioma glioblastoma xenograftmodel. On the basis of its excellent in vivo efficacy and pharmacokineticprofile, compound 31was selected for further evaluationas a clinical candidate and was designated AMG 511. [ABSTRACT FROM AUTHOR]

Since their discovery at the end of the previous millennium,carbonnanotubes (CNTs) have been the object of thousands of papers describingtheir applications in fields ranging from physics to electronics,photonics, chemistry, biology, and medicine. The development of chemicalapproaches to modify their graphitic sidewalls enabled the generationof poly(ethylene glycol) (PEG)-modified CNTs and their explorationin multiple biomedical applications. Studies at the cellular and organismlevel revealed that PEG-modified CNTs have favorable pharmacokineticand toxicology profiles. Recently, PEG-modified CNTs have been successfullytested in preclinical studies in the fields of oncology, neurology,vaccination, and imaging, suggesting that they are well suited forthe generation of novel multifunctional nanodrugs. Here we will reviewpublished data about the application of PEG-modified CNTs as in vitroand in vivotherapeutic and imagingtools and describe what is known about the interaction between PEG-modifiedCNTs and biological systems. Although several pieces of the puzzleare still missing, we will also attempt to formulate a preliminarystructure–function model for PEG-modified CNT cellular trafficking,disposition, and side effects. [ABSTRACT FROM AUTHOR]

Post-translational modifications, in particular glycosylation, represent critical structural attributes that govern both the pharmacodynamic and pharmacokinetic properties of therapeutic glycoproteins. To guarantee safety and efficacy of recombinant therapeutics, characterization of glycosylation present is a regulatory requirement. In the current paper, we applied a multidimensional strategy comprising a shallow anion exchange gradient in the first dimension, followed by analysis using the recently introduced 1.7 μm HILIC phase in the second dimension for the comprehensive separation of complex N-glycans present on the European Biological Reference Preparation (BRP) 3 erythropoietin standard. Tetra-antennary glycans with multiple sialic acids and poly-N-acetyl lactosamine extensions were the most abundant oligosaccharides present on the molecule. Site-specific glycan analysis was performed to examine microheterogeneity. Tetra-antennary glycans with up to four sialic acids and up to five poly-N-acetyl lactosamine extensions were observed at asparagine 24 and 83, while biantennary glycans were the major structures at asparagine 38. The combined AEC x UPLC HILIC allows for the rapid and comprehensive analysis of complex N-glycosylation present on therapeutic glycoproteins, such as BRP3 erythropoietin. [ABSTRACT FROM AUTHOR]

This paper demonstrates the generation of systemically deliverable layer-by-layer (LbL) nanoparticles for cancer applications. LbL-based nanoparticles designed to navigate the body and deliver therapeutics in a programmable fashion are promising new and alternative systems for drug delivery, but there have been very few demonstrations of their systemic delivery in vivo due to a lack of knowledge in building LbL nanofilms that mimic traditional nanoparticle design to optimize delivery. The key to the successful application of these nanocarriers in vivo requires a systematic analysis of the influence of film architecture and adsorbed polyelectrolyte outer layer on their pharmacokinetics, which has thus far not been examined for this new approach to nanoparticle delivery. Herein, we have taken the first steps in stabilizing and controlling the systemic distribution of multilayer nanoparticles. Our findings highlight the unique character of LbL systems; the electrostatically assembled nanoparticles gain increased stability in vivo with larger numbers of deposited layers, and the final layer adsorbed generates a critical surface cascade, which dictates the surface chemistry and biological properties of the nanoparticle. This outer polyelectrolyte layer dramatically affects not only the degree of nonspecific particle uptake, but also the nanoparticle biodistribution. For hyaluronic acid (HA) outer layers, a long blood elimination half-life (∼9 h) and low accumulation (∼10–15% recovered fluorescence/g) in the liver were observed, illustrating that these systems can be designed to be highly appropriate for clinical translation. [ABSTRACT FROM AUTHOR]

The paper reports on the development of an accurate hydrophilic liquid interaction chromatography tandem mass spectrometry (HILIC-MS/MS) based stable isotope dilution analysis for the simultaneous quantitation of the food-derived bioactive pyridines trigonelline, nicotinic acid, nicotinamide, and N-methylpyridinium, as well as their key metabolites nicotinamide-JV-oxide, N-methylni-cotinamide, JV-memyI-2-pyridone-5-carboxamide, JV-methyl-4-pyridone-5-carboxamide, and N-methyl-2-pyridone-5-carboxylic acid in human plasma and urine. Precision of the stable isotope dilution analysis (SIDA) was 1.9% and 11.9% relative standard deviation (n = 6), and accuracy was between 92.4% and 113.0%. The lower limit of quantitation (LLOQ) was 50 fmol (10 pmol/mL) injected onto the column for all analytes with the exception of JV-methyl-2-pyridone-5-carboxylic acid and JV-methyl 2 pyridone-5-carboxamide, for which an LLOQ of 100 fmol (20 pmol/mL) was found. The method was applied to monitor the plasma appearance and urinary excretion and to determine pharmacokinetic parameters of the bioactive pyridines as well as their metabolites in a clinical human intervention study with healthy volunteers (six women, seven men) after oral administration of 350 inL of a standard coffee beverage. Trigonelline plasma levels increased from 160 nmol/Lto maximum concentrations of 5479 (males) or 6547 nmol/L (females), and N-methylpyridinium plasma levels raised from virtually complete absence to maximum values of 777 (females) or 804 nmoI/L (males) within 2-3 and 1 -2 h after coffee consumption, respectively. The high plasma levels of JV-methjipyridinium found after coffee consumption clearly demonstrate for the first time that this cation is entering the vascular system, which is the prerequisite for biological in vivo effects claimed for that compound. In contrast, the coffee intervention did not significantly influence the plasma concentrations of N-methyl-2-pyridone-5-carboxa-mide and JV-methyl-4-pyridone-5-carboxamide, the major niacin metabolites. Within 8 h after coffee intervention, an urinary excretion of 57.4 ± 6.9% of trigonelline and 69.1 ± 6.2% of N-methylpyridinium was found for the male volunteers, whereas females excreted slightly less with 46.2 ± 7.4% and 61.9 ± 12.2% of these pyridines. [ABSTRACT FROM AUTHOR]

17β-Estradiol (E2), the most potent female sex hormone, stimulates the growth of mammary tumors and endometriosis via activation of the estrogen receptor α (ERα). 17β-Hydroxysteroid dehydrogenase type 1 (17β-HSD1), which is responsible for the catalytic reduction of the weakly active estrogen estrone (E1) into E2, is therefore discussed as a novel drug target. Recently, we have discovered a 2,5-bis(hydroxyphenyl) oxazole to be a potent inhibitor of 17β-HSD1. In this paper, further structural optimizations were performed: 39 bis(hydroxyphenyl) azoles, thiophenes, benzenes, and aza-benzenes were synthesized and their biological properties were evaluated. The most promising compounds of this study show enhanced IC 50values in the low nanomolar range, a high selectivity toward 17β-HSD2, a low binding affinity to ERα, a good metabolic stability in rat liver microsomes, and a reasonable pharmacokinetic profile after peroral application. Calculation of the molecular electrostatic potentials revealed a correlation between 17β-HSD1 inhibition and the electron density distribution. [ABSTRACT FROM AUTHOR]