Squalene is an organic compound. It is a triterpene with the formula C30H50. It is a colourless oil, although impure samples appear yellow. It was originally obtained from shark liver oil (hence its name, as Squalus is a genus of sharks). An estimated 12% of human sebum is squalene. Structurally it is composed of six isoprene units giving six double bonds and a linear C30 skeleton, molecular weight 410.72 g mol-1; the high degree of unsaturation makes it chemically reactive toward oxidation and amenable to hydrogenation to yield squalane. Squalene is non-polar, miscible with common lipids and organic solvents, and is processed for use in cosmetics, pharmaceutical excipients and adjuvant formulations; industrial and analytical considerations include control of peroxide value, iodine value and residual solvent content to maintain stability and performance.
Parent: Squalene
Typical refined squalene grades for cosmetic or pharmaceutical use are commonly reported at 95 to 99% squalene by weight, with the remaining fraction composed of related hydrocarbons, residual lipids and trace oxidation products. Representative impurity ranges for refined material are: saturates and hydrogenation products such as squalane 0.1 to 1.5%, sterols and unsaponifiables 0.1 to 1.0%, residual triglycerides and free fatty acids 0.2 to 1.0%, oxidation products including hydroperoxides, epoxides and aldehydes 0.01 to 0.5% depending on handling and antioxidant content, and residual solvent levels typically controlled to low ppm by specification. Analytical control is performed by GC or GC-MS for hydrocarbon profiling, HPLC for polar impurities, peroxide value testing for oxidation and ICP or AAS for trace metals.
Squalene occurs naturally in many sources: high concentrations are found in shark liver oil and in human sebum where it is about 12% of the lipid fraction, and it is also present in plant oils such as olive oil, amaranth seed oil, rice bran oil and wheat germ oil as well as in certain microorganisms.
Squalene is used as an emollient and skin-conditioning agent in cosmetics, as a solvent and intermediate in organic synthesis, and as an oil component in vaccine adjuvants and pharmaceutical formulations where its biocompatibility and biodegradability are advantageous.
Commercial squalene is obtained by extraction from natural sources or by biotechnological routes; crude extracts are refined by degumming, solvent extraction or distillation and then purified by molecular distillation and chromatographic methods to meet cosmetic or pharmaceutical specifications.
Key impurities to monitor are oxidation products (peroxides, epoxides, aldehydes) because they affect stability and safety, residual lipids and sterols which impact purity and sensory properties, and residual solvents or metals introduced during extraction; specifications and analytical methods vary by intended use.
