J. Appl. Cryst.の発刊に際して

Adequate initial configurations for molecular dynamics simulations consist of arrangements of molecules distributed in space in such a way to approximately represent the system's overall structure. In order that the simulations are not disrupted by large van der Waals repulsive interactions, atoms from different molecules must keep safe pairwise distances. Obtaining such a molecular arrangement can be considered a packing problem: Each type molecule must satisfy spatial constraints related to the geometry of the system, and the distance between atoms of different molecules must be greater than some specified tolerance. We have developed a code able to pack millions of atoms, grouped in arbitrarily complex molecules, inside a variety of three-dimensional regions. The regions may be intersections of spheres, ellipses, cylinders, planes, or boxes. The user must provide only the structure of one molecule of each type and the geometrical constraints that each type of molecule must satisfy. Building complex mixtures, interfaces, solvating biomolecules in water, other solvents, or mixtures of solvents, is straightforward. In addition, different atoms belonging to the same molecule may also be restricted to different spatial regions, in such a way that more ordered molecular arrangements can be built, as micelles, lipid double-layers, etc. The packing time for state-of-the-art molecular dynamics systems varies from a few seconds to a few minutes in a personal computer. The input files are simple and currently compatible with PDB, Tinker, Molden, or Moldy coordinate files. The package is distributed as free software and can be downloaded from http://www.ime.unicamp.br/~martinez/packmol/.

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PACKMOL: a package for building initial configurations for molecular dynamics simulations.

基礎講座 電気泳動(Electrophoresis)

It is important that the medical profession plays a significant role in critically evaluating the use of diagnostic procedures and therapies as they are introduced and tested in the detection, management, or prevention of disease states. Rigorous and expert analysis of the available data documenting absolute and relative benefits and risks of those procedures and therapies can produce helpful guidelines that improve the effectiveness of care, optimize patient outcomes, and favorably affect the overall cost of care by focusing resources on the most effective strategies.

The American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA) have jointly engaged in the production of such guidelines in the area of cardiovascular disease since 1980. The ACC/AHA Task Force on Practice Guidelines, whose charge is to develop, update, or revise practice guidelines for important cardiovascular diseases and procedures, directs this effort. The Task Force is pleased to have this guideline developed in conjunction with the European Society of Cardiology (ESC). Writing committees are charged with the task of performing an assessment of the evidence and acting as an independent group of authors to develop or update written recommendations for clinical practice.

Experts in the subject under consideration have been selected from all 3 organizations to examine subject-specific data and write guidelines. The process includes additional representatives from other medical practitioner and specialty groups when appropriate. Writing committees are specifically charged to perform a formal literature review, weigh the strength of evidence for or against a particular treatment or procedure, and include estimates of expected health outcomes where data exist. Patient-specific modifiers, comorbidities, and issues of patient preference that might influence the choice of particular tests or therapies are considered as well as frequency of follow-up and cost effectiveness. When available, information from studies on cost will be considered; however, review …

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ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death

The concept of metabolite profiling has been around for decades, but technical innovations are now enabling it to be carried out on a large scale with respect to the number of both metabolites measured and experiments carried out. Here we provide a detailed protocol for gas chromatography mass spectrometry (GC-MS)-based metabolite profiling that offers a good balance of sensitivity and reliability, being considerably more sensitive than NMR and more robust than liquid chromatography-linked mass spectrometry. We summarize all steps from collecting plant material and sample handling to derivatization procedures, instrumentation settings and evaluating the resultant chromatograms. We also define the contribution of GC-MS-based metabolite profiling to the fields of diagnostics, gene annotation and systems biology. Using the protocol described here facilitates routine determination of the relative levels of 300-500 analytes of polar and nonpolar extracts in approximately 400 experimental samples per week per machine.

