Solubility and thermodynamic function of vitamin D3 in different mono solvents

In this study, the solubility of a fat soluble vitamin (vitamin D3) was measured in eleven different mono solvents including “water, ethanol, 2-propanol (IPA), 1-butanol, 2-butanol, 2-(2-ethoxyethoxy) ethanol [Transcutol®], ethylene glycol (EG), propylene glycol (PG), polyethylene glycol-400 (PEG-400), ethyl acetate (EA) and dimethyl sulfoxide (DMSO)” at temperatures “T = 273.2 K to 298.2 K” and “atmospheric pressure p = 0.1 MPa”. Experimental solubility data of vitamin D3 in mole fraction were correlated well with “Van't Hoff and Apelblat models” with mean percent deviations of < 5.0%. The solubilities of vitamin D3 in mole fraction at “T = 298.2 K” were obtained highest in Transcutol® (4.03 × 10− 1) followed by IPA (2.45 × 10− 1), EA (1.95 × 10− 1), 2-butanol (1.87 × 10− 1), ethanol (1.77 × 10− 1), 1-butanol (1.69 × 10− 1), PEG-400 (2.91 × 10− 2), DMSO (7.23 × 10− 3), PG (3.37 × 10− 3), EG (5.24 × 10− 4) and water (1.03 × 10− 6). Thermodynamic treatment of solubility data of vitamin D3 by “Apparent thermodynamic analysis” indicated an “endothermic and entropy-driven dissolution” of vitamin D3 in all mono solvents investigated. Based on the results of this study, vitamin D3 has been considered as practically insoluble in water, sparingly soluble in DMSO, PG and PEG-400, poorly soluble in EG and very soluble in ethanol, IPA, EA, 1-butanol, 2-butanol and Transcutol®.