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Journal of Thermal Analysis and Calorimetry
Authors: G. Bruni, V. Berbenni, C. Milanese, A. Girella, P. Cofrancesco, G. Bellazzi, and A. Marini

Abstract  

In this work the solid-state characterization of anhydrous D-mannitol has been performed: α and β modifications can be distinguished only by XRPD and FTIR as they show melting temperature and enthalpy that are the same within the standard deviation. The understanding of the thermal behaviour of the δ form (obtained by re-crystallization in acetone) has required XRPD experiments performed at variable temperature. This form during heating undergoes a solid phase transition to α modification. By cooling a melted sample, under a wide range of experimental conditions, a very fast crystallization occurs. Independently of the starting crystal form (β or δ form), the re-crystallization of D-mannitol from melt always leads to α form.

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Abstract  

The dilution enthalpies of D-mannitol and D-sorbitol in aqueous sodium chloride solution at various concentrations have been determined by isothermal microcalorimetry at 298.15 K. The homogeneous enthalpic interaction coefficients over a quite large range of concentration of aqueous sodium chloride solutions have been calculated according to the excess enthalpy concept. The results show that enthalpic pairwise interaction coefficients (h 2) of D-mannitol and D-sorbitol are positive in aqueous sodium chloride solution and become more positive with increase of the concentration of sodium chloride. The results are interpreted in terms of the different conformations of the two polyols, solute-solute and solute-solvent interactions involved by solvent effects.

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Abstract  

Thermal analysis (DSC and HSM), and equilibrium solubility determinations were carried out to elucidate the mechanism of interaction at the solid state in the binary system triamterene-D-mannitol. Physical mixtures (5–90% w/w triamterene) and solid dispersions (5 up to 40% w/w triamterene) were prepared and studied. From DSC and HSM results, the thermal changes were associated with the variations in composition of the binary mixture, being more pronounced in the range 20–50% w/w. The binary phase diagram was proposed, although the exact position of the eutectic was uncertain. This is in accordance with a partial dissolution process detected by HSM. A linear increase in the solubility of triamterene with increasing aqueous mannitol concentration was obtained. The thermodynamic parameters of the solution properties were calculated, with an activation energy value of 96.081 kJ/mole. The solubilization increase was associated with complexation processes and hydrogen bonding formation.

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Solid–liquid phase diagrams of binary mixtures

Acetylsalicylic acid(1) + E(2) (E = salicylic acid, polyethylene glycol 4000, d-mannitol)

Journal of Thermal Analysis and Calorimetry
Authors: Luigi Campanella, Valentina Micieli, Mauro Tomassetti, and Stefano Vecchio

Abstract  

This study reports the investigation of three binary mixtures represented by acetylsalicylic acid (ASA) with its most important degradation product, salicylic acid (SA), and two of the most commonly used excipients (polyethylene glycol 4000 (PEG-4000) and d-mannitol (MA)). The liquidus and solidus equilibrium temperatures determined by DSC for pure components and solid binary mixtures at a fixed composition (mass fraction of ASA, w) were used to construct the corresponding solid–liquid phase diagrams. On the basis of the DSC results, the binary mixtures ASA/SA and ASA/PEG exhibit eutectic behavior (T eu = 155.0 ± 0.5 °C, w eu = 0.55 ± 0.02 and T eu = 53.3 ± 0.5 °C, w eu = 0.32  ± 0.01 ), respectively), while the binary mixture ASA/MA revealed the presence of a monotectic with a mean melting temperature of 162.2 °C in the range 0.2 < w 1 < 0.8. The composition of the two eutectics formed was confirmed by the related Tamman triangles. Finally, the liquidus curves of ASA/SA and ASA/PEG mixtures were also successfully predicted providing suitable polynomial (second-order) fitting equations.

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which DSC instrumentation can be used to aid quantitative data interpretation. Materials and methods d -Mannitol, carbamazepine (CBZ), nicatinamide (NCT) and sulfapyridine (all ALR grade) were purchased from Sigma

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2008 De Zeeuw , J.R. & Tynan , E.J. (1973 A ): Fermentation process for the production of D-mannitol. United States Patent 3 , 736, 229

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Eckhardt C Sellei IP Horváth 1963 Effect of 1,6-dibromo-1,6-dideoxy-D-mannitol on chronic granulocytic

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, and using D-Mannitol (Merck, Germany), each positive strain was subcultured in two plates at different molarities (0.5 and 1 M) for the osmotolerance assay. For both pathogenic tests, outgrowths of amoebae were checked by inverted microscopy [ 11 ,  17

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. Campanella , L , Micieli , V , Tomassetti , M , Vecchio , S . Solid-liquid phase diagrams of binary mixtures. Acetylsalicylic acid(1) + E(2) (E = salicylic acid, polyethylene glycol 4000, d -mannitol) . J Therm Anal Calorim 2010 99 : 887 – 892 10

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