Authors:G. Bruni, V. Berbenni, C. Milanese, A. Girella, P. Cofrancesco, G. Bellazzi, and A. Marini
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.
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 (h2) 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.
Authors:J. Ginés, M. Arias, A. Rabasco, and P. Sánchez-Soto
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
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.
Authors:Luigi Campanella, Valentina Micieli, Mauro Tomassetti, and Stefano Vecchio
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 (Teu = 155.0 ± 0.5 °C, weu = 0.55 ± 0.02 and Teu = 53.3 ± 0.5 °C, weu = 0.32
), 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 < w1 < 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.
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
Authors:Reza Saberi, Azar Najafi, and Razi Naserifar
, 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