Gustavo A. Monti

Synthesis and Characterization of Al-MCM-41 and Al-MCM-48 Mesoporous Materials

A novel route in the synthesis of Al-MCM-41 and Al-MCM-48, using tetraethoxysilane (TEOS) and sodium aluminate (NaAlO2) as Si and Al source has been obtained. The effect of surfactant nature and the synthesis conditions such as surfactant/Si ratio and hydrothermal treatment time on the formed mesostructure regularity has been studied. Different methods of template removal have also been evaluated. The samples were characterized by X-ray diffraction, nitrogen physisorption, FT-IR, and solid-state MAS NMR spectroscopy.

Preparation and characterization of aluminium - containing MCM-41

Fil: Eimer, Griselda Alejandra. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Centro de Investigacion y Tecnologia Quimica. Universidad Tecnologica Nacional. Facultad Regional Cordoba. Centro de Investigacion y Tecnologia Quimica; Argentina

Characterization of the solubility and solid‐state properties of saccharin salts of fluoroquinolones

Saccharinates salts of the fluoroquinolone antibiotics norfloxacin, ciprofloxacin, ofloxacin, and enrofloxacin were obtained as pure crystalline anhydrous solids with sweet taste. The products were characterized by one- ((13)C) and two-dimensional ((1)H-(13)C) dimensions solid state Nuclear Magnetic Resonance and infrared spectroscopy showing ionic interactions between the saccharine amide and the fluoroquinolone piperazine. Several intermolecular bindings were also identified. Thermal behavior and powder X-ray diffraction provided complementary evidences of salt formation. The series of products showed improved properties with respect to water solubility. A solubility model was developed. These salts would be a good way forward to developing more suitable formulations of these APIs.

Crystallographic, thermal and spectroscopic characterization of a ciprofloxacin saccharinate polymorph.

A new polymorphic form of ciprofloxacin saccharinate (CIP-SAC II) is presented, and compared with CIP-SAC I, a different polymorph which we had previously reported. The characterization techniques used were single crystal and powder X-ray diffraction, differential scanning calorimetry, thermogravimetry analysis and infrared and (13)C solid-state nuclear magnetic resonance spectroscopy. The results obtained from these techniques are consistent. Differential scanning calorimetry and thermogravimetric analysis showed that the reaction between the precursors is completed and the crystalline forms of both salts obtained (I and II) are highly pure. Infrared spectroscopy gave clear evidence of a salt formation. Solid-state nuclear magnetic resonance spectroscopy would indicate some degree of qualitative similarity in the intermolecular interaction scheme in both polymorphs, while thermal analysis data might indicate a difference in quantitative terms. A thorough single crystal structure determination of the new form CIP-SAC II allowed disclosing the most important inter- and intramolecular interactions.

Single crystal structure, solid state characterization and dissolution rate of terbinafine hydrochloride.

Terbinafine hydrochloride (TH), a poorly water soluble antifungal agent, was characterized by solid state techniques including differential scanning calorimetry, thermogravimetry, X-ray powder diffraction, optical and electron microscopies, Fourier transform infrared, Raman and solid-state nuclear magnetic resonance spectroscopies and intrinsic dissolution rate (IDR). A colorless single crystal of TH was grown from an ethanol:water solution and its crystalline structure was determined through X-ray single crystal diffraction. Also, a new crystal habit of TH was obtained through the slow solvent evaporation technique revealing a needle-like shape. A comparison between the IDR results for the TH raw material and TH needle-like crystal revealed lower values for the new crystal habit, which can be attributed to the preferential orientation of the crystals in the compressed disks.

Analysis of cross-polarization dynamics between1H and19F in Viton fluoroelastomer using solid-state19F magic angle spinning and1H →19F cross-polarization magic angle spinning NMR

The cross‐polarization dynamics between 1H and 19F in a Viton‐type fluoroelastomer were studied using 19F magic angle spinning (MAS) and 1H → 19F cross‐polarization (CP)/MAS NMR at 188.29 MHz. The phenomenological theory of spin thermodynamics based on the spin temperature hypothesis was employed to describe the polarization transfer between the 1H and 19F spin baths. Simultaneous fitting of the evolution of magnetization in the standard CP and a modified CP(TORQUE) experiment, using the exact solutions of the equations for the spin thermodynamics, gave unique sets of the parameters THF,

Proton spin-diffusion in PVDF: a 1H–19F CP/MAS NMR study

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Dissolution properties, solid-state transformation and polymorphic crystallization: progesterone case study.

and

Evaporation Kinetics in Swollen Porous Polymeric Networks

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Studies of pilocarpine:carbomer intermolecular interactions

for five separate peaks in the 19F spectra. The values of