Spectroscopic Quantification of Surfactants in Solid Lipid Nanoparticles

Objective Solid lipid nanoparticles (SLN) mainly consist of lipids and surfactants. However, the toxicity of surfactant cannot be ignored, as the surfactant may cause unexpected side effect. This study established model SLN with different surfactants, Tween 80 (T80) and poloxamer 188 (P188). It was aimed to establish ultraviolet-visible (UV-Vis) spectroscopy methods for quantifying the contents of T80 and P188 in the model SLN. Methods The model SLN were produced by emulsification-precipitation method, and their particle size distribution was analyzed. The calibration curves for the contents of T80 and P188 were established. Surfactants in the model SLN were extracted by ultrasonication, and UV-Vis spectroscopy methods were utilized for quantification of surfactants in SLN. Results The deviation of precision and accuracy in P188 and T80 assay were acceptable, which indicated the method could be employed in sample quantification. Ten minutes was considered as the optimal ultrasonication time. And the contents of P188 and T80 were successfully measured by the established UV-Vis methods. Conclusion The UV-Vis spectroscopy methods were developed for the quantification of T80 and P188 in the model SLN. It is expected that the methods could be extended to more SLN systems and applied for the quantification of other surfactants.