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 quantitativ e determination of polysorbate 20 in various compositions of nasal solution s. This method is based on the acidic hydrolysis of the sorbitan laurate es ter followed by the HPLC determination of the free lauric acid. Using this method, polysorbate 20 can effectively be separated and quantitatively dete rmined in matrices containing a wide variety of preservatives, surfactants, and viscosity agents. Sample preparation involves a one-step hydrolysis wi th sulfuric acid and then a dilution with acetonitrile, prior to injection. The sample is analyzed on a 5-mu m octadecylsilane reverse-phase column wi th a mobile phase of acetonitrile: 0.025 M aqueous di-Sodium hydrogen phosp hate, 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, lin earity, 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. (C) 19 98 Elsevier Science B.V. All rights reserved.