Dipodal pyridylthiazole amine ligands L and L both form different metallo-supramolecular self-assemblies with Zn and Cu and these are shown to be toxic and selective towards cancer cell lines in vitro. Furthermore, potency and selectivity are highly dependent upon the metal ions, ligand system and bound anion, with significant changes in chemosensitivity and selectivity dependent upon which species are employed. Importantly, significant anti-tumor activity was observed in ovo at doses that are non-toxic.
View Article and Find Full Text PDFE-liquids typically contain nicotine and flavourings in a matrix of propylene glycol (PG) and vegetable glycerine (VG). Some nicotine-free e-liquids are flavouring only in the aerosol carrier with the option for users to add their own nicotine. It is only the nicotine that is monitored in terms of level, as specified by the manufacturers.
View Article and Find Full Text PDFElectronic cigarettes are a relatively new alternative to cigarettes, which have been marketed as being safer for users than conventional cigarettes. However, they may still result in inhalation of potentially toxic or carcinogenic substances, including metals produced by the heating element. This study looked at the levels of trace metals being produced by different atomizers used in e-cigarettes using a sample introduction technique based on the collection of aerosols produced by e-cigarettes in nitric acid, using glass midget impingers.
View Article and Find Full Text PDFThere is a requirement for reliable real-time analytical tools for reaction monitoring to optimise chemical syntheses. We have developed a new technique which combines thermal analysis, digital microscopy and chemical identification using ambient ionisation mass spectrometry. We term this hot-stage microscopy-Direct Analysis in Real-Time mass spectrometry (HDM).
View Article and Find Full Text PDFThe ligands L and L form trinuclear self-assembled complexes with Cu (i.e. [(L ) Cu ] or [(L ) Cu ] ) both of which act as a host to a variety of anions.
View Article and Find Full Text PDFRationale: Polymers are ubiquitous, and characterisation of their chemical, thermal and mechanical properties is important in many applications. Hot-stage microscopy Direct Analysis in Real Time mass spectrometry (HDM) is a new technique which combines optical measurements with the benefits of ambient ionisation mass spectrometry. Physical and chemical information can be obtained as a function of sample temperature, in real time.
View Article and Find Full Text PDFThe extent of human intestinal absorption (HIA) for a drug is considered to be an important pharmacokinetic parameter which must be determined for orally administered drugs. Traditional experimental methods relied upon animal testing and are renowned for being time consuming and expensive as well as being ethically unfavourable. As a result, the development of alternative methods to evaluate a drug's pharmacokinetics is crucial.
View Article and Find Full Text PDFThe unique character of bile salts to self-assemble into hydrogels in the presence of halide salts was exploited in this work to facilitate the prediction of human intestinal absorption (%HIA) for a set of 25 compounds. This was achieved by firstly incorporating each compound separately within the process of gel formation to create a series of gel-drug membranes. Scanning electron microscopy analysis of the freeze-dried samples of the blank bile salt hydrogels and drug-loaded bile salt hydrogels indicated a unique microstructure made of a network of intertwined fibrils.
View Article and Find Full Text PDFMicellar liquid chromatography is a popular method used in the determination of a compound's lipophilicity. This study describes the use of the obtained micelle-water partition coefficient (log P ) by such a method in the prediction of human intestinal absorption (HIA). As a result of the close resemblance of the novel composition of the micellar mobile phase to that of physiological intestinal fluid, prediction was deemed to be highly successful.
View Article and Find Full Text PDFThree mesoporous silica excipients (Syloid® silicas AL-1 FP, XDP 3050 and XDP 3150) were formulated with a model drug known for its poor aqueous solubility, namely phenylbutazone, in an attempt to enhance the extent and rate of drug dissolution. Although other forms of mesoporous silica have been investigated in previous studies, the effect of inclusion with these specific Syloid® silica based excipients and more interestingly, with phenylbutazone, is unknown. This work reports a significant enhancement for both the extent and rate of drug release for all three forms of Syloid® silica at a 1:1 drug:silica ratio over a period of 30 min.
View Article and Find Full Text PDFThis paper describes a new analytical instrument that combines a precisely temperature-controlled hot-stage with digital microscopy and Direct Analysis in Real Time-mass spectrometry (DART-MS) detection. The novelty of the instrument lies in its ability to monitor processes as a function of temperature through the simultaneous recording of images, quantitative color changes, and mass spectra. The capability of the instrument was demonstrated through successful application to four very varied systems including profiling an organic reaction, decomposition of silicone polymers, and the desorption of rhodamine B from an alumina surface.
View Article and Find Full Text PDFHuman intestinal absorption (HIA) will dictate biopharmaceutical performance through its influence on absorption, distribution, metabolism, and elimination and can vary significantly depending upon the nature of the compound under consideration. In this study, an in vitro assay method is proposed for the prediction of HIA through the measurement of drug solubility in an aqueous phase containing micellar bile salt, namely sodium deoxycholate. A series of twenty compounds, displaying a range of physicochemical properties and known HIA values, were analyzed using UV spectroscopy to determine a solubilization ratio for each compound.
View Article and Find Full Text PDFUnderstanding intestinal absorption for pharmaceutical compounds is vital to estimate the bioavailability and therefore the in vivo potential of a drug. This study considers the application of micellar liquid chromatography (MLC) to predict passive intestinal absorption with a selection of model compounds. MLC is already known to aid prediction of absorption using simple surfactant systems; however, with this study the focus was on the presence of a more complex, bile salt surfactant, as would be encountered in the in vivo environment.
View Article and Find Full Text PDFA survey of the effect of temperature, transmission module material and analysis time on ion intensities in transmission mode direct analysis in real time mass spectrometry is presented. Ion intensity profiles obtained for two related compounds are similar when analysed separately but are very different when analysed as a mixture.
View Article and Find Full Text PDFAAPS PharmSciTech
December 2011
The first successful development of controlled microwave processing for pharmaceutical formulations is presented and illustrated with a model drug (ibuprofen) and two excipients (stearic acid and polyvinylpyrrolidone). The necessary fine temperature control for formulation with microwave energy has been achieved using a uniquely modified microwave oven with direct temperature measurement and pulse-width modulation power control. In addition to comparing microwave and conventional heating, the effect of the presence of liquid (water) in aiding the mixing of the drug and excipient during formulation was also investigated.
View Article and Find Full Text PDFThis article describes a system to investigate the parameters for the remediation of organic vapors using microwave-induced plasma on fluidized carbon granules. The system is based on a single mode microwave apparatus with a variable power (2.45 GHz) generator.
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