Near‐IR‐Triggered,Remote‐Controlled Release of Metal Ions: A Novel Strategy for Caged Ions

A ligand incorporating a dithioethenyl moiety is cleaved into fragments which have a lower metal‐ion affinity upon irradiation with low‐energy red/near‐IR light. The cleavage is a result of singlet oxygen generation which occurs on excitation of the photosensitizer modules. The method has many tunable factors that could make it a satisfactory caging strategy for metal ions.     

Preconcentration of metal ions using microbacteria

This review (160 refs). covers the current state of the art of microbacteria-based sorbents for preconcentration of metal ions at trace levels. We highlight advantages and major challenges of the techniques and discuss future perspectives of both batch and column-based methods. Particular attention is paid to the preconcentration of metal ions using resin-immobilized microbacteria for solid phase extractions. We also discuss detection methods including UV–vis spectrophotometry, FAAS, ICP-OES and ICP-MS. Analytical figures of merit are compared, and examples are given for the application to a variety of samples including food, beverages, alloys, water, soil, and geological samples.

Rapid and Efficient Microwave‐Assisted Synthesis of Some New Triazol‐3‐one Derivatives

A growing body of literature has shown the effectiveness of using microwaves in chemical reactions. The aim of this study is to demonstrate a rapid and highly efficient synthesis of some new triazol‐3‐ones via microwave heating using a monomode microwave. Compared with the thermal process, the microwave heating induces a dramatic reduction of the reaction time and improvement of the yields. In this study, rapid N‐benzylation and N‐acetylation of triazol‐3‐ones were achieved by microwave irradiation method for the first time. The newly synthesized compounds showed moderate antimicrobial activity against the standard bacterial and fungal organisms tested.     

Surface molecularly imprinted polydopamine films for recognition of immunoglobulin G

We have prepared a surface imprinted polymer (SIP) film for label-free recognition of immunoglobulin G (IgG). The IgG-SIPs were obtained by covalent immobilization of IgG via a cleavable covalent bond and a suitable spacer unit to a gold electrode, followed by electrodepostion of a nm-thin film of polydopamine (PDA). The IgG was then removed by destruction of the cleavable bond so that complementary binding sites were created on the surface of the film. IgG-SIPs with various thicknesses of the PDA films were compared with respect to their affinity to IgG using a quartz crystal microbalance combined with flow injection analysis. The films were also characterized by cyclic voltammetry and scanning electron microscopy. The IgG-SIPs with a film thickness of around 17 nm showed the most pronounced imprinting effect (IF 1.66) and a binding constant of 296 nM.

Determination of Dimenhydrinate Nasal Delivery System in the Blood by RP-LC

Dimenhydrinate (DM) is used therapeutically for the prevention of motion sickness associated with nausea and vomiting. The aim of this investigation is the development of a new, rapid, sensitive, simple and fully validated RP-LC procedure for the suitable assay of DM in pharmaceutical formulation applied in blood samples. The method was validated before the amount determination studies in order to confirm linearity, precision, accuracy, selectivity, determination and quantification limit and consistency. High determination coefficient (r ²  = 0.998) of the standard curve drawn in the linearity studies showed that the line equation can be used in the quantification of the DM. Literature was reviewed for the methods based on diphenhydramine (DIP), its metabolite dimenhydrinate, in the in vivo determination of dimenhydrinate amount. The most appropriate method to be used in LC was decided to be the method applied by benefitting from the fluorescence characteristic of DIP. Maximum excitation and emission wavelengths in the developed method were scanned using multiple wavelengths and, maximum excitation and emission wavelengths were found to be 215 and 300 nm, respectively. In the validation study used to prove validity of the method, determination coefficient of the developed standard curve was calculated as 0.998 (RSD %), and line equation was concluded to be appropriate for use in amount determination studies. BBS % (1.06, 1.84 %) values obtained as “<2 %” in the intra-day and inter-day precision studies proved the precision of the method. Selectivity study revealed that other materials used in the formulation did not exhibit absorbance in the same wavelengths. Detection and quantification limit were found as 1 and 5 ng mL^?1, respectively. The determination of DM plasma concentrations using the proposed and fully validated LC assay has allowed us to characterize DMPK in the sheep, as well as determine DM relative bioavailability.     

