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The drug discovery process is a rocky path that is full of challenges, with the result that very few candidates progress from hit compound to a commercially available product, often due to factors, such as poor binding affinity, off-target effects, or physicochemical properties, such as solubility or stability. This process is further complicated by high research and development costs and time requirements. It is thus important to optimise every step of the process in order to maximise the chances of success. As a result of the recent advancements in computer power and technology, computer-aided drug design (CADD) has become an integral part of modern drug discovery to guide and accelerate the process. In this review, we present an overview of the important CADD methods and applications, such as in silico structure prediction, refinement, modelling and target validation, that are commonly used in this area. [ABSTRACT FROM AUTHOR]

Paracetamol (PCM) has two well-documented polymorphic forms at room temperature; monoclinic Form I is more stable than the other orthorhombic Form II. Form II exhibits improved tabletting properties compared to Form I due to low shearing forces; however, difficulties in its manufacture have limited its use in industrial manufacture. Previous studies have found that the introduction of a co-former to form co-crystals would allow the PCM molecule to exist in a conformation similar to that of the orthorhombic form while being more stable at room temperature. Experimental charge density analysis of the paracetamol-4,40-bipyridine (PCM-44BP) co-crystal system, and its constituent molecules, has been carried out to examine the forces that drive the formation and stabilisation of the co-crystal, while allowing PCM to maintain a packing motif similar to that found in Form II. It is hoped studies on this well-known compound will help apply the knowledge gained to other drug molecules that are less successful. The PCM molecules in the co-crystal were found to exhibit similar packing motifs to that found in Form I, however, intercalation of the 44BP molecule between the PCM layers resulted in a shallower angle between molecular planes, which could result in the required lateral shear. Topological analysis identified more weak interactions in the co-crystal compared to the individual molecules, thus allowing for greater stability as evidenced by the lattice energies. Weak interactions in the PCM-44BP co-crystal were found to range in strength from 4.08-84.33 kJ·mol-1, and this variety allowed the PCM-44BP planes to be held together, while a weak π-π interaction (15.14 kJ·mol-1) allowed lateral shear to occur, thus mimicking the planes found in Form II PCM and offering the possibility of improved tabletting properties. A comparison of integrated atomic charges between partitions of the PCM molecules in the single and co-crystal found that the hydroxyl and amide groups were involved in greater hydrogen bonding in the co-crystal, resulting in a charge redistribution across the molecule evidenced by a larger molecular dipole moment (μ = 12.34D). These findings, in addition to the co-crystal having the largest lattice energy, form a potential basis with which to predict that the co-crystal exhibits improved solubility and stability profiles. It is anticipated that these findings will contribute to improvements in the formulation and other physical properties of PCM and other pharmaceutical compounds. [ABSTRACT FROM AUTHOR]

The experimental electron density distribution (EDD)in 8-hydroxyquinoline cocrystallized with salicylic acid, 1, has been determined from a multipole refinement of high-resolutionX-ray diffraction data collected at 100 K. The experimental EDD iscompared with theoretical densities resulting from high-level ab initioand BHandH calculations using Atoms in Molecules theory. 1crystallizes in the triclinic crystal system, and the asymmetricunit consists of a neutral salicylic acid molecule, a salicylate anion,and an 8-hydroxyquinolinium cation exhibiting a number of inter- andintramolecular hydrogen bonds and π–π interactions.Topological analysis reveals that π–π interactionsare of the “closed-shell” type, characterized by ratherlow and flat charge density. In general, the agreement of the topologicalvalues (ρbcpand ∇2ρbcp) between experiment and theory is good, with mean differencesof 0.010 e Å–3and 0.036 e Å–5, respectively. The energetics of the π–π interactionshave been estimated, and excellent agreement is observed between therelative energy and the strength of π-stacking derived fromthe Espinosa approach, with an average difference of only 4.4 kJ mol–1. [ABSTRACT FROM AUTHOR]

Bacterial infection is a global burden that results in numerous hospital visits and deaths annually. The rise of multi-drug resistant bacteria has dramatically increased this burden. Therefore, there is a clinical need to detect and identify bacteria rapidly and accurately in their native state or a culture-free environment. Current diagnostic techniques lack speed and effectiveness in detecting bacteria that are culture-negative, as well as options for in vivo detection. The optical detection of bacteria offers the potential to overcome these obstacles by providing various platforms that can detect bacteria rapidly, with minimum sample preparation, and, in some cases, culture-free directly from patient fluids or even in vivo. These modalities include infrared, Raman, and fluorescence spectroscopy, along with optical coherence tomography, interference, polarization, and laser speckle. However, these techniques are not without their own set of limitations. This review summarizes the strengths and weaknesses of utilizing each of these optical tools for rapid bacteria detection and identification. [ABSTRACT FROM AUTHOR]

