Sustainable and stability-indicating RP-HPLC method for Tofacitinib: an integrated white analytical chemistry and A-QbD approach

A robust, eco-conserving reverse-phase high-performance liquid chromatography method was developed and optimized using Analytical Quality by Design principles. A two-factor, three-level central composite rotatable design was used to investigate significant methodological variables, including methanol concentration, flow rate, and column temperature. The suitability of each model was evaluated statistically, indicating that a quadratic model was most suitable for each response, with an Adj R²> 0.92. An optimized robust chromatographic method was obtained using Methanol:0.1% orthophosphoric acid buffer (60:40 v/v), a flow rate of 0.7mL min-1, a temperature of 30 °C, and a detection wavelength of 286 nm, with a Retention Time of 3.36 min and a Tailing Factor of 0.56. Validation was carried out in accordance with the International Conference on Harmonisation Q2 (R1) guidelines. On validation, excellent linearity was obtained with R²=0.9993 over the concentration range of 1–25 µg mL− 1. Accuracy was also demonstrated across a range of concentrations from 98.12 to 101.06%. Furthermore, the Relative Standard Deviation was discovered to be less than 1.5%. Moreover, LOD was determined to be 3.05 µg/mL, with a LOQ of 7.31 µg mL. Forced degradation studies under acidic, basic, oxidative, neutral, and photolytic conditions attested to the validity of the method as a stability-indicating one, as attested by Fourier transform infrared spectra, which characterized modifications in chemical structures reflecting specific pathways of decomposition. Sustainability assessment, through Analytical GREEnness (0.74), Complex Green Analytical Procedure Index, White Analytical Chemistry (0.81), with an E-factor of approximately 11,000, ascertained the environmental friendliness, as well as accordance with United Nations Sustainable Development Goals numbered 3, 12, and 13. Validation of the method was successful in quantifying Tofacitinib in a commercial preparation, with a mean analytical value of 99.42 ± 0.38%, thereby demonstrating high accuracy and reproducibility, as well as relevant utility as a pharmaceutical analytical tool. Among analytical techniques, reverse-phase high-performance liquid chromatography has been developed as a white, QbD-based, sustainability-attuned analytical tool that nicely balances high performance with environmental friendliness, making it highly useful as a pharmaceutical-quality-control tool.