Detection of Fatty Acids in Polysorbate 80

The problem of pharmaceutical excipients has plagued domestic pharmaceutical preparation manufacturers in recent years, and the quality control of excipients has attracted the attention of regulatory agencies and manufacturers. There are specific requirements for physical and chemical testing indicators of the excipient varieties in Chinese Pharmacopoeia, and studies related to the testing of excipients which have been carried out. Here is a case to share with you: polysorbate 80 fatty acid testing.

Polysorbate 80 is a nonionic surfactant, which is a polyoxyethylene 20 sorbitan oleate polymerized from sorbitan oleate and ethylene oxide. Because polysorbate 80 has a good solubilizing effect on lipophilic drugs, it is often used as a solubilizer or emulsifier for injections and oral liquids and is a commonly used excipient for pharmaceutical preparations. Polysorbate 80 is usually a mixture, and the composition of the fatty acid part in its molecular structure is mostly different. It takes oleic acid as the main component and also contains other fatty acids, such as myristic acid, palmitic acid, palmitoleic acid, stearic acid, linoleic acid and linolenic acid.

The 2015 version of the Chinese Pharmacopoeia adds the requirements of polysorbate 80 which the 2020 version of the Chinese Pharmacopoeia adopts. Polysorbate 80 has fatty acid content requirements: myristic acid (≤5.0%), palmitic acid (≤16.0%), palmitoleic acid (≤8.0%), stearic acid (≤6.0%), linoleic acid (≤18.0%) and linolenic acid (≤4.0%), consistent with EP, BP and other requirements.

With reference to the pretreatment method of alkali-catalyzed boron trifluoride/methanol derivatization in the Chinese Pharmacopoeia, and following the gas chromatographic conditions specified in the Pharmacopoeia, a gas chromatograph is used to establish a method for determining the fatty acid composition of e433 polysorbate 80. Three polysorbate 80 products are tested.

Here is the conclusion:

The content of oleic acid in polysorbate 80 is directly related to its purity. The fatty acids in polysorbate 80 are detected by gas chromatography. The experimental results effectively reflect the composition and content of fatty acids in it, which can be used for quality control of pharmaceutical excipients, thereby reducing the risk of clinical medication.