Validation of UV-visible spectrophotometric method for niclosamide in different media

Abstract

Purpose: To validate a UV-visible spectrophotometric technique for evaluating niclosamide (NIC) concentration in different media across  various values of pH. Methods: NIC was investigated using a UV-visible spectrophotometer in acidic buffer solution (ABS) of pH 1.2,  deionized water (DW), and phosphate buffer solution (PBS), pH 7.4. The characterization of NIC was done with differential scanning  calorimeter (DSC), powder X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The UV analysis was validated for  accuracy, precision, linearity, and robustness. Results: The DSC spectra showed a single endothermic peak at 228.43 °C (corresponding to  the melting point of NIC), while XRD and FTIR analysis confirmed the identity, crystallinity and purity of NIC. In all media, the  measured concentration of NIC was within ± 5 % of the actual value, which confirmed accuracy. The percentage relative standard  deviation values were < 1 %, reflecting the precision of the  method. The range of concentration measured was between 2 and 24 µg/mL,  and all coefficient of determination (R2 ) values were > 0.99, indicating the linearity of the established analytical method. The limit of  detection (LOD) and limit of quantification (LOQ) values were 0.122 and 0.407 µg/mL in ethanol, 0.530 and 1.766 µg/mL in ABS (pH 1.2),  0.224 and 0.747 µg/mL in DW, and 0.798 and 2.662 µg/mL in PBS, pH 7.4. The robustness was confirmed as the measured concentration  under slight changes in temperatures and wavelengths were insignificant (p > 0.05). Conclusion: Based on the results above, the UV- visible spectrophotometric method under investigation was validated to be accurate, precise, linear, and robust in all the different media  for the determination of NIC.