Advanced HPTLC Method Development for Silibinin Analysis in Nanoformulated Scaffolds: A Box-Behnken Approach

Silibinin (silybin), a bioactive component derived from the seeds of milk thistle (Silybum marianum), is recognized for its diverse pharmacological properties, including antioxidant, anti-inflammatory, and hepatoprotective effects. Given its therapeutic significance, accurately quantifying silybin in various formulations is essential. High-performance thin-layer chromatography (HPTLC) is a powerful analytical technique frequently used for this purpose. In this study, an HPTLC method was validated according to the International Council for Harmonization (ICH) guidelines to determine the concentration of silybin. The design of experiments (DoE), specifically the Box-Behnken design, was employed to optimize and understand the influence of critical method variables.

The HPTLC method validation was performed using silica gel F254 HPTLC plates. The variables investigated included the composition of the mobile phase (% v/v), saturation time (minutes), and temperature in degree Celsius (°C), with the Box-Behnken design for optimization. The mobile phase consisted of chloroform, acetone, and formic acid in a 7:2:1 (v/v) ratio. Both the formulated scaffold and standard drug were applied to the plates, which were then processed in a twin chamber. After development, the plates were scanned at 288 nm using the Camag TLC Scanner IV with Vision CATS software.

The validated HPTLC method demonstrated a strong linear relationship within the silybin concentration range of 2-10 μg/mL. The limit of detection (LOD) and limit of quantification (LOQ) for silybin were determined to be 0.469 and 1.423 μg/mL, respectively. Recovery studies indicated that the method provided accurate quantification, with recovery rates ranging from 97.53% to 99.82%. These results confirm the method's high accuracy, outstanding linearity, and reliability for the quantification of silybin in formulations.

The validated HPTLC method proved to be a reliable analytical tool for the quantification of silybin in various formulations, particularly those containing polymers. The method's strong linearity, precision, and accuracy align with the ICH guidelines, making it suitable for routine analysis in quality control laboratories. The use of the Box-Behnken design for method optimization highlights the importance of systematic experimentation in achieving robust analytical outcomes.