S. No Drug Wavelength (nm) Linearity range (mMole) Regression equation Correlation coefficient
1 Lef 243.6 0.01-.055 Y=0.457x -6*10-5 0.9987
Diclo 258.4 0.09-0.18 Y=0.244x -6*10-5 0.9986
2 Lef 246.1 0.01-0.055 Y=0.435x +0.0011 0.9987
Flur 258.2 0.06-0.15 Y=0.442x -0.008 0.999
3 Lef 248.1 0.01-0.055 Y=0.430x -0.003 0.9993
Ibu 231.4 0.01-0.08 Y=0.615x+-0.003 0.9926
Lef=leflunomide, Flur=flurbiprofen, Ibu=ibuprofen, Mef=mefanamic acid Diclo=diclofenac sodium
Table 5: Regression analysis of leflunomide and NSAIDs at pH 4 by first order derivative spectrophotometry.