Quantitative determination of polysorbate 20 in nasal pharmaceutical preparations by high-performance liquid chromatography

A specific reverse-phase HPLC method has been developed for the quantitative determination of polysorbate 20 in various compositions of nasal solutions. This method is based on the acidic hydrolysis of the sorbitan laurate ester followed by the HPLC determination of the free lauric acid. Using this method, polysorbate 20 can effectively be separated and quantitatively determined in matrices containing a wide variety of preservatives, surfactants, and viscosity agents. Sample preparation involves a one-step hydrolysis with sulfuric acid and then a dilution with acetonitrile, prior to injection. The sample is analyzed on a 5-microm octadecylsilane reverse-phase column with a mobile phase of acetonitrile: 0.025 M aqueous di-Sodium hydrogen phosphate, pH = 2.8 (75:25). The column effluent is monitored by UV detection at 210 nm. The validity of the method has been verified with specificity, linearity, recovery, method- and system precisions data. The method is linear for polysorbate 20 from 2.5 to 125 mg ml(-1) range. The limit of detection and limit of quantitation are 0.41 and 0.61 mg ml(-1), respectively.