Time (min) At pH 4% Availability (mean ±  S.D) At pH 9% Availability(mean ±  S.D) Lef Flur Lef Flur 0 100.35 ± 0.98 99.99 ± 0.98 100.1 ± 0.42 100.28 ± 0.11 30 99.55 ± 0.51 98.45 ± 0.25 100.4 ± 0.51 100.1 ± 0.25 60* 99.79 ± 0.26 105.47 ± 0.50 100.3 ± 0.26 99.89 ± 0.51 90* 101.61 ± 0.61 109.58 ± 0.52 99.87 ± 0.61 98.78 ± 0.52 120* 98.00 ± 1.02 109.43 ± 0.40 99.99 ± 0.99 99.15 ± 0.45 150*+ 94.24 ± 1.54 108.97 ± 0.64 102.1 ± 1.08 100.15 ± 0.89 180**+ 100.55 ± 0.31 107.41 ± 1.01 103.75 ± 0.51 101.87 ± 0.49   Lef Ibu Lef Ibu 0 100.22 ± 0.98 100.17 ± 0.24 100.7 ± 0.71 100.33 ± 0.325 30 104.32 ± 0.46 103.97 ± 0.35 101.75 ± 0.778 101.23 ± 0.478 60 107.56 ± 0.45 107.08 ± 0.13 101.65 ± 0.212 101.42 ± 0.60 90* 108.54 ± 0.41 114.33 ± 0.91 101.2 ± 1.23 101.39 ± 0.55 120* 105.32 ± 0.32 107.54 ± 0.42 102.225 ± 0.38 100.65 ± 0.489 150**+ 105.92 ± 0.11 108.29 ± 0.53 101.95 ± 0.49 99.93 ± 0.98 180**+ 105.07 ± 0.178 117.87 ± 0.19 102.35 ± 0.65 98.93 ± 0.51   Lef Diclo Lef Diclo 0 100.7 ± 0.707 100.3 ± 0.21 101.04 ± 0.58 100.09 ± 0.98 30* 103.36 ± 0.51 98.85 ± 0.23 102.25 ± 0.31 100.52 ± 0.75 60**+ 110.41 ± 0.58 98.79 ± 0.29 103.25 ± 0.22 100.84 ± 0.23 90**+ 112.95 ± 0.19 96.76 ± 0.33 104.3 ± 0.54 101.14 ± 0.46 120**+ 111.19 ± 0.268 96.77 ± 0.403 106.6 ± 0.19 100.84 ± 0.15 150**++ 111.76 ± 0.23 96.91 ± 0.321 104.8 ± 0.412 101.69 ± 0.28 180**++ 108.05 ± 0.71 97.94 ± 0.46 105.86 ± 0.313 101.83 ± 0.42       Lef Mef 0 - - 100.15 ± 0.21 100.08 ± 0.268 30 - - 101.75 ± 0.35 101.82 ± 0.247 60 - - 100.65 ± 0.49 101.79 ± 0.49 90 - - 100.69 ± 0.43 100.69 ± 0.43 120 - - 100.42 ± 0.82 101.39 ± 0.19 150 - - 102.7 ± 0.65 101.73 ± 0.558 180* - - 102.7 ± 0.42 101.73 ± 0.38 Lef=leflunomide, Flur=flurbiprofen, Ibu=ibuprofen, Mef=mefanamic acid, Diclo=diclofenac sodium. * and ** indicates p< 0.05 (significant) and p< 0.005 (highly significant)at pH 4 while + and ++ indicates p< 0.05 (significant) and p< 0.005 (highly significant) interaction at pH 9

Table 7: Interaction study of leflunomide with NSAIDs by proposed UV method.