Evaluation Of New Chemical Entities Research Articles

Physicochemical susceptibility of SARS-CoV-2 to disinfection and physical approach of prophylaxis.

The transmission control of the newly emerged severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is the most effective strategy by the absence of its specified vaccine or drug. Although the aerosol mediated transmission of SARS‐CoV‐2 has been confirmed, the physicochemical treatment of the biotic and abiotic objects is still the most promising approach in its infection control. The front line of the most effective disinfecting compounds on SARS‐CoV‐2 implies to be sodium hypochlorite, ethanol, hydrogen peroxide, quaternary ammonium compounds, and phenolic compounds, respectively. However, widely used compounds of alkyldimethylbenzylammonium chloride (benzalkonium chloride) biguanides (chlorhexidine) have not shown the multitude load reduction in less than 10 minutes. The susceptibility of SARS‐CoV‐2 to physical treatment follows the pattern of heat, acidity, and UV radiation. Rather all of the mentioned physical or chemical treatments, target the envelope proteins of the coronavirus mainly by impairing its entry to host cells. The anti‐SARS‐CoV‐2 activity of combinatorial physicochemical treatments or evaluation of new chemical entities or physical treatments such as microwave irradiation still needs to be explored. Therefore, the development of a reliable decontamination protocol for SARS‐CoV‐2 demands revealing its stability pattern study vs a spectrum of single and combinatorial physicochemical parameters.

Technological Advances in Preclinical Drug Evaluation: The Role of -Omics Methods.

Preclinical drug development is an essential step in the drug development process where the evaluation of new chemical entities occurs. In particular, preclinical drug development phases include deep analysis of drug candidates' interactions with biomolecules/targets, their safety, toxicity, pharmacokinetics, metabolism by use of assays in vitro and in vivo animal assays. Legal aspects of the required procedures are well-established. Herein, we present a comprehensive summary of current state-of-the art approaches and techniques used in preclinical studies. In particular, we will review the potential of new, -omics methods and platforms for mechanistic evaluation of drug candidates and speed-up of the preclinical evaluation steps.

Investigation of Lung Pharmacokinetic of the Novel PDE4 Inhibitor CHF6001 in Preclinical Models: Evaluation of the PreciseInhale Technology.

Preclinical evaluation of new chemical entities (NCEs) designed to be administered by inhalation route requires lung administration to rodents, especially in the discovery phase. Different administration methods have been used until now, but more efforts are required to obtain controlled and reproducible lung deposition when only small amounts of neat powder material are available. The PreciseInhale platform used in the present study enables well-controlled powder aerosol exposures with only small amounts of micronized neat material, providing data on inhalation pharmacokinetic (PK) of NCEs at a very early stage. The DustGun aerosol technology uses compressed air to generate a respirable aerosol from milligram-amounts of powder that is delivered to one animal at a time. The new methodology was used to investigate the inhalation PK and lung retention in the rat of the novel Chiesi PDE4 inhibitor CHF6001 in three exposure models of the PreciseInhale platform: nose-only, intratracheally intubated rat, and the isolated, ventilated, and perfused rat lung. Results were compared with data from two other pulmonary delivery systems commonly used in preclinical studies: liquid instillation and powder insufflation. Administration of micronized CHF6001 using the PreciseInhale system yielded lung exposures in the same range as the other tested devices, but the reproducibility in lung deposition was improved. The initial amount of CHF6001 in lungs at the first sampling time point was close to the predetermined target dose. Tracheal deposition with PreciseInhale (0.36 ± 0.22 μg) was significantly less than with other tested delivery systems: PennCentury (23.7 ± 3.2 μg) and Airjet (25.6 ± 7.2 μg). The PreciseInhale platform enabled the administration of CHF6001 powder with good accuracy and reproducibility, with low tracheal deposition. The new platform can be used at an early discovery stage to obtain inhalatory PK data for respirable aerosols of neat NCE powder without excipients and with minimal use of dry powder formulation work.

Evaluation of New Chemical Entities as Substrates of Liver Transporters in the Pharmaceutical Industry: Response to Regulatory Requirements and Future Steps

This article discusses the evaluation of drug candidates as hepatic transporter substrates. Recently, research on the applications of hepatic transporters in the pharmaceutical industry has improved to meet the requirements of the regulatory guidelines for the evaluation of drug interactions. To identify the risk of transporter-mediated drug-drug interactions at an early stage of drug development, we used a strategy of reviewing the in vivo animal pharmacokinetics and tissue distribution data obtained in the discovery stage together with the in vitro data obtained for regulatory submission. In the context of nonclinical evaluation of new chemical entities as medicines, we believe that transporter studies are emerging as a key strategy to predict their pharmacological and toxicological effects. In combination with the recent progress in systems approaches, the estimation of effective concentrations in the target tissues, by using mathematical models to describe the transporter-mediated distribution and elimination, has enabled us to identify promising compounds for clinical development at the discovery stage.

