The effect of hydrate formation on the solubility of theophylline in binary aqueous cosolvent systems

Gould, P. L.; Howard, John R.; Oldershaw, G. A.

doi:10.1016/0378-5173(89)90192-0

Cited by 17 publications

(14 citation statements)

References 13 publications

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“…Figure shows the measured solubility of TP monohydrate and TP-IV in water/ethanol mixtures taken from literature . In that reference, the liquid-phase composition was only analyzed regarding the TP concentration, whereas the composition of the solvent mixture was not analyzed after the slurry experiment.…”

Section: Resultsmentioning

confidence: 99%

“…The solubility values of the hydrate were obtained from solubility measurements where the hydrate was added in excess prior to the equilibration (Figure c). Thus, the measured solubility values will belong to a solvent-mixture composition different from the initial one.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 10 shows the measured solubility of TP monohydrate and TP-IV in water/ethanol mixtures taken from literature. 62 In that reference, the liquid-phase composition was only analyzed regarding the TP concentration, whereas the composition of the solvent mixture was not analyzed after the slurry experiment. The solubility measurements of the TP-IV were performed as shown in Figure 3a (TP-IV was added in excess, and TP-IV was obtained at thermodynamic equilibrium).…”

Section: T H Imentioning

confidence: 99%

“…It is worth noting that w ethanol refers to the mass fraction of ethanol in the CBZ-free system. 62 The solvent composition for solubility measurement of the TP monohydrate was corrected using a mass balance derived from Figure 4c, and the deviation is shown as error bars in the squares. The solid line is the PC-SAFT calculated hydrate solubility.…”

Section: T H Imentioning

confidence: 99%

“…Figure 10. Solubility of TP in a water/ethanol mixture (in mass fractions) at 303.15 K. ( □ ) The experimental solubility data of the TP monohydrate and (☆) TP-IV in the solvent mixture 62. The solvent composition for solubility measurement of the TP monohydrate was corrected using a mass balance derived from Figure4c, and the deviation is shown as error bars in the squares.…”

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Correctly Measuring and Predicting Solubilities of Solvates, Hydrates, and Polymorphs

Veith

Luebbert

Sadowski

2020

Crystal Growth & Design

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The formation of solvates, hydrates, or different polymorphs significantly alters the physicochemical properties of a target component (TC) (e.g., active pharmaceutical or agrochemical active ingredient), such as solubility and dissolution behavior. Thus, it is very important to know under which conditions a certain solvate, hydrate, or polymorph is formed. This information can be obtained from phase diagrams, which are usually based on solubility measurements. Possible pitfalls in measuring the solubility of TC hydrates or solvates in pure solvents and solvent mixtures are discussed, and strategies for obtaining reliable solubility data are proposed. To substantiate the proposed solubility-measurement strategies, a thermodynamic approach based on the Perturbed-Chain Statistical Associating Fluid Theory for modeling solvate/hydrate solubilities was developed. This approach allows identifying stability regions of solvates/hydrates and predicting solubilities of solvates/hydrates or of polymorphs in pure solvents and solvent mixtures. It was successfully verified for modeling the solubility of the indomethacin-methanol solvate in methanol and of the carbamazepine dihydrate in water. Furthermore, the solubility of carbamazepine dihydrate and theophylline monohydrate in water/ethanol mixtures was predicted in excellent agreement with experimental data.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: T H Imentioning

confidence: 99%

Section: T H Imentioning

confidence: 99%

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