Glycerol Tripalmitate: Properties, Uses & Lab Guide

Glycerol tripalmitate is a fully saturated triglyceride composed of one glycerol backbone esterified with three palmitic acid (C16:0) chains, widely used as a lipid standard, metabolic substrate, and model compound in nutrition and formulation research.

Chemical Name

Glycerol tripalmitate (Tripalmitin)

Molecular Formula

C51H98O6

Molecular Weight

807.32 g/mol

CAS Number

555-44-2

Appearance

White to off-white crystalline powder or waxy solid

Melting Point

Approximately 65–66 °C

Solubility

Insoluble in water; soluble in hot chloroform, diethyl ether, and hot ethanol

SKU

G104095

Chemical Identity and Physical Properties

Glycerol tripalmitate, also known as tripalmitin or 1,2,3-tripalmitoylglycerol, is a symmetrical triglyceride in which all three hydroxyl groups of glycerol are esterified with palmitic acid (hexadecanoic acid, C16:0). Its IUPAC name is propane-1,2,3-triyl tris(hexadecanoate), and it carries CAS number 555-44-2.

At room temperature, glycerol tripalmitate exists as a white to off-white waxy solid or crystalline powder with a melting point in the range of approximately 65–66 °C. Because all three acyl chains are fully saturated C16 chains, the molecule packs efficiently into an ordered lamellar crystal structure, contributing to its relatively high melting point compared with unsaturated or mixed-chain triglycerides.

The compound is practically insoluble in water and cold lower alcohols. It dissolves readily in hot chloroform, diethyl ether, benzene, and hot ethanol, making standard lipid solvents appropriate for stock solution preparation. Its log P value is high, reflecting strong lipophilicity consistent with its all-saturated long-chain fatty acid composition.

Research Applications

Lipid metabolism and nutrition research: Glycerol tripalmitate serves as a well-defined model substrate for studying triglyceride digestion, absorption, and metabolism. Its uniform chain composition eliminates the complexity of mixed natural fats, enabling mechanistic studies of pancreatic lipase activity, intestinal absorption, and chylomicron assembly. Researchers investigating dietary saturated fat intake and cardiovascular risk factors commonly employ tripalmitin as a controlled lipid source in cell-based and animal models.

Analytical chemistry and method development: Because tripalmitin is a single-species triglyceride with a precisely defined molecular weight and chromatographic behavior, it is widely used as a reference standard in HPLC, GC-MS, and LC-MS/MS methods for triglyceride quantification in food, plasma, and tissue samples. It also serves as a calibrant for instrument response factor determination in lipid profiling workflows.

Formulation and material science: The well-characterized polymorphic transitions (α, β′, β forms) of glycerol tripalmitate make it a model compound for studying fat crystallization kinetics and polymorphism—topics critical in food science (chocolate, margarine texture) and pharmaceutical lipid-based drug delivery systems. It is used as a lipid matrix in solid lipid nanoparticle (SLN) formulation research and in wax-based controlled-release systems.

Cell biology: Tripalmitin emulsions are used to load intracellular lipid droplets in cell culture models studying lipotoxicity, adipogenesis, and lipid droplet dynamics, offering a model of saturated fat overload.

Handling, Storage, and Safety

Storage: Store glycerol tripalmitate as a solid at room temperature (15–25 °C) in a tightly sealed container, protected from moisture and light. Because the compound is a waxy solid with a melting point near 65–66 °C, avoid prolonged exposure to heat sources. Long-term storage under inert gas (nitrogen or argon) is recommended to prevent oxidative degradation of the ester bonds, although the fully saturated chains confer much greater oxidative stability than unsaturated triglycerides.

Solution preparation: To prepare stock solutions, warm an appropriate lipid solvent (chloroform, diethyl ether, or hot isopropanol) gently to aid dissolution. For aqueous emulsions required in biological assays, use a probe sonicator or high-shear homogenizer with a biocompatible emulsifier (e.g., Pluronic F-68 or lecithin) since the compound does not self-emulsify. Prepare fresh emulsions immediately before use, as particle size and stability can change on standing.

