Effect of the moisture content in aerosol on the spray performance of Stmerin D HFA preparations

Stmerin D, a pressurized metered dose inhaler (MDI) for treatment of asthma, contains CFCs (chlorofluorocarbons) as a propellant. For the CFC replacement study, two formulations were prepared using hydrofluoroalkanes (HFA-134a and HFA-227) and the effect of storage on the spray performance was investigated under accelerated stress conditions. Drug stability, moisture content and spray performances such as the emitted dose uniformity and aerodynamic particle size distribution were evaluated. Drug content did not change after 3 months storage at 40 degrees C/75% RH. However, the emitted dose uniformity varied and the respirable fraction (RF) was reduced remarkably. While stored at 40 degrees C/ambient for 3 months, no change was observed in either drug content or spray performances. This study clarified that the moisture content in the canister played an important role on the spray performance, and it changed not only the emitted dose uniformity but also the particle size distribution. Consequently, in order to improve the stability of the spray performance of aerosol prepared with HFAs, moisture permeation into the canister must be controlled.     

TEMPO-substituted polyacrylamide for an aqueous electrolyte-typed and organic-based rechargeable device

A hydrophilic radical polymer, poly(2,2,6,6-teteramethylpiperidinyloxyl-4-yl acrylamide) (PTAm), was synthesized via oxidation of the corresponding precursor polymer, poly(2,2,6,6-teteramethylpiperidine-4-yl acrylamide). Electrochemical properties of the PTAm layer were characterized in three aqueous electrolytes of sodium chloride (NaCl), sodium tetrafluoroborate (NaBF4), and sodium hexafluorophosphate (NaPF6) to optimize its activity as an organic cathode. The counter anion species significantly affected the capacity and the cycle performance of the PTAm layer. The PTAm layer in the presence of BF4? displayed quantitative redox capacity beyond 1 μm layer thickness and maintained the discharging capacity of 110 mAh g-1 (97% vs. the calculated capacity) even after 1000 cycle charging/discharging, which could be ascribed to its appropriate affinity to the aqueous electrolyte without any dissolution into the electrolyte. A totally organic-based rechargeable cell was fabricated using PTAm and poly(N-4,4’-bipyridinium-N-decamethylene dibromide) as the cathode and the anode, respectively, and the aqueous electrolyte of NaBF4. The cell gave a plateau voltage at 1.2 V both on charging and discharging and an excellent charging/discharging cyclability of >2000 with high coulombic efficiency of >95%.     

Porphyrin Network Polymers Prepared via a Click Reaction and Facilitated Oxygen Permeation Through Their Membranes

Network polymers of cobaltporphyrin derivatives are prepared by a facile click reaction via the Michael addition of acetoacetate‐substituted tetraphenyl cobaltporphyrin and tri‐ or tetra‐acrylates. The conversion is saturated for 1 h in the presence of a catalyst, which almost reaches the same gelation point of the formed network polymers. Deeply and homogeneously red‐colored membranes with a sub‐micrometer thickness are yielded on a porous supporting membrane. They are still tough even with a very high content of the rigid porphyrin residue. The oxygen permeability is high, at 10–100 Barrer, and the oxygen/nitrogen permselectivity (P_O2/P_N2) is significantly enhanced with the porphyrin content reaching 30, for the membranes with ca. 70 wt% porphyrin content.

     

Simple water analysis of golf link pesticides by means of batch-wise adsorption and supercritical fluid extraction

Here, a simple new method is proposed to evaluate water for the presence of pesticides. Specifically, pesticides for golf link maintenance were used as the targets for this investigation. Water samples containing the pesticides were mixed with particulate adsorbent, after which the pesticides were extracted from the adsorbents using supercritical fluid carbon dioxide and then analyzed by gas chromatography-mass spectrometry. The recoveries of pesticides were examined with several types of adsorbents and found to be related to their octanol/water partition coefficients (K_ow) for most of the adsorbents. Good recoveries were obtained when the water samples were mixed with octadecylsilane (ODS) and stylene-divinylbenzene copolymer (XAD) resins for 15 and 30 min, respectively. In the supercritical fluid extraction, extraction pressure affected the efficiency of extraction from XAD while a little effect on extraction from ODS, probably due to the internal structure of the adsorbents. The limit of detection ranged from 0.002 to 2.3 μg L⁻¹ and the method is suitable for the measurement of golf link pesticides in μg L⁻¹ order to 100 μg L⁻¹. The procedure of the proposed method was simpler than the conventional solid-phase extraction method. Finally, the method presented here was used to identify pesticides present in actual wastewater from golf links.     

Synthesis of 2-(3,5-dichloro-2-pyridylazo)-5-dimethylaminophenol and its application to the spectrophotometric determination of cobalt

2-(3,5-Dichloro-2-pyridylazo)-5-dimethylaminophenol (3,5-diCl-DMPAP) has been synthesized and its analytical application investigated. It reacts with cobalt in aqueous solution at pH 2.2-6.0 and room temperature to form a water-soluble ML(2) complex with absorption maximum at 590 nm, and molar absorptivity 8.4 x 10(4) l.mole(-1).cm(-1). Interference from other transition metals can be eliminated by their solvent extraction with 8-hydroxyquinoline. The method has been successfully applied to determination of cobalt in mild steels.     

Biodegradable and Electroactive TEMPO‐Substituted Acrylamide/Lactide Copolymers

Copolymers composed of PLA and PTAm were prepared by a macromonomer approach. The PLA bearing vinyl group at chain end was copolymerized with 2,2,6,6‐tetrametylpiperidine‐4‐ylacrylamide. The resulted copolymers were oxidized by a peroxide to give PTAm‐g‐PLA. The structures of the copolymers were confirmed by NMR and FTIR spectroscopy. The comparison of ¹H NMR results and SQUID measurements demonstrated that the oxidation of the PTAm fragment proceeded almost to completion. An MTT assay, cell adhesion and spreading evaluation showed that the copolymers exhibited improved cytocompatibility as compared to the PTAm homopolymer due to the introduction of the biocompatible PLA moiety.

     

Synthesis of amphiphilic block copolymers bearing stable nitroxyl radicals

We present here the synthesis of two kinds of amphiphilic block copolymers, a diblock copolymer MPEG‐b‐PTAm and a triblock copolymer MPEG‐b‐PLA‐b‐PTAm, which can self‐assemble into micelles with nitroxyl radicals‐containing PTAm segment in the core. The structure of the block copolymers was characterized by ¹H NMR and GPC. Dynamic laser light scattering and transmission electron microscopy were used to study the micellar behavior of the two block copolymers in aqueous solution. The micelles carrying nitroxyl radicals in the core can generate electron paramagnetic resonance, which is stable for a period of time up to 8 min even in the presence of reducing reagent such as ascorbic acid. The enhanced stability against the reducing agent was ascribed to the inaccessibility of the nitroxyl radical core placed in the interior of the micelles. Combined with the biocompatibility, these micelles were promising to be used as the EPR probes for bioimaging in vivo. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010