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. 2023 May 5;16(9):3550.
doi: 10.3390/ma16093550.

Study on Reversible Solubilization by Adjusting Surfactant Properties

Youichi Takata  1 , Amu Uchikura  1
Affiliations

Study on Reversible Solubilization by Adjusting Surfactant Properties

Youichi Takata et al. Materials (Basel). .

Abstract

Solubilization allows us to dissolve hydrophobic materials in water and to carry them to where they are needed. The purpose of this study is to control solubilization, especially the release of solubilized materials, via external stimulation. An amphoteric surfactant, dodecyldimethyl(3-sulfopropyl)ammonium hydroxide inner salt (SB-12), was employed, and a pH change was chosen as the external stimulus. We measured the surface tension of an SB-12 solution via the Wilhelmy method, and the absorbance of a solubilized solution was determined using UV-Vis spectroscopy at various pH values. The surface tension was almost the same at any pH, contrary to our expectations. This result suggests that the adsorption behavior and micelle formation of SB-12 were not affected by pH very much. On the other hand, the solubilization behavior remarkably depended on the pH. In particular, the solubilization ability under the basic condition was much larger than that under the acidic and neutral conditions. Taking advantage of such a difference in solubilization ability under some pH conditions, the solubilized material could be completely removed from the solution. Thus, we clarified the mechanism of release for solubilized materials due to a pH change.

Keywords: amphoteric surfactant; controlled release; micelle; reversible solubilization; surface tension.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Surface tension versus molarity of SB-12 in distilled water (pH = 6.0) curve.
Figure 2
Figure 2
Surface density versus molarity of SB-12 in distilled water (pH = 6.0) curve.
Figure 3
Figure 3
Surface pressure versus surface area occupied by an adsorbed SB-12 molecule at air/distilled water (pH = 6.0) surface.
Figure 4
Figure 4
Surface tension versus molarity of SB-12 curves at pH = 1.2 (red), 6.0 (gray), and 12.5 (blue).
Figure 5
Figure 5
(a) Surface density versus molarity of SB-12 curves and (b) surface pressure versus surface area occupied by adsorbed SB-12 molecule curves at pH = 1.2 (red), 6.0 (gray), and 12.5 (blue).
Figure 6
Figure 6
(a) Absorbance versus molarity of SB-12 solution curves at pH = (1) 1.2, (2) 6.0, (3) 11.0, (4) 12.0, (5) 12.3, and (6) 12.5. (b) Absorbance versus pH of SB-12 solution curves at constant molarity (1) 1.00, (2) 3.00, (3) 5.00, (4) 7.00, (5) 9.00, and (6) 15.0 mmol L−1.
Figure 7
Figure 7
Photograph of filtrate after (a) 0.1 mol L−1 hydrochloric acid, (b) 0.05 mol L−1 hydrochloric acid, (c) 0.01 mol L−1 hydrochloric acid, and (d) water were added into the basic solution containing solubilized Sudan III. The volume ratio of added liquid to the whole solution, from left to right, is 0.167, 0.333, 0.500, 0.667, and 0.833.
Figure 8
Figure 8
Absorbance of solution in Figure 7 after (a) 0.1 mol L−1 hydrochloric acid, (b) 0.05 mol L−1 hydrochloric acid, (c) 0.01 mol L−1 hydrochloric acid, and (d) water were added to the basic solution containing solubilized Sudan III. The black and red plots yield the absorbance of solution and pH values, respectively.
See this image and copyright information in PMC

References

    1. Thummar A.D., Sastry N.V., Verma G., Hassan P.A. Aqueous block copolymer-surfactant mixtures—Surface tension, DLS and viscosity measurements and their utility in solubilization of hydrophobic drug and its controlled release. Colloids Surf. A. 2011;386:54–64. doi: 10.1016/j.colsurfa.2011.06.027. - DOI
    1. Parmar A., Chavda S., Bahadur P. Pluronic–cationic surfactant mixed micelles: Solubilization and release of the drug hydrochlorothiazide. Colloids Surf. A. 2014;441:389–397. doi: 10.1016/j.colsurfa.2013.09.018. - DOI
    1. Singla P., Chabba S., Mahajan R.K. A systematic physicochemical investigation on solubilization and in vitro release of poorly water soluble oxcarbazepine drug in pluronic micelles. Colloids Surf. A. 2016;504:479–488. doi: 10.1016/j.colsurfa.2016.05.043. - DOI
    1. Pillai S.A., Sheth U., Bahadur A., Aswal V.K., Bahadur P. Salt induced micellar growth in aqueous solutions of a star block copolymer Tetronic® 1304: Investigating the role in solubilizing, release and cytotoxicity of model drugs. J. Mol. Liq. 2016;224:303–310. doi: 10.1016/j.molliq.2016.09.091. - DOI
    1. Sastry N.V., Singh D.K., Thummar A.D., Verma G., Hassan P.A. Effect of hydrocarbon surfactants on dexamethasone solubilization into silicone surfactant micelles in aqueous media and its release from agar films as carriers. J. Mol. Liq. 2017;225:11–19. doi: 10.1016/j.molliq.2016.11.034. - DOI

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