Effects of sodium β-sitosteryl sulfate on the phase behavior of dipalmitoylphosphatidylcholine

- Effects of β-sitosteryl sulfate on phase behavior of DPPC are discussed.
- β-sitosteryl sulfate greatly lowers the phase transition temperature of DPPC.
- It induces a modulated (ripple, Pβ) phase and a liquid ordered (Lo) phase.
- It effectively fluidizes the phosphatidylcholine membrane.
- Its fluidizing properties can be useful for formulating cosmeceuticals.

We have studied the phase behavior of dipalmitoylphosphatidylcholine (DPPC) containing sodium β-sitosteryl sulfate (PSO4). PSO4 was found to lower the phase transition temperature of DPPC to a higher degree than cholesterol or β-sitosterol. It also gave rise to the formation of a modulated (ripple) phase (Pβ) at low to moderate concentrations. At concentrations greater than 25 mol%, it completely changed the membrane into a fluid phase. This shows that PSO4 is capable of disordering the hydrocarbon chains of PC efficiently. The characteristics of PSO4 for fluidizing the membrane can be useful for the pharmaceutical and cosmetics industries.

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