Simple stability-indicating validated HPLC method for diosgenin in cosmeceutical formulations with long term stability application for light and heat

A rapid, simple, precise and accurate stability-indicating analytical HPLC method was developed and validated for determination of diosgenin in cosmeceutical formulations. Modified extraction with suggested analytical method resulted in assurance of full recovery in all types of formulations. In this study, a Luna-C ₁₈ (4.6 mm x 150 mm, 5 μm particle size) column was employed using a mixture of distilled water and acetonitrile (15:85, v/v) as a mobile phase with a wavelength of 210 nm. Method validation was conducted based on ICH and USP guidelines. For a selectivity test, this method was shown to separate well with numerous interferences that were commonly employed as formulation excipients. An adequate linearity relationship (r ²=0.999) was obtained for diosgenin concentrations ranging from 0.05 to 1.0 mg mL ^-1. For all formulations, the accuracy percentage ranged from 99.21 to 101.52% and the precision was lower than 2%. These acceptance criteria indicated satisfactory validation results. Moreover, the proposed method was further applied for long-term and accelerated stability experiments in all formulations in forced stress conditions of light and heat.