Entrapment Efficiency of All-trans Retinoic Acid in Surfactant Vesicles

Abstract

Spontaneous vesicles of dicetyl dimethyl ammonium chloride (DCDAC) and its mixture with sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) are observed respectively in ethanol-water mixed solvents, which have been demonstrated by negative-staining transmission electric microscope (TEM) and atomic force microscope (AFM). Ethanol can promote the vesicle formation, especially to pure DCDAC surfactant system. The entrapment efficiency of the vesicles to all-trans retinoic acid (ATRA) was measured by the first order derivative spectrophotometry method. The entrapment efficiency of ATRA reaches 22% in 0.5 ethanol volume ratio solution when the concentration of DCDAC is 2.5 × 10⁻³ mol/L. In the same solvents, the entrapment efficiency could be as high as 62% in 1:9 (molar ratio) DCDAC/AOT mixtures when the total concentration of surfactants is 3.0 × 10⁻³ mol/L.

Keywords:

• All-trans retinoic acid (ATRA)
• dicetyl dimethyl ammonium chloride (DCDAC)
• entrapment efficiency
• sodium bis-(2-ethylhexyl) sulfosuccinate (AOT)
• vesicle

This work was supported by Natural Science Foundation of Shandong Province (Y2006B29).

Notes

C – molar concentration of DCDAC aqueous solution; Ve – volume fraction of ethanol.

C _t – the total molar concentration of DCDAC and AOT water solution.