Sodium Stearyl Fumarate's structure gives it effective lubricating properties at relatively low use levels (0.5--2.0% w/w), reducing friction between tablet granules and die-wall surfaces during compression. Notably, unlike magnesium stearate, it has been shown to cause substantially less disproportionation of weakly basic HCl salt drug substances --- a key advantage in formulations where excipient-induced pH shifts at the particle surface could compromise the salt form's chemical stability or dissolution behavior. Metabolically, it is hydrolyzed to stearyl alcohol (further oxidized to stearic acid) and fumaric acid, both naturally occurring constituents in the body and diet, supporting its favorable safety profile.
Sodium Stearyl Fumarate is the sodium salt of monostearyl fumarate, combining a long-chain stearyl (C18) hydrophobic tail with a fumarate head group. It is a widely used pharmaceutical lubricant excipient in tablet and capsule manufacturing, valued as a well-tolerated alternative to magnesium stearate.
| Chemical Name | Sodium Stearyl Fumarate (Sodium Octadecyl Fumarate) |
| CAS Number | 4070-80-8 |
| IUPAC Name | Sodium (2E)-4-(octadecyloxy)-4-oxobut-2-enoate |
| Molecular Formula | C22H39NaO4 |
| Molecular Weight | 390.53 g/mol g/mol |
| Boiling Point | 483.4°C |
Standard lubricant excipient reducing die-wall friction during tablet compression manufacturing.
Preferred lubricant choice for weakly basic HCl salt APIs, minimizing disproportionation risk compared to alkaline lubricants like magnesium stearate.
Applied in compound excipient systems (e.g., with crospovidone) for direct compression tablet formulations.
Used as a texturizing and stabilizing agent in select food and cosmetic product applications (FCC grade).
Pharm. Res.
Drug Dev. Ind. Pharm. (lubricant performance reference)
Yao Xue Xue Bao (formulation methodology reference)
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