Metabolism of a synthetic compared with a natural therapeutic pulmonary surfactant in adult mice

Secreted pulmonary surfactant phosphatidylcholine (PC) has a complex intra-alveolar metabolism that involves uptake and recycling by alveolar type II epithelial cells, catabolism by alveolar macrophages, and loss up the bronchial tree. We compared the in vivo metabolism of animal-derived poractant alfa (Curosurf) and a synthetic surfactant (CHF5633) in adult male C57BL/6 mice. The mice were dosed intranasally with either surfactant (80 mg/kg body weight) containing universally 13C-labeled dipalmitoyl PC (DPPC) as a tracer. The loss of [U13C]DPPC from bronchoalveolar lavage and lung parenchyma, together with the incorporation of 13C-hydrolysis fragments into new PC molecular species, was monitored by electrospray ionization tandem mass spectrometry. The catabolism of CHF5633 was considerably delayed compared with poractant alfa, the hydrolysis products of which were cleared more rapidly. There was no selective resynthesis of DPPC and, strikingly, acyl remodeling resulted in preferential synthesis of polyunsaturated PC species. In conclusion, both surfactants were metabolized by similar pathways, but the slower catabolism of CHF5633 resulted in longer residence time in the airways and enhanced recycling of its hydrolysis products into new PC species

fac-Tris(pyridine-2-carboxyl­ato-κ2 N,O)cobalt(III)

In the title compound, [Co(C6H4NO2)3], the CoIII ion lies on a threefold rotation axis and is in a distorted octa­hedral environment defined by three N and three O donor atoms from three fac-disposed pyridine-2-carboxyl­ate ligands. The ligands are coordinated in a chelate fashion, forming three five-membered rings. In the crystal, translationally related complex molecules are organized into columns along [001] via C—H⋯O hydrogen bonds

Calix[4]arenes with Perfluorinated Alcoholic Functions at the Upper Rim. A New Class of Neutral Anion Receptors

Two or four perfluorinated alcoholic functions were successfully introduced at the upper rim of calix[4]arenes, affording a new type of neutral receptor for anion recognition; preliminary binding studies indicate that the difunctionalized receptors 3a and 3b are selective for Y-shaped carboxylate ions over spherical anions which are, on the contrary, more efficiently bound by the tetraalcohol 6

New Tetrafunctionalized Cone Calix[4]arenes as Neutral Hosts for Anion Recognition

The synthesis and anion binding properties of several new cone calix[4]arenes having different flexibility and tetrafunctionalized at the upper rim with various type of hydrogen bonding donor groups such as thioureas (1-3), trifluoroacetamides (4, 5) and perfluorinated alcohols (6) are reported. The results obtained show that thiourea receptors are the most effective in the complexation of all anions and that the rigid cone compound 2 is more efficient than the mobile cone analog 1 in the binding of spherical anions, whereas the reverse is true for the complexation of tetrahedral H2PO4- anion

Synthesis and Properties of New Calixarene-based Ditopic Reeptors for the Simultaneous Complexation of Cations and Carboxylate Anions

Calix[4]arene tetramide mono(thio)urea derivatives 5a,b and 9 are table to solubilize solid sodium salts of different anions in CDCl3 thanks to their ability to complex simultaneously the cation at the lower rim and the anion at the upper rim. Therefore they behave as ditopic receptors. Binding studies in [H-2(6)]DMSO performed only on the thiourea derivatives allowed us to establish that these receptors complex carboxylates better than spherical anions and that receptor 9 having the thiourea group directly connected to the aromatic nucleus is more efficient than 5a, which has a CH2 spacer between the two units; in the latter case good selectivity for the acetate anion is observed. Complexation of sodium ion by the amide groups at the lower rim causes an increase in the anion binding properties of receptor 9 and has little effect on receptor 5a. This is explained by the effects of the cation encapsulation on the hydrogen bonding ability of the thiourea units in the two receptors

On the detailed mechanisms of collision-induced dissociation experiments performed by electrospray ion trap

The product ion spectra obtained by electrospray ionization (ESI) ion trap instruments exhibit a higher number of fragment ions than those achieved by other ion-trap-based systems, indicating the presence of more effective energy deposition mechanisms. This behavior can be attributed to several different reasons, among which different initial internal energy of the precursor ions, pre-activation due to collisions taking place outside the trap, different target gas mixtures inside the trap, and different ion trap geometry were considered. Data obtained from experiments using a triple quadrupole instrument, CI-ion trap, and ESI-ion trap have been compared. The results so achieved seem to indicate that the presence inside the trap of neutral molecules of the solvent employed for the ESI process have a relevant role, promoting high energy deposition in the colliding ions

Strontium Complexes of calixarenes amides in the solid state: structural dependence on the ligand size and on the counter ion

For the first time, crystal structures of three strontium complexes of calixarene amides have been determined. A p-tert-butylcalix[6]arene hexaamide forms a 1 : 1 complex with Sr(Pic)(2) (Pic = picrate), whereas p-tert-butylcalix[8]arene and p-methoxycalix[8]arene octaamides encapsulate two strontium cations each. The binding geometries of the metal cations depend on the ligand size and on the counter anion used (chloride or picrate)

A novel self-assembled supramolecular architecture involving cation, anion and a calix[4]arene heteroditopic receptor

In the presence of potassium acetate the heteroditopic calix[4]arene receptor 1, in the 1,3-alternate structure and bearing two pentafluorophenyl amide groups as anion binders and a crown-5 polyether for cation complexation, self-assembles in an unexpected 2:2:2 (calixarene:cation: anion) supramolecular structure, as shown by X-ray crystal structure