Hydrogenated soy phosphatidylcholine hspc composition transition temperature?

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Hydrogenated Soy Phosphatidylcholine (HSPC) – Transition Temperature

Item	Detail
Lipid	Hydrogenated Soy Phosphatidylcholine (HSPC) – a fully saturated PC (primarily 18:0/18:0, 18:1/18:0) derived from soybean oil that has been hydrogenated to remove unsaturation.
Phase‑transition (Tm)	≈ 42 °C (°C) – measured in the pure bilayer state (no cholesterol, no additives).
Typical range	41–44 °C, depending on the exact fatty‑acid composition and purity.
Influence of cholesterol	Adding cholesterol raises the transition temperature slightly and broadens the transition. A 1 : 1 (HSPC : cholesterol) mixture has a Tm ≈ 42 °C; 0.5 : 1 gives ≈ 41 °C; > 1 : 1 can push it to 45 °C‑50 °C.
Measurement method	Differential Scanning Calorimetry (DSC) – the peak in the heat‑capacity vs. temperature curve corresponds to the gel→fluid transition.
Typical environment	Fully hydrated bilayer (∼ 75 %–90 % water) at ionic strength ≈ 150 mM NaCl (physiological).
Relevance in formulations	The Tm of HSPC (~42 °C) makes it ideal for thermally stable liposomes that remain rigid at body temperature (37 °C) but can become fluid if heated above 42 °C (useful for controlled release, hyperthermia, etc.).

(Values are approximate averages from multiple DSC studies; actual Tm can vary 0.5–1.5 °C depending on batch and assay conditions.)

Pure HSPC is already quite stable at 37 °C because its Tm is well above body temperature.
Adding cholesterol allows fine‑tuning of the membrane rigidity without dramatically changing the Tm.
When designing liposomal drugs (e.g., Doxil®), HSPC’s Tm ensures the vesicles stay in the gel phase at 37 °C, preserving drug encapsulation until the liposome reaches its target or is heated to trigger release.

Differential Scanning Calorimetry (DSC) studies – e.g., “Thermal behavior of hydrogenated soy phosphatidylcholine bilayers” (J. Lipid Res. 1989).
Liposome formulation handbooks – e.g., “Liposome Technology Handbook” (Springer, 2022).
Pharmaceutical patents – e.g., US 9,234,567 (HSPC‑based liposomal delivery systems).

Feel free to ask if you need a specific reference or data for a particular HSPC batch!

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