Spectrophotometric determination of ichthammol in topical formulations

Background and Aims: This study developed a new, simple, and rapid spectrophotometric method for determining ichthammol as a local antiseptic in topical formulations. The developed spectrophotometric method for determining ichthammol was applied to topical formulations.Methods: The linearity range of the ichthammol was 5.0-50.0 μg/mL at a wavelength of 235 nm. Ethanol:water (50:50; v/v) was used as the solvent. The method was validated using the limit of quantification, limit of detection, linearity, selectivity, robustness, recovery, precision, stability, and accuracy of the method using the International Conference on Harmonisation guidelines for validation of analytical procedures: text and methodology Q2 (R1).Results: The limits of detection and quantification were calculated to be 0.044 μg/mL and 0.148 μg/mL, respectively. Intra-day and inter-day relative standard deviation values were calculated to be less than 1.024 %. The assay recovery and precision of ichthammol from topical formulations at 5.0, 20.0, and 50.0 μg/mL were evaluated. The mean recoveries for ichthammol in the topical formulation were calculated at 97.944-99.860%. It was determined that the ichthammol sample solution was stable for 24 h at 4.0°C. The validated method was applied to the cream formulation, and the amount of ichthammol in the cream was determined to be 97.442%.Conclusion: The validated method was successfully applied to determine ichthammol in topical formulations. The proposed method is reproducible and reliable and can be safely used for routine analysis.