Quality by Design (QbD)-Based Development and Optimization of a Simple, Robust RP-HPLC Method for the Estimation of Methotrexate

Methotrexate (MTX) is most widely utilized drug for anticancer therapy, as well as in the treatment of autoimmune diseases like arthritis and psoriasis. However, its estimation in different dosage forms is still a challenge. Though, various analytical methods have been reported, but they are tedious, difficult to reproduce, and time consuming. USP method is only reliable for MTX estimation, but suffers from disadvantage of having high buffer concentration leading to column blockage. So there is need to develop a novel HPLC method to overcome this problem. A simple, fast, and robust HPLC analytical method was developed by employing quality by design (QbD) for the estimation of drug in different dosage forms. The reverse phase (RP)-HPLC method was successfully developed and validated according to International Conference of Harmonization (ICH) guidelines with respect to linearity, accuracy, precision, etc. Further, the method was applied for estimation of MTX in different dosage forms like tablet, injection, lipid nanocarriers, lipid polymer hybrid nanoparticles (LPHNPs), and gel. The good recoveries of MTX were obtained as more than 95% with RSD of 0.5-2% from 0.5 to 40 mu g/mL, all values were found to be within the acceptable range. The results showed that the developed RP-HPLC method could be successfully utilized for identification and quantification of MTX in any dosage forms, with high resolution, accuracy, and precision.