Simultaneous Determination of Clobetasol Propionate and Calcipotriol in a Novel Fixed Dose Emulgel Formulation by LC-UV

A new, rapid, selective, cheap and simple RP-LC method has been developed and validated for the simultaneous determination of clobetasol propionate and calcipotriol mixtures in bulk drugs (raw materials) and in a novel-fixed dose emulgel formulation. Separation was carried out using a NovaPak C18 column with methanol:water (74:26 v/v) as mobile phase for isocratic elution at a flow rate of 1.0 mL min^?1. The column temperature was set at 25 °C. Calibration curves were established ranging between 0.5 and 20 μg mL^?1 and 0.5 and 10 μg mL^?1 for clobetasol propionate and calcipotriol, respectively. Limit of detection and limit of quantification values of the method was found as 0.16 and 0.48 μg mL^?1 for clobetasol propionate and 0.10 and 0.30 μg mL^?1 for calcipotriol, respectively. The method was validated in accordance with ICH guidelines and obtained results proved that the proposed method was precise, accurate, selective and sensitive for the simultaneous analysis of clobetasol propionate and calcipotriol. The proposed method can be easily applied for the simultaneous determination of clobetasol propionate and calcipotriol in prepared emulgel formulations. The obtained validation results showed that the RP-LC method is suitable for routine quantification of clobetasol propionate and calcipotriol in emulgel formulations with high precision and accuracy.     

Reactions of Electron-Rich Olefins with Proton-Active Compounds

Abstract: From the reaction of electron-rich olefins, bis(1,3-dimethylbenzimidazolidine-2-ylidene), I, or bis(3-methylbenzothiazolidine-2-ylidene), II with proton active compounds, such as dimethyl phosphite, diethyl phosphite, acetonitrile and benzaldehyde were obtained 2-substituted benzimidazole or benzothiazole derivatives. The compounds synthesized were identified by ¹H, ¹³ C, ³¹P-NMR, mass, FT-IR spectroscopic techniques and micro analysis.     

Solvent-Free Synthesis of Nitrilotriacetamide and Diketopiperazines from Nitrilotriacetic Acid under Microwave Irradiation and Their Antimicrobial Activity

Efficient synthesis of dioxopiperazines‐diketopiperzines (DKPs)‐ and amide from nitrilotriacetic acid (NTA) using microwave irradiation and classical heating were described. All compounds were characterized using ¹H NMR, ¹³C NMR and elemental analysis. Antimicrobial effects of these compounds are also investigated. All tested compounds showed moderate antimicrobial activity.     

Preparation of Some Thiazolyl Hydrazone Derivatives and Evaluation of Their Antibacterial Activities

The increasing clinical importance of drug-resistant fungal and bacterial pathogens has provided additional urgency to microbiological research and to the development of new antibacterial compounds. For this purpose, new tert-butyl [1-aryl/alkyl-2[(4-aryl-2-thiazolyl)hydrazono]ethyl]carbamate derivatives were synthesized and evaluated for antibacterial activity. The reaction of Boc-L-phenylalaninal, Boc-D-phenylalaninal, Boc-L-leucinal, and Boc-L-tryptophanal with thiosemicarbazide yielded the thiosemicarbazones, which furnished the title compounds on reaction with phenacyl bromides. The new compounds were screened for antibacterial activity. The results from the bioassay tests show that some of the compounds have notable activity against Gram-positive bacteria.     

The Synthesis and Characterization of Aryloxy-Linear Phosphazenes

The reactions of N-dichlorophosphoryl-P-trichloromonophosphazene with sodium o-methylphenoxide, sodium p-methylphenoxide, sodium f -naphthalenoxide, monosodium 4-(2-pyridylazo)resorcinol, and sodium 1-nitroso-2-naphthaleneoxide have been investigated. Experimental studies were carried out in argon atmosphere. The sodium aryloxides were prepared from naphthalene or phenol derivatives and metallic sodium. The phosphazene and phenolate or naphthaleneoxide were reacted at 0°;C and then refluxed. After the reaction products were separated by using column chromatography, the structures of the compounds were defined by elemental analysis, IR, 1 H, 13 C, 31 P NMR, and mass spectroscopy. Tetra- and pentasubstituted monophosphazenes were obtained from sodium o-methylphenoxide. Pentasubstituted derivatives also were obtained from sodium p-methylphenoxide and sodium f -naphthaleneoxide. Phosphazene or any phosphorus compound could not be isolated from the reaction of phosphazene with monosodium 4-(2-pyridylazo)resorcinol and sodium 1-nitroso-2-naphthaleneoxide.