Hydrogenated Soy Phosphatidylcholine (HSPC) – Typical Composition
| Parameter | Typical Value | Notes |
|-----------|---------------|-------|
| Phospholipid class | > 97 % phosphatidylcholine (PC) | The commercial “HSPC” product is essentially pure PC; minor amounts of other soy‐derived phospholipids (PE, PS, PI) are below 1 %. |
| Fatty‑acid profile (molar % of the PC species) | Palmitic acid (C16:0) ~ 45–50 % | Saturated – the dominant chain in soy lecithin after hydrogenation. |
| | Stearic acid (C18:0) ~ 25–30 % | Saturated – also heavily represented. |
| | Oleic acid (C18:1) ~ 10–15 % | Monounsaturated; in HSPC the remaining unsaturation is largely converted to saturated forms, so this value is lower than in native soy PC. |
| | Linoleic acid (C18:2) ~ 5–8 % | Polyunsaturated; largely hydrogenated to stearic or oleic during the process. |
| | Minor/other fatty acids (e.g., linolenic, arachidic) < 5 % | Residual unsaturation that has not been fully hydrogenated. |
| Total unsaturation | < 15 % | The hydrogenation step removes the majority of double bonds, making HSPC much more stable in aqueous formulations. |
| Molecular weight | ~ 860–880 Da | Depends on the specific PC species (C16:0–C18:0 mixtures). |
| Melting point | ~ 30–35 °C | Reflects the high saturated‑fat content. |
Why the Numbers Matter
1. Stability – The high proportion of saturated fatty acids (palmitic & stearic) gives HSPC a higher melting point and makes it less prone to oxidation, which is why it’s a popular choice for liposomal drug delivery and sub‑micron emulsions.
2. Surface charge – With > 97 % PC, HSPC is essentially neutral (zwitterionic). This helps in forming stable, non‑ionic liposomes that are less likely to aggregate.
3. Hydrogenation efficiency – In commercial HSPC, the unsaturated PC species from soy lecithin (typically 30–35 % C18:1 and 10–15 % C18:2) are largely hydrogenated to C18:0 or C16:0, giving the product its characteristic “saturated” profile.
A Quick Reference – Avanti Polar Lipids HSPC (L-100)
| Component | Approx. % (w/w) | Comment |
|-----------|-----------------|---------|
| Phosphatidylcholine (PC) | 98–99 % | Pure PC fraction. |
| Phosphatidylethanolamine (PE) | 0.5–1 % | Minor residual. |
| Phosphatidylserine (PS) | 0.1–0.3 % | Minor residual. |
| Fatty acids (within PC) | 45 % C16:0, 30 % C18:0, 10 % C18:1, 5 % C18:2, 10 % others | Saturated‑rich. |
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Bottom Line
Hydrogenated soy phosphatidylcholine is essentially a fully saturated form of soy lecithin’s phosphatidylcholine, with a fatty‑acid distribution dominated by palmitic and stearic acids. The remaining unsaturated chains (oleic and linoleic) are largely converted to saturated analogs during hydrogenation, leaving a product that is very stable, neutral‑charged, and ideal for use in liposomes, nano‑emulsions, and other pharmaceutical preparations.