Polymorph formation, transformation and crystal morphology were simultaneously tuned through a tailor-made additive via theoretical simulations combined with experimental methods.
This work combines experiments and simulations to investigate the inhibition effects of a surfactant on the nucleation and crystal growth rate of thiamine nitrate.
Data
on (solid + liquid) equilibrium of thiamine hydrochloride
hemihydrate (HH) in {water + (ethanol, acetone, or 2-propanol)} solvents
will provide essential support for industrial design and further theoretical
studies. In this study the solid–liquid equilibrium (SLE) was
experimentally measured over temperatures ranging from 278.15 to 313.15
K under atmospheric pressure by a dynamic method. For the temperature
range investigated, the equilibrium solubility of thiamine hydrochloride
hemihydrate (HH) varies with temperature and the composition of the
solvents. The experimental solubility was regressed with different
models including the modified Apelblat equation, λh equation, as well as NRTL equation. All the models gave good agreements
with the experimental results. On the basis of the solubility data
of HH, the thermodynamic properties of mixing process of HH with mixed
solvents were also discussed. The results indicate that the mixing
process of HH is exothermic. Besides, the model outwardly like the
Arrhenius equation was employed to quantitatively exhibit the relationship
between solubility and solvents mixtures polarity of solvents mixtures.
The solubility of form A metformin
hydrochloride (MET·HCl)
in water, methanol, ethanol, water + methanol, water + ethanol, water
+ acetone, and water + isopropanol at the temperatures ranging from
283.15 to 323.15 K was determined by gravimetric method. The experimental
results show that the solubility increases with the increase of temperature
and the initial water content of the binary solvents. The order of
solubility in the four aqueous solvent mixtures is water + methanol
> water + ethanol > water + isopropanol > water + acetone,
which is
mainly contributed by the hydrogen bond interactions. The modified
Apelblat model, CNIBS/R–K model, and Apelblat–Jouyban–Acree
model were used to correlate the solubility data. The results show
that the Apelblat model can correlate the solubility of four binary
solvents best, and all average relative deviations are less than 6%.
L-Valine crystallizes in a flake-like shape generally; however, compared with the flake-like products, spherulitic L-valine has better filterability, flowability, and bulk density and has potential for wider industrial applications in the future. In this study, L-valine spherulites have been successfully prepared by an evaporative crystallization method in the presence of no more than 0.5% hydroxypropyl methyl cellulose (HPMC). The spheroidization of L-valine proceeds via a layer-by-layer transformation from an initial flake-like shape to a petal-like form, and then it continues to grow into the final sphere-like shape. Molecular dynamics simulations show that HPMC interacts with hydrophilic (001) faces preferentially and promotes the continuous layer growth process. Only the substituent groups of hydroxypropyl and methyl exist simultaneously within a certain spatial distance and, in a viscosity of 40−50 mPa•s, can promote the formation of L-valine spherulites. The particle size increased with the increase in the HPMC dosage and decrease of temperature or evaporation rate. This effect of HPMC promoting the spherical formation provides a method to enrich the design of spherulites and new insights into the fabrication mechanism of spherulitic growth.
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