Parameters PCR PLS HPLC Reported HPLC method NIF ATN NIF ATN NIF ATN NIF ATN Mean 100.60 100.75 100.50 100.78 100.40 99.74 100.75 100.43 SD 0.96 0.42 0.85 1.07 0.36 0.81 0.42 0.51 N 5 5 5 5 5 5 5 5 Variance 0.92 0.18 0.72 1.14 0.12 0.65 0.18 0.26 t-test (2.306)a 0.33 0.52 0.59 0.65 1.39 1.58 - - F-test (6.388)b 5.11 4.58 4.04 4.38 1.32 2.54 - -

aThe values in parentheses are the corresponding tabulated values at P<0.05.

bHPLC method (C18 Agilent ODS column, (5μm, 250 mm×4.6mm, id. column), using methanol: acetonitrile: 0.025 M sodium dihydrogen phosphate 60:20:20 v/v/v and adjusted to pH 3 with phosphoric acid, flow rate 1 mL/ min, 235 nm)

Table 9: Statistical comparison of the results obtained by the proposed spectrophotometric and RP-HPLC methods and with the reported HPLC method [18] for the analysis of nifedipine and atenolol in Tenolate® SR capsules.