Simple Simultaneous Assay of Methotrexate and Non-Steroidal Anti-Inflammatory Drugs by HPLC

The combination of methotrexate (MTX) and non-steroidal anti-inflammatory drugs (NSAIDs), which is frequently used for rheumatoid arthritis (RA) treatment, courses of adverse events. To prevent these, simultaneous monitoring of these compounds is available. Therefore, we developed a new method for MTX and NSAIDs such as loxoprofen (LP), meloxicam (MX), lornoxicam (LX), diclofenac (DF) and celecoxib (CX) determination using HPLC with simple pretreatment of human serum sample. The separation of MTX and 5 NSAIDs was performed on C6-Phenyl column with gradient elution using 10 mmol/L ammonium acetate aqueous solution and methanol, and achieved within 25 min of analytical runtime. Calibration curves using standards showed good linearity ( r 2 >0.9998) in the range of 0.02-500 pmol/10 μL injection for MTX, 10-500 pmol for LP, 0.2-500 pmol for MX and DF, 0.05-500 pmol for LX and 2-500 pmol for CX. The detection limits of the proposed method were at least less than 96.0 fmol, and repeatability was less than 4.62 RSD%. In addition, acceptable precision of less than 10.19 RSD% and recovery of more than 54.4% of the method were obtained because the peaks of MTX and NSAIDs could be well-separated from those of interferings in serum. the method be useful to avoid occurring adverse events, and confirm the curative effect of MTX and NSAIDs.