Rickettsia species are an important cause of emerging infectious diseases in people and animals, and rickettsiosis is one of the oldest known vector-borne diseases. Laboratory diagnosis of Rickettsia is complex and time-consuming. This study was aimed at developing two quantitative real-time PCRs targeting ompB and ompA genes for the detection, respectively, of Rickettsia spp. and R. conorii DNA. Primers were designed following an analysis of Rickettsia gene sequences. The assays were optimized using SYBR Green and TaqMan methods and tested for sensitivity and specificity. This study allowed the development of powerful diagnostic methods, able to detect and quantify Rickettsia spp. DNA and differentiate R. conorii species. [ABSTRACT FROM AUTHOR]

The ability to detect, identify and quantify bacteria is crucial in clinical diagnostics, environmental testing, food security settings and in microbiology research. Recently, the threat of multidrug-resistant bacterial pathogens pushed the global scientific community to develop fast, reliable, specific and affordable methods to detect bacterial species. The use of synthetically modified enzyme substrates is a convenient approach to detect bacteria in a specific, economic and rapid manner. The method is based on the use of specific enzyme substrates for a given bacterial marker enzyme, conjugated to a signalogenic moiety. Following enzymatic reaction, the signalophor is released from the synthetic substrate, generating a specific and measurable signal. Several types of signalophors have been described and are defined by the type of signal they generate, such as chromogenic, fluorogenic, luminogenic, electrogenic and redox. Signalophors are further subdivided into groups based on their solubility in water, which is key in defining their application on solid or liquid media for bacterial culturing. This comprehensive review describes synthetic enzyme substrates and their applications for bacterial detection, showing their mechanism of action and their synthetic routes. [ABSTRACT FROM AUTHOR]

In clinical culture media inoculated with patient samples, selective inhibition of commensal bacteria is essential for accurate diagnosis and effective treatment, as they can mask the presence of pathogenic bacteria. The alanine analogue, 1-aminoethyltetrazole was investigated as a potential alanine racemase inhibitor. For effective uptake and enhanced and selective antibacterial activity, a library of C-terminal 1-aminoethyltetrazole containing di- and oligopeptides were synthesized by solid phase peptide coupling techniques. The investigation of the antimicrobial activity of the synthesised compounds identified several clinically applicable selective inhibitors. These enabled differentiation between the closely related bacteria, Salmonella and Escherichia coli, which can be difficult to discriminate between in a clinical setting. In addition, differentiation between enterococci and other Gram-positive cocci was also seen. [ABSTRACT FROM AUTHOR]

The title compound, C(21)H(26)N(2)O(5), was unexpectedly obtained as a by-product in the reaction of ethyl acetoacetate, 4-acetamido-benzaldehyde and urea under microwave irradiation. The dihydro-pyridine ring assumes a flattened boat conformation. Inter-molecular N-H⋯O and weak C-H⋯O hydrogen bonding occurs in the crystal.

In the title compound, C(21)H(20)O(4), the central hepta-trienone unit is approximately planar, with a maximum atomic deviation of 0.1121 (11) Å; the two benzene rings are twisted with respect to the hepta-trienone mean plane by 2.73 (5) and 29.31 (4)°. The mol-ecule exists in the enol form and the hy-droxy group forms an intra-molecular hydrogen bond with the neighboring carbonyl group. Weak inter-molecular C-H⋯O hydrogen bonding is present in the crystal structure.

Background: Autism is a heterogeneous pervasive developmental disorder with a poorly defined aetiology and pathophysiology. There are indications that the incidence of the disease is rising but still no definitive diagnostic biochemical markers have been isolated. Here we have addressed the hypothesis that urinary levels of trans -indolyl-3-acryloylglycine (IAG) are abnormal in patients diagnosed with autism spectrum disorders (ASD) compared to age-matched controls., Material/methods: Urine samples were collected on an opportunistic basis and analysed for IAG concentration (normalised against creatinine content to account for changes in urinary volume) using reversed phase HPLC with UV detection., Results: Statistical analysis (Mann-Whitney tests) showed highly significant increases (p=0.0002) in the levels of urinary IAG in the ASD group (median 942 microV per mmol/L of creatinine [interquartile range 521-1729], n=22) compared to asymptomatic controls (331 [163-456], n=18). Detailed retrospective analysis showed that gender (boys 625 microV per mmol/L of creatinine [294-1133], n=29; girls 460 [282-1193], n=11: P=0.79) and age (control donor median 10 years [8-14], n=15; ASD median 9 years [7-11] n=22: P=0.54) were not significantly correlated with IAG levels in this non-blinded volunteer study., Conclusions: Our results strongly suggest that urinary titres of IAG may constitute an objective diagnostic indicator for ASD. Mechanisms for the involvement of IAG in ASD are discussed together with future strategies to address its specificity.