Usefulness of Urea as a Means of Improving the Solubility of Poorly Water-Soluble Ascorbyl Palmitate

Inoue, Yutaka; Niiyama, Daichi; Murata, Ikuo; Kanamoto, Ikuo

doi:10.1155/2017/4391078

Cited by 6 publications

(9 citation statements)

References 19 publications

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“…Organic bases have been employed in the preparation of CD ternary complexes, but none has reported the incorporation of urea [29]. Complexes of ASCP and UR prepared using the evaporation method were found to improve the solubility of ASCP [30]. The improvement of solubility in aqueous solvents by the formation of inclusion complexes of ASCP and γCD using the grinding mixture method has also been reported [31].…”

Section: Introductionmentioning

confidence: 99%

Preparation and Spectroscopic Characterization of Ternary Inclusion Complexes of Ascorbyl Palmitate and Urea with γ-Cyclodextrin

et al. 2023

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A three-component inclusion complex of ascorbyl palmitate (ASCP), urea (UR), and γ-cyclodextrin (γCD) with a molar ratio of 1/12 has been prepared for the first time using the evaporation method (EVP method) and the grinding and mixing method (GM method). Also, we investigated changes in the physicochemical properties of the three-component complexes. The powder X-ray diffraction (PXRD) measurements showed ASCP, UR, and γCD characteristic peaks in the physical mixture (PM) (AU (ASCP/UR = 1/12)/γCD = 1/2). In GM (AU (ASCP/UR = 1/12)/γCD = 1/1), new diffraction peaks were observed around 2θ = 7.5° and 16.6°, while characteristic peaks derived from EVP (ASCP/UR = 1/12) were observed at 2θ = 23.4° and 24.9°. On the other hand, new diffraction peaks at 2θ = 7.4° and 16.6° were observed in GM (1/2). In the differential scanning calorimeter (DSC) measurement, an endothermic peak at around 83 °C was observed in the GM (1/1) sample, which is thought to originate from the phase transition of urea from the hexagonal to the tetragonal form. An endothermic peak around 113.9 °C was also observed for EVP (ASCP/UR = 1/12). However, no characteristic phase transition-derived peak or EVP (ASCP/UR = 1/12)-derived endothermic peak was observed in GM (1/2). Near infrared (NIR) spectroscopy of GM (1/2) showed no shift in the peak derived from the CH group of ASCP. The peaks derived from the NH group of UR shifted to the high and low wavenumber sides at 5032 cm−1 and 5108 cm−1 in EVP (ASCP/UR = 1/12). The peak derived from the OH group of γCD shifted, and the peak derived from the OH group of ASCP broadened at GM (1/2). These results suggest that AU (ASCP/UR = 1/12)/γCD prepared by the mixed grinding method formed inclusion complexes at the molar ratio (1/2).

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Section: Introductionmentioning

confidence: 99%

Preparation and Spectroscopic Characterization of Ternary Inclusion Complexes of Ascorbyl Palmitate and Urea with γ-Cyclodextrin

et al. 2023

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“…Urea in aqueous solutions presents unique properties that are relevant to many different scientific communities. Aside from being highly water-soluble, urea has been shown to enhance the solubility of hydrocarbons in water, − cause proteins to denature, , and prevent micellar aggregation , by mediating the critical micelle concentration of various surfactants. , Because of these findings, numerous studies abound that examine how urea perturbs the local hydrogen bond network of water. , …”

Section: Introductionmentioning

confidence: 99%

Urea Disrupts the AOT Reverse Micelle Structure at Low Temperatures

Miller

Levinger

2022

Langmuir

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Aside from its prominent role in the excretory system, urea is also a known protein denaturant. Here, we characterize urea as it behaves in confined spaces of AOT (sodium bis(2-ethylhexyl) sulfosuccinate) reverse micelles as a model of tight, confined spaces found at the subcellular level. Dynamic light scattering revealed that low temperatures (275 K) caused the smallest of the reverse micelle sizes, w 0 = 10, to destabilize and dramatically increase in apparent hydrodynamic diameter. We attribute this to urea embedded into the surfactant interface as confirmed by 2D 1 H-NOESY NMR spectroscopy. This increase in size in turn caused the hydrogen exchange between urea and water within the nanosized reverse micelles to increase as measured by 1D EXSY-NMR. A minimal enlarging effect and no increase in hydrogen exchange were observed when aqueous urea was introduced into w 0 = 15 or 20 reverse micelles, suggesting that this effect is unique to particularly small-diameter spaces (∼7 nm).

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“…UR generally exists as a polymorph with tetragonal and hexagonal crystal structures in the solid state. UR, in a hexagonal crystal structure, has been reported to improve solubility by enclosing the guest molecules within its pores [14]. It has also been shown that UR can form co-crystals with drugs such as benzamide and complex with palmitic acid [15,16].…”

Section: Introductionmentioning

confidence: 99%

Preparation, Characterization, Solubility, and Antioxidant Capacity of Ellagic Acid-Urea Complex

et al. 2022

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Ellagic acid (EA), a natural polyphenol found in berries, has high antioxidant capacity. This study aimed to improve EA solubility by complex formation with urea (UR) using solvent an evaporation method and evaluate its solubility, antioxidant capacity, and physical properties. The solubility test (25 °C, 72 h) showed that the solubility of EVP (EA/UR = 1/1) was approximately two-fold higher than that of EA (7.13 µg/mL versus 3.99 µg/mL). Moreover, the IC50 values of EA and EVP (EA/UR = 1/1) (1.50 µg/mL and 1.30 µg/mL, respectively) showed higher antioxidant capacity of EVP than that of EA. DSC analysis revealed that the UR peak at 134 °C disappeared, and a new endothermic peak was observed at approximately 250 °C for EVP (EA/UR = 1/1). PXRD measurements showed that the characteristic peaks of EA at 2θ = 12.0° and 28.0° and of UR at 2θ = 22.0°, 24.3°, and 29.1° disappeared and that new peaks were identified at 2θ = 10.6°, 18.7°, and 26.8° for EVP (EA/UR = 1/1). According to 2D NOESY NMR spectroscopy, cross-peaks were observed between the -NH and -OH groups, suggesting intermolecular interactions between EA and UR. Therefore, complexation was confirmed in EA/UR = 1/1 prepared by solvent evaporation, suggesting that it contributed to the improvement in solubility and antioxidant capacity of EA.

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Usefulness of Urea as a Means of Improving the Solubility of Poorly Water-Soluble Ascorbyl Palmitate

Cited by 6 publications

References 19 publications

Preparation and Spectroscopic Characterization of Ternary Inclusion Complexes of Ascorbyl Palmitate and Urea with γ-Cyclodextrin

Preparation and Spectroscopic Characterization of Ternary Inclusion Complexes of Ascorbyl Palmitate and Urea with γ-Cyclodextrin

Urea Disrupts the AOT Reverse Micelle Structure at Low Temperatures

Preparation, Characterization, Solubility, and Antioxidant Capacity of Ellagic Acid-Urea Complex

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