CNS Adverse Effects: From Functional Observation Battery/Irwin Tests to Electrophysiology.

This chapter describes various approaches for the preclinical assessment of drug-induced central nervous system (CNS) adverse effects. Traditionally, methods to evaluate CNS effects have consisted of observing and scoring behavioral responses of animals after drug is administered. Among several behavioral testing paradigms, the Irwin and the functional observational battery (FOB) are the most commonly used assays for the assessment of CNS effects. The Irwin and FOB are considered good first-tier assays to satisfy the ICH S7A guidance for the preclinical evaluation of new chemical entities (NCE) intended for humans. However, experts have expressed concern about the subjectivity and lack of quantitation that is derived from behavioral testing. More importantly, it is difficult to gain insight into potential mechanisms of toxicity by assessing behavioral outcomes. As a complement to behavioral testing, we propose using electrophysiology-based assays, both in vivo and in vitro, such as electroencephalograms and brain slice field-potential recordings. To better illustrate these approaches, we discuss the implementation of electrophysiology-based techniques in drug-induced assessment of seizure risk, sleep disruption, and cognitive impairment.

Synthesis and Pharmacological Evaluation of New Chemical Entities from Ibuprofen as Novel Analgesic Candidates.

Non-steroidal anti-inflammatory drugs (NSAIDs) are the first choice of drugs that are normally used for the treatment of pain and inflammation. Ibuprofen (I) and its analogues as the most widely used NSAIDs have been synthesized in recent years. In an effort to establish new candidates with improved analgesic properties, derivatives (II-VII) with substituted aromatic as well as aliphatic moieties were synthesized in this experiment and evaluated in formalin test with rats. The results were compared to ibuprofen and control groups. Findings indicated that derivatives with new alkylphenyl rings (VI and VII) had some similar or more analgesic activities relative to the control and ibuprofen groups, respectively; which could be justified as to more alkyl and phenyl groups instead of p-isobutylphenyl moiety in I.

Synthesis and Pharmacological Evaluation of New Chemical Entities Based on Paracetamol and Their Ibuprofen Conjugates as Novel and Superior Analgesic and Anti-Inflammatory Candidates

p-Aminophenol had been evaluated in the past as an analgesic–antipyretic drug, but its N-acetylated derivative acetaminophen (paracetamol) was found to be the most suitable therapeutically. Acetaminophen is still one of the most popular drugs, which is frequently used for the relief of acute and chronic pain. In this study, new analogs of paracetamol with dimethyl and ethyl substitutions in the phenyl moiety and sulfonamide, which was modified by inserting morpholine, were synthesized (compounds 4 and 5). Then, their conjugated compounds with ibuprofen (6) were synthesized (8 and 9) and the analgesic and anti-inflammatory activities of these new drugs (4, 5, 8, 9) were evaluated in formalin-induced edema test (as a model of acute and chronic chemical pain and also paw edema inflammation) on rats. The results were compared to paracetamol, ibuprofen (as standards), and control (saline) groups. Results showed that the new synthesized derivatives exhibit higher analgesic and anti-inflammatory effects compared to acetaminophen alone for compounds 4, 5, 8 and 9 or ibuprofen for compounds 4, 8 and 9. Moreover, it was concluded that chemical-structural binding of the potent synthesized drugs (4 and 5) with ibuprofen (6) produced new superior anti-nociceptive and anti-inflammatory drugs (8 and 9).

Discovery and early evaluation of new chemical entities

Discovery and early evaluation of new chemical entities

Efficacy of linezolid against Staphylococcus aureus in different rodent skin and soft tissue infections models

<p>Linezolid is approved for complicated and uncomplicated skin and soft tissue infections. We have evaluated the efficacy of this drug in murine as well as in rat skin and soft tissue infection models using <em>Staphylococcus aureus</em> ATCC and clinical strains. In thigh infection model the dose of linezolid required for more than 1 log<sub>10</sub> kill from baseline inoculum in neutropenic mice and rats was 100 mg/kg and 50 mg/Kg BW bid /day, respectively, which was 5 and 4 folds more than that in immunocompetent animals, respectively. Dose required to achieve 1 log<sub>10</sub> killing was similar against different strains of <em>S. aureus </em>in immunocompetent mouse thigh infection model. However, in murine groin abscess infection model, a dose of 100 mg/kg, b.i.d/day of linezolid produce static effect in 2 days, but revealed to be superior in 4 days treatment and showed approximately 1 log<sub>10</sub> killing from base line inoculums. Based upon pharmacokinetic profile, a 24-h AUC/MIC required for linezolid efficacy in murine groin abscess model was 91.5 for the strain used in this study. As linezolid is taken as a gold standard drug in the evaluation of new chemical entity, this data could be useful for comparing the preclinical efficacy of new anti-MRSA agents.</p>

