Solubility Determination, Model Correlation, and Solvent Effect Analysis of Nisoldipine in Different Solvent Systems at a Series of Temperature

et al. 2021

The mole fraction solubility data of N-acetyl-l-proline in 16 neat solvents (water, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, n-pentanol, acetone, 2-butanone, acetonitrile, dichloromethane, methyl acetate, ethyl acetate, and 1,4-dioxane) covering a temperature range of 283.15–323.15 K were measured by the static gravimetric method. The polymorphism of N-acetyl-l-proline was investigated by the powder X-ray diffraction test and the patterns show that there are two polymorphs within the studied solid–liquid equilibrium systems. The increasing temperature shows a positive effect on N-acetyl-l-proline solubility in all of the solvents and the largest increasing rate is observed in acetonitrile with an increase of 16-fold. The solubility behavior was found to be influenced by five factors including polarity, hydrogen bonding, solvent–solvent interactions, molecular construction, and viscosity. Two thermodynamic models, i.e., the modified Apelblat model and the Yaws model, were used for the correlation of solubility data. To evaluate the fitting results, the average relative deviation (ARD) and root-mean-square deviation (RMSD), as well as the Akaike information criterion (AIC) and Akaike weights, were computed for each model.

Section: Resultsmentioning

confidence: 99%

Solubility Behavior and Polymorphism of N-Acetyl-l-proline in 16 Individual Solvents from 283.15 to 323.15 K

Huang

et al. 2021

“…Except for solvent–solute and solvent–solvent interactions, the dissolution behavior of Boc-L-proline could also be influenced by the molecular structures of the solvent and solute. Compounds that have similar chemical constructions are more likely to be dissolved by each other, which may result in the increase in solubility. , There are three methyl groups on the tert -butoxycarbonyl group of the Boc-L-proline molecule, which may lead to the strong association between methanol (also contains methyl) and Boc-L-proline molecules. This may be the reason for the highest solubility of methanol among the 14 solvents.…”

Section: Results and Discussionmentioning

confidence: 99%

Solubility Behavior of Boc-L-proline in 14 Pure Solvents from 283.15 to 323.15 K

Wang

et al. 2021

The data on the solubility of Boc-L-proline in 14 monosolvents, namely, water, ethanol, methanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, acetone, acetonitrile, butanone, ethyl acetate, methyl acetate, and dichloromethane (DCM), were measured by a static gravimetric method covering the temperature range of 283.15–323.15 K. The equilibrated solid phase of Boc-L-proline in all the solvent systems was characterized via the test of X-ray powder diffraction. The solubility values in all the solvents are positively correlated with the temperature. The dissolution behavior was affected by the combined effects of four factors consisting of solvent polarity, formation of hydrogen bonds, solvent–solvent intermolecular interactions (represented by cohesive energy density), and molecular structures of solvents and the solute. Additionally, the Yaws model and modified Apelblat model were utilized to fit the data of solubility, and the values of Akaike information criterion as well as Akaike weights were calculated to evaluate the relative applicability of the two solubility models. The results show that the Yaws model could give a better correlation result for the solubility data than the model of modified Apelblat.

“…By comparing the solubility data and viscosity values of the selected solvents, it is found that the solubility in eight alcohol solvents, two ketone solvents, and two ester solvents decreased with the increase of viscosity. Compounds with similar structures can dissolve each other better and lead to the enhancement of the solubility, which is the principle of “like dissolves like”. , It can be inferred that the solubility in acetone and 2-butanone is higher than that in methyl acetate and ethyl acetate, which may be because the same carbonyl group existed in the ketones and NAM molecules. In addition, the high solubility of 1,4-dioxane may be speculated as follows: NAM can be used as a hydrogen bond donor and a hydrogen bond acceptor, leading to the formation of intramolecular hydrogen bonds, thus becoming a ring structure.…”

Section: Resultsmentioning

confidence: 99%

Solubility Behavior and Polymorphism of N-Acetyl-dl-methionine in 16 Individual Solvents from 283.15 to 323.15 K

Huang

et al. 2021

The mole fraction solubility data of N-acetyl-dl-methionine in 16 pure solvents at T = 283.15–323.15 K were measured using the static gravimetric method under a pressure of 98.8 kPa. The polymorphism of N-acetyl-dl-methionine was studied by X-ray powder diffraction analysis, and the results show that there may exist two polymorphs in the studied solid–liquid equilibrium systems. The solubility increased with increasing temperature, and the largest solubility value was obtained in methanol, followed by ethanol > n-propanol > isopropanol > n-butanol > sec-butanol > isobutanol > n-pentanol > acetone > 2-butanone > water > methyl acetate > ethyl acetate > dichloromethane (except for 1,4-dioxane and acetonitrile, which intersect with other solvents). The above solubility behavior is affected by the mutual constraints of polarity, hydrogen bonding, cohesive energy density, viscosity, and molecular structure. In addition, the KAT-LSER model was applied to analyze solute–solvent and solvent–solvent intermolecular interactions. To mathematically represent the measured solubility data, the modified Apelblat model and Yaws model were employed. The average relative deviation (ARD), root-mean-square deviation (RMSD), Akaike information criterion (AIC), and Akaike values of each model were calculated to evaluate the fitting outcomes.