Microwave-Assisted Synthesis, Structural Characterization and Assessment of the Antibacterial Activity of Some New Aminopyridine, Pyrrolidine, Piperidine and Morpholine Acetamides.

A series of new acetamide derivatives 22-28 of primary and secondary amines and para-toluene sulphinate sodium salt have been synthesized under microwave irradiation and assessed in vitro for their antibacterial activity against one Gram-positive and two Gram-negative bacterial species such as S. pyogenes, E. coli, and P. mirabilis using the Mueller-Hinton Agar diffusion (well diffusion) method. The synthesized compounds with significant differences in inhibition diameters and MICs were compared with those of amoxicillin, ampicillin, cephalothin, azithromycin and doxycycline. All of the evaluated acetamide derivatives were used with varying inhibition concentrations of 6.25, 12.5, 37.5, 62.5, 87.5, 112.5 and 125 µg/mL. The results show that the most important antibacterial properties were displayed by the synthetic compounds 22 and 24, both of bear a para-chlorophenyl moiety incorporated into the 2-position moiety of acetamide 1. The molecular structures of the new compounds were determined using the FT-IR and 1H-NMR techniques.

Influence of photo-initiators in the preparation of methacrylate monoliths into poly(ethylene-co-tetrafluoroethylene) tubing for microbore HPLC.

In this study, poly(butyl methacrylate-co-ethyleneglycol dimethacrylate) polymeric monoliths were in situ developed within 0.75 mm i.d. poly(ethylene-co-tetrafluoroethylene) (ETFE) tubing by UV polymerization via three different free-radical initiators (α,α'-azobisisobutyronitrile (AIBN), 2,2-dimethoxy-2-phenylacetophenone (DMPA) and 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (MTMPP). The influence of the nature of each photo-initiator and irradiation time on the morphological features of the polymer was investigated by scanning electron microscopy, and the chromatographic properties of the resulting microbore columns were evaluated using alkyl benzenes as test substances. The beds photo-initiated with MTMPP gave the best performance (minimum plate heights of 38 µm for alkyl benzenes) and exhibited a satisfactory reproducibility in the chromatographic parameters (RSD < 11%). These monolithic columns were also successfully applied to the separation of phenylurea herbicides, proteins and a tryptic digest of ß-casein.

A photocaged fluorescent probe for imaging hypochlorous acid in lysosomes.

By combining the advantages of the photocaging technology and traditional analyte-responsive fluorescent probes, we designed and synthesized the first photocaged lysosomal-targeted fluorescent HOCl probe (PL-HA). The new caged PL-HA probe was capable of remote light-controlled recognition of HOCl in lysosomes.

A photostable fluorescent probe for long-time imagining of lysosome in cell and nematode.

Lysosome fluorescent imaging has been widely used in the field of biological staining and diagnostics, which plays a key role in understanding intracellular metabolism and various physiological processes. However, for most currently used small-molecule lysotrackers, the photostability is often unsatisfactory when used for long-term and real-time visualization of lysosomal dynamics. Herein, we reported a new lysosome-targetable photostable fluorescent probe (i.e. MPL-NPA), and results showed that MPL-NAP possesses superior photostability, appreciable tolerance to pH change, low cytotoxicity and high lysosome targeting ability. These findings confirm that MPL-NAP is a well-suited imaging agent for targeting lysosome and enables long-term and real-time monitor of lysosome morphological changes under physiological processes.

Tracking mitochondrial pH fluctuation during cell apoptosis with two-photon phosphorescent iridium(iii) complexes.

Two iridium(iii) complexes with ligands containing morpholine groups were used to track mitochondrial pH fluctuation during cell apoptosis as their emissive intensities linearly increased with increase in pH values.

UV-curable gel formulations: Potential drug carriers for the topical treatment of nail diseases.

Nail diseases are common, cause significant distress and treatments are far from successful. Our aim was to investigate the potential of UV-curable gels - currently used as cosmetics - as topical drug carriers for their treatment. These formulations have a long residence on the nail, which is expected to increase patient compliance and the success of topical therapy. The gels are composed of the diurethane dimethacrylate, ethyl methacrylate, 2-hydroxy-2-methylpropiophenone, an antifungal drug (amorolfine HCl or terbinafine HCl) and an organic liquid (ethanol or NMP) as drug solvent. Following its application to a substrate and exposure to a UVA lamp for 2 min, the gel polymerises and forms a smooth, glossy and amorphous film, with negligible levels of residual monomers. No drug-polymer interactions were found and drug loading did not affect the film's properties, such as thickness, crystallinity and transition temperatures. In contrast, the organic solvent did influence the film's properties; NMP-containing films had lower glass transition temperatures, adhesion and water resistance than ethanol-based ones. Water-resistance being a desired property, ethanol-based formulations were investigated further for stability, drug release and ungual permeation. The films were stable under accelerated stability testing conditions. Compared to terbinafine, amorolfine was released to a greater extent, had a higher ungual flux, but a lower concentration in the nailplate. However, both drugs were present at considerably high levels in the nail when their MICs are taken into account. We thus conclude that UV-curable gels are promising candidates as topical nail medicines.

Compositional design and optimization of dentin adhesive with neutralization capability.

OBJECTIVES: The objective of this work was to investigate the polymerization behavior, neutralization capability, and mechanical properties of dentin adhesive formulations with the addition of the tertiary amine co-monomer, 2-N-morpholinoethyl methacrylate (MEMA). METHODS: A co-monomer mixture based on HEMA/BisGMA (45/55, w/w) was used as a control adhesive. Compared with the control formulation, the MEMA-containing adhesive formulations were characterized comprehensively with regard to water miscibility of liquid resin, water sorption and solubility of cured polymer, real-time photopolymerization kinetics, dynamic mechanical analysis (DMA), and modulated differential scanning calorimetry (MDSC). The neutralization capacity was characterized by monitoring the pH shift of 1mM lactic acid (LA) solution, in which the adhesive polymers were soaked. RESULTS: With increasing MEMA concentrations, experimental copolymers showed higher water sorption, lower glass transition temperature and lower crosslinking density compared to the control. The pH values of LA solution gradually increased from 3.5 to about 6.0-6.5 after 90 days. With the increase in crosslinking density of the copolymers, the neutralization rate was depressed. The optimal MEMA concentration was between 20 and 40 wt%. CONCLUSIONS: As compared to the control, the results indicated that the MEMA-functionalized copolymer showed neutralization capability. The crosslinking density of the copolymer networks influenced the neutralization rate.

Solution stability of ciclosidomine.

The stability of N-cyclohexanecarbonyl-3-(4-morpholino)-sydnone imine hydrochloride (ciclosidomine) in solution was studied as a function of pH, temperature, ionic strength, and buffer species. The rate of hydrolysis in the absence of light was found to be apparent first order in drug and general acid- and base-catalyzed reactions. The pH rate profile at an ionic strength of 0.1 M at 60 degrees C had a minimum value near pH 6. Change in ionic strength in the range of 0.05 to 0.2 M did not affect the rate of degradation at pH 7 (carbonate buffer) or pH 2 (phosphate buffer) at 60 degrees C. Similar degradation rates were noticed in air or nitrogen in the dark at pH 3, 5, and 6. However, degradation in light was very rapid in either case at pH 3, 5, and 6, and, therefore, the protection of solutions from light was required during all studies. The time for 10% loss of drug in solution at pH 6 in dilute phosphate or citrate buffer at an ionic strength of 0.154 M was projected to be 9 months at 20 degrees C and 2.6 months at 30 degrees C.