Evaluation of Compound Activity Against Hepatitis C Virus in Replicon Systems

Described in this unit are protocols for evaluation of new chemical entities for activity against hepatitis C virus (HCV) using HCV replicon systems. While agents designed to target NS3 protease, NS3 helicase, and NS5B RNA polymerase can be evaluated in biochemical assays, it is important to confirm their inhibitory effect on HCV RNA replication using HCV replicon systems, especially since replication involves many components besides these enzymes. Screening of compound libraries using replicon systems has led to the discovery of replication inhibitors, which act through different viral targets.

Mouse models of human bladder cancer as a tool for drug discovery.

Muscle-invasive bladder cancer is a deadly condition in dire need of effective new treatments. This unit contains a description of mouse models suitable for the evaluation of potential new therapies. Included is a genetically engineered mouse model of bladder cancer generated by the delivery of an adenovirus expressing Cre recombinase into the bladder lumen. Also described is an orthotopic mouse model created by the instillation of human bladder tumor cells into the bladder lumen of immune deficient mice. Protocols are also provided on the use of these models for the preclinical evaluation of new chemical entities, with mTOR inhibitors shown as an example.

Tissue-Specific mRNA Expression Profiles of Drug-Metabolizing Enzymes and Transporters in the Cynomolgus Monkey

Pairs of forward and reverse primers and TaqMan probes specific to each of 19 drug-metabolizing enzymes (cytochrome P450s, UDP-glucuronosyltransferases, glutathione S-transferases, and sulfotransferases) and 5 transporters (ABC and SLC transporters) in the cynomolgus monkey were prepared. The expression level of each target mRNA was analyzed in total RNA obtained from three specimens of various cynomolgus monkey tissues (adrenal gland, brain, heart, kidney, large intestine, liver, lung, pancreas, prostate, small intestine, spleen, testis, and thymus) by real-time reverse transcription PCR using an Applied Biosystems 7500 Fast Real-Time PCR System. The data obtained in the present study provide useful information on tissue-specific profiles of the expression of these target mRNAs in the cynomolgus monkey, and the results are expected to be valuable in establishing drug metabolism- and transporter-mediated screening systems using the cynomolgus monkey for the evaluation of new chemical entities in new drug development.

Sub one minute inhibition assays for the major cytochrome P450 enzymes utilizing ultra‐performance liquid chromatography/tandem mass spectrometry

The measurement of cytochrome P450 (CYP450) isoenzyme inhibition is often done during evaluation of new chemical entities in drug discovery. Typical assay protocol consists of multiple CYP450 probe substrates incubated with selected drug candidates and CYP450. Results of the assay, the amount of probe substrate metabolite formed with respect to control, are used to determine the level of interaction. Liquid chromatography utilizing columns packed with sub-2-micron particles have been shown to provide up to 8X faster analysis time and 3X increases in sensitivity over traditional high-performance liquid chromatography (HPLC). The work presented here shows the development of a high-throughput, sub-2-micron particle LC method coupled with tandem quadrupole mass spectrometry for the rapid analysis of six CYP450 probe substrate metabolites in 30s.

Comparative QSAR studies on PAMPA/modified PAMPA for high throughput profiling of drug absorption potential with respect to Caco-2 cells and human intestinal absorption

Despite the dramatic increase in speed of synthesis and biological evaluation of new chemical entities, the number of compounds that survive the rigorous processes associated with drug development is low. Thus, an increased emphasis on thorough ADMET (absorption, distribution, metabolism, excretion and toxicity) studies based on in vitro and in silico approaches allows for early evaluation of new drugs in the development phase. Artificial membrane permeability measurements afford a high throughput, relatively low cost but labor intensive alternative for in vitro determination of drug absorption potential; parallel artificial membrane permeability assays have been extensively utilized to determine drug absorption potentials. The present study provides comparative QSAR analysis on PAMPA/modified PAMPA for high throughput profiling of drugs with respect to Caco-2 cells and human intestinal absorption.