Gas chromatography mass spectrometry–based metabolite profiling in plants

Neue Antibiotika: Den Vorsprung gegenüber resistenten Bakterien wahren

Capillary electropherosis (CE) has been proved to be an important alternative to high-performance liquid chromatography (HPLC) in pharmaceutical analysis. However, when it comes to the analysis of compounds, e.g. impurities or metabolites, of very different polarity and water solubility CE and the related techniques come to its limits. This is demonstrated for the antipsychotic drug quetiapine and its impurities. A nonaqueous capillary electrophoresis (NACE) method was developed using a background electrolyte (BGE) composed of ammonium acetate dissolved in a mixture of acetonitrile and methanol including acetic acid to protonate the substances. The NACE method gave an excellent separation of all components. Since the conductivity of the BGE used in the NACE method is quite low and problems with current occurred, an additional aqueous capillary zone electrophoresis (CZE) method was developed for quetiapine and the two water soluble derivatives, using phosphate buffer as BGE. The method was validated with regard to repeatability and limit of detection.

Possibilities and limitations of capillary electropherosis in pharmaceutical analysis.

Opening NADPH oxidase inhibitors for in vivo translation.

2,4-Diaryl substituted 3,7-diazabicyclo[3.3.1]nonan-9-one-1,5-dicarboxylates are attracting interest as opioid-like analgesics. Since the stereochemistry is of great importance for a high affinity to the κ-receptor, the influence of substituents on the skeleton has to be considered. As a part of a greater project the influence of substituents in position N3 of the 3,7-diazabicyclo[3.3.1]nonanone on the conformation and configuration of the ring system was studied here. Whereas the variations of the substitution pattern of the arene rings revealed the cis substituted isomers in a chair–chair conformation mostly to be the thermodynamically stable form, alkyl substituents at N3 of increasing size induce the trans configuration of the phenyl rings often combined with a boat–chair conformation. The configuration was confirmed by X-ray analysis. Semiempirical calculations were performed to elucidate the thermodynamic stability of the isomers.
However, some substituents having unsaturated bonds, such as propargyl (prop-2-enyl) and phenylethyl residues, seem to stabilise the cis configuration of the arene rings in a chair–chair conformation.

Stereochemical behaviour of κ-agonistic 2,4-dipyridin-2-yl-3,7-diazabicyclo[3.3.1]nonanones—influence of the substituent in position N3

For assurance of the quality of active pharmaceutical ingredients (APIs) used for manufacturing medicines, the analytical requirements of the European Pharmacopoeia serve as a guideline and have a binding character. Within a particular timeframe, an API is considered to comply with predefined specifications. If applicable, it can be used for the manufacturing of a finished pharmaceutical product. The objective of the study presented here was to assess the long-term stability of 50 drug substances with an age of 20-30 years or even older in some cases. The substances are part of a collection of old pharmaceuticals at the Institute for Pharmacy in Wurzburg, Germany, and represent commonly used drug classes containing β-blockers, β-sympathomimetic drugs, anticholinergics, anti-infectives, non-steroidal anti-inflammatory drugs, antipsychotics, antihistaminic drugs, and one antiarrhythmic drug. The content and the degradation profile of the items were determined by means of potentiometric titration and liquid chromatography techniques based on pharmacopoeial approaches for impurity profiling covering all process and degradation related substances. The results of the study show that 44 out of 49 tested substances still complied with specifications of the current pharmacopoeias. For metipranolol, which is not monographed in any pharmacopoeia, a small degradation by hydrolysis was observed. In one lot of ampicillin sodium, atenolol, atropine, penbutolol, and salbutamol, at least one impurity did not meet the acceptance criteria, respectively. Some impurities were not related to degradation. However, a surprisingly high chemical stability of the old drug substances was revealed after more than two decades of storage.

Ulrike Holzgrabe

Papers

Neue Antibiotika: Den Vorsprung gegenüber resistenten Bakterien wahren

Possibilities and limitations of capillary electropherosis in pharmaceutical analysis.

Opening NADPH oxidase inhibitors for in vivo translation.

Stereochemical behaviour of κ-agonistic 2,4-dipyridin-2-yl-3,7-diazabicyclo[3.3.1]nonanones—influence of the substituent in position N3

A long-time stability study of 50 drug substances representing common drug classes of pharmaceutical use.