Safety: Glycerol tripalmitate is not classified as a hazardous substance under standard laboratory safety regulations; it has low acute toxicity and is structurally identical to components of natural dietary fat. Standard laboratory personal protective equipment (lab coat, gloves, eye protection) is nevertheless recommended. Consult the current Safety Data Sheet (SDS) provided by Aladdin Scientific before use.

Analytical Specifications and Quality

For research applications requiring high reproducibility—particularly analytical standards and formulation studies—purity is the primary specification of concern. Glycerol tripalmitate intended for use as a reference standard should be characterized by purity ≥99% as determined by GC or HPLC area normalization, with low levels of free fatty acid (FFA) and partial glycerides (mono- and diglycerides) as the principal impurities to monitor.

Key analytical parameters to verify upon receipt include: appearance (white waxy solid), melting point (consistent with ~65–66 °C), identity confirmation by IR or NMR spectroscopy, and purity by chromatographic method. Lot-specific certificates of analysis (CoA) from Aladdin Scientific provide batch-level data for these parameters and should be archived with experimental records.

Researchers using tripalmitin as an internal or external standard in quantitative lipidomics should verify the absence of isotope-labeled impurities and confirm molecular ion and fragmentation patterns by high-resolution MS prior to use in validated assays.

Frequently asked questions

What solvents are suitable for dissolving glycerol tripalmitate in the lab?

Glycerol tripalmitate dissolves readily in hot chloroform, diethyl ether, benzene, and hot ethanol or isopropanol. It is practically insoluble in water and cold lower alcohols. For biological assays requiring aqueous dispersions, emulsification with a biocompatible surfactant and sonication is necessary.

How should glycerol tripalmitate be stored to maintain stability?

Store the compound as a solid at room temperature (15–25 °C) in a tightly sealed container away from moisture and light. For long-term storage, an inert atmosphere (nitrogen or argon) is recommended. The fully saturated acyl chains provide good oxidative stability, but ester bonds can hydrolyze under prolonged exposure to moisture or acidic/basic conditions.

What makes glycerol tripalmitate a useful model compound in lipid research?

Glycerol tripalmitate is a single-species, fully saturated triglyceride with a precisely defined molecular structure, eliminating the positional and chain-length variability found in natural fats. This chemical uniformity makes it ideal for mechanistic studies of lipase activity, fat crystallization, lipid absorption, and as a chromatographic reference standard with a well-defined retention time and mass spectrum.

Can glycerol tripalmitate be used in solid lipid nanoparticle (SLN) formulations?

Yes, glycerol tripalmitate is widely used as a lipid matrix material in solid lipid nanoparticle research because of its well-characterized polymorphic behavior (α, β′, β crystal forms), defined melting point, and biocompatibility. Its crystallization kinetics and polymorph transitions can influence drug encapsulation efficiency and release profiles, making it a valuable tool for SLN formulation development.

What impurities should be monitored in glycerol tripalmitate for analytical use?

The principal impurities to monitor are free palmitic acid (free fatty acid content), and partial glycerides including 1,2-dipalmitin and 1-monopalmitin, which can arise from incomplete esterification or hydrolysis during storage. For high-accuracy quantitative work, verify purity by GC or HPLC and review the lot-specific Certificate of Analysis.

References

1. Hagemann, J.W. (1988). Thermal behavior and polymorphism of acylglycerides. In: Crystallization and Polymorphism of Fats and Fatty Acids, Garti N. & Sato K. (Eds.), Marcel Dekker, New York.
2. Muller, R.H., Mader, K., & Gohla, S. (2000). Solid lipid nanoparticles (SLN) for controlled drug delivery – a review of the state of the art. European Journal of Pharmaceutics and Biopharmaceutics, 50(1), 161–177. doi:10.1016/S0939-6411(00)00087-4
3. Christie, W.W. & Han, X. (2010). Lipid Analysis: Isolation, Separation, Identification and Lipidomic Analysis, 4th ed. Oily Press, Bridgwater, UK.

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