Ambulatory Cardiac Monitoring (ACM) is Important in the Evaluation of New Chemical Entities

Clinical Pharmacology & Therapeutics (2003) 73, P31–P31; doi:

Rapid determination of pharmacokinetic properties of new chemical entities: in vivo approaches.

There is a continuing need for increased throughput in the evaluation of new chemical entities in terms of their pharmacokinetic (PK) parameters as part of new drug discovery. This review summarizes various approaches that have been used to increase throughput in this area. The article divides the approaches into two areas: assay enhancement and sample reduction.

High-throughput cytochrome P450 inhibition screening via cassette probe-dosing strategy. IV. Validation of a direct injection on-line guard cartridge extraction/tandem mass spectrometry method for simultaneous CYP3A4, 2D6 and 2E1 inhibition assessment.

A highly efficient direct injection on-line guard cartridge extraction/tandem mass spectrometry (DI-GCE/MS/MS) method has been validated for high-throughput evaluation of cytochrome P450 (CYP) 3A4, 2D6 and 2E1 inhibition potential via cassette dosing of midazolam, dextromethorphan and chlorzoxazone using human hepatic microsomes and 96-well microtiter plates. Microsomal incubations were terminated with formic acid, centrifuged, and the resulting supernatants were injected for analysis by DI-GCE/MS/MS. Due to the novel use of an extremely short C(18) guard cartridge (4 mm in length), this method exhibits several advantages such as no sample preparation, excellent on-line extraction, short run time (2.5 min), and minimized source contamination and performance deterioration. The DI-GCE/MS/MS method demonstrates acceptable accuracy and precision for the simultaneous quantification of 1'-hydroxymidazolam, dextrorphan and 6-hydroxychlorzoxazone in microsomal incubations. The inhibition potential of CYP3A4, 2D6 and 2E1 has been evaluated using their known selective inhibitors. The IC(50) values measured by the cassette dosing approach (high-throughput) are consistent with those observed by an individual dosing regimen (conventional) and are all in good agreement with the literature values. The results suggest that the cassette probe-dosing strategy may provide an in vitro approach to minimize cost while maximizing throughput of CYP inhibition evaluation of new chemical entities in support of drug discovery and development.

Toxicology Support ADME Studies for Safety Evaluation of New Chemical Entity.

The objectives of pharmacokinetics and metabolic studies in drug safety evaluation is the drug absorption, the duration of drug exposure and the effects of multiple dose regimen on the pharmacokinetics in test animal species. There are many examples of drug to show little or no toxic event at extremely high dose level, which originate in low absorption or low bioavailability of the drug. A complicating situation can arise when the pharmacokinetic profile of the drug changes during repeated dosing due to such factors as enzyme induction, saturation of metabolism, accumulation of drug in the tissue, and renal excretion process. The toxic effect could also changed their pharmacokinetics during a toxicity testing. It is important to monitor a drug level during the toxicity testing. When toxicity cause depends on toxic metabolites or reactive intermediates, the plasma concentration of unchanged drug are difficult to correlate to the toxic efect. It is indispensable to evaluate the metabolic pathways and metabolic clearance of a durg under similar conditions of toxicity testing. These data may be useful for the interpretation of toxicological finding and their relevance to clinical safety evaluation. Stereoselective pharmacokinetics and metabolic studies should be evaluated because of differences on the pharmacokinetics and metabolism of each enantiomer. Most of dihydropyridine calcium antagonists have one or more chiral centre, and the pharmacological activity between the enantiomers for these durg is known to be markedly different. The stereoselective pharmacokinetics of these drugs in animals, healthy subjects and patients should evaluated during the development process. Enantiomer-enantiomer interaction, enantiomeric inversion and the stereochemical aspects of pharmacokinetic drug interactions in these drugs should also be studied.

Globalisation of drug regulation and drug regulators in developing countries

Drug regulatory agencies in developing countries are often relatively small and poorly funded; they are therefore necessarily heavily dependent upon the experience gained and the assessments carried out by larger national agencies elsewhere. This applies both to the basic efficacy/safety evaluation of new chemical entities and the quality evaluation of products based on well-known active components and also to other acts of major agencies, e.g., with respect to unexpected problems arising with a drug or the correction of inadmissible advertising. To date, far too little information on these matters is available to the agencies of developing countries. In part this is due to lack of formalised international arrangements, but the agencies which should be able to provide this information are also sometimes poorly structured to do so, and in some instances serious doubts exist as to the reliability of regulatory work carried out elsewhere, whether this relates to evaluation of drugs, inspection of manufacturing plants or other matters. These problems are often compounded by the fact that agencies in developing countries may have an insufficient legal infrastructure to carry out their task to the full.