JOURNAL OF COSMETIC SCIENCE 112 Table VI Results of Interday Validation for 16 UV Filters UV fi lters 10 ppm 25 ppm 40 ppm Area SD %RSD Area SD %RSD Area SD %RSD PABA 478.23 7.32 1.53 1234.03 17.15 1.39 1964.42 20.63 1.39 PBS 602.43 7.87 1.31 1551.95 14.72 0.95 2462.31 17.68 0.72 TDS 639.59 7.27 1.14 1643.15 15.29 0.93 2604.33 19.15 0.74 BZ-8 161.29 4.53 2.59 413.52 11.46 2.77 717.38 11.57 1.61 BZ-3 175.05 4.53 2.59 450.76 9.43 2.09 717.38 11.57 1.61 IMC 909.88 6.77 0.74 2334.45 18.91 0.81 3725.85 14.33 0.38 DT 262.57 10.14 3.86 677.07 19.36 2.86 1085.38 7.64 0.70 MBC 278.26 10.40 3.74 724.35 17.06 2.36 1171.21 11.18 0.95 OC 621.38 6.95 1.12 1594.98 16.71 1.05 2557.24 14.69 0.57 MA 101.12 4.34 4.29 262.90 6.98 2.65 408.82 6.17 1.51 ED-PABA 690.38 30.01 4.34 1827.87 85.40 4.67 2863.01 126.87 4.43 BMDM 415.32 5.62 1.35 1084.42 16.59 1.53 1732.05 25.50 1.47 EMC 512.11 8.04 1.57 1315.83 14.69 1.12 2086.57 14.18 0.68 DBT 550.55 11.44 2.08 1420.63 15.36 1.08 2253.72 12.29 0.55 EHT 583.17 8.66 1.49 1504.86 15.14 1.01 2389.47 17.85 0.75 MBBT 177.67 6.35 3.57 468.34 12.57 2.68 721.13 30.59 4.24 Table V Results of Intraday Validation for 16 UV Filters 10 ppm 25 ppm 40 ppm UV fi lters Area SD %RSD Area SD %RSD Area SD %RSD PABA 484.90 6.30 1.30 1240.70 15.98 1.29 1971.09 20.69 1.05 PBS 609.10 5.96 0.98 1558.61 13.33 0.86 2468.97 16.65 0.67 TDS 646.26 6.59 1.02 1649.81 13.77 0.83 2611.00 17.93 0.69 BZ-8 164.62 1.41 0.86 420.19 3.66 0.87 665.53 4.28 0.64 BZ-3 178.38 1.33 0.75 456.09 3.86 0.85 724.05 4.45 0.62 IMC 916.54 4.93 0.54 2341.11 13.27 0.57 3732.52 9.03 0.24 DT 269.24 1.62 0.60 687.07 2.61 0.38 1088.72 2.18 0.20 MBC 284.92 2.05 0.72 734.35 7.19 0.98 1177.87 8.83 0.75 OC 628.05 4.96 0.79 1601.65 15.02 0.94 2563.91 9.01 0.35 MA 99.12 0.96 0.97 259.56 2.68 1.03 412.15 1.99 0.48 ED-PABA 697.46 23.48 3.37 1764.53 43.68 2.48 2803.01 86.88 3.10 BMDM 421.99 8.07 1.91 1091.09 14.86 1.36 1738.72 25.32 1.46 EMC 518.77 4.14 0.80 1322.50 10.67 0.81 2093.24 11.23 0.54 DBT 557.22 1.82 0.33 1427.30 10.61 0.74 2260.39 11.48 0.51 EHT 589.83 4.20 0.71 1511.53 12.19 0.81 2396.14 18.80 0.78 MBBT 182.34 1.97 1.08 475.01 5.54 1.17 722.00 26.20 3.55 comparable photostability (7,17,19). This inconsistent fi nding might result from the poor solubility of MBBT in either the organic or aqueous phase (17). Although the mixture of stock solutions was stable at ambient conditions for a couple of days, the standard solution has to be freshly prepared when concentrations of UV fi lters in

MONITORING OF UV FILTERS BY HPLC 113 Table VII Results of Recovery (%) Study for 16 UV Filters Spiked into Cream and Lotion Matrixes Cream matrix Lotion matrix UV fi lters 15 ppm 20 ppm 25 ppm 15 ppm 20 ppm 25 ppm PABA 101.49 ± 7.75 98.14 ± 0.87 103.64 ± 0.65 106.32 ± 0.66 101.92 ± 0.77 100.97 ± 2.55 PBS 98.71 ± 1.96 103.04 ± 2.04 98.23 ± 2.18 99.07 ± 1.14 105.66 ± 0.20 96.25 ± 1.61 TDS 101.10 ± 7.85 97.35 ± 0.70 102.13 ± 0.73 105.57 ± 0.32 101.42 ± 0.50 100.68 ± 2.43 BZ-8 99.70 ± 7.61 96.52 ± 0.80 101.82 ± 0.59 105.24 ± 0.65 100.79 ± 0.69 99.95 ± 2.46 BZ-3 98.96 ± 7.69 95.96 ± 0.90 101.72 ± 0.61 104.34 ± 0.61 99.90 ± 0.73 99.08 ± 2.44 IMC 99.68 ± 7.68 96.62 ± 0.88 101.93 ± 0.58 103.79 ± 0.60 99.36 ± 0.75 98.73 ± 2.39 DT 96.47 ± 3.66 97.97 ± 2.80 97.10 ± 1.90 94.90 ± 0.54 97.35 ± 0.73 95.64 ± 0.29 MBC 101.69 ± 8.15 97.15 ± 0.88 104.00 ± 0.86 105.43 ± 0.78 99.16 ± 0.83 100.04 ± 2.61 OC 101.17 ± 7.73 97.82 ± 0.88 102.86 ± 0.59 105.28 ± 0.67 100.86 ± 0.61 100.22 ± 2.39 MA 101.80 ± 7.09 99.02 ± 0.69 104.23 ± 0.50 104.30 ± 0.59 100.06 ± 0.78 99.52 ± 2.27 ED-PABA 99.07 ± 7.76 95.88 ± 0.90 100.79 ± 0.59 102.75 ± 0.41 98.08 ± 0.81 97.55 ± 2.33 BMDM 97.95 ± 7.53 94.98 ± 0.73 99.47 ± 0.50 100.82 ± 0.35 96.70 ± 0.76 95.03 ± 2.27 EMC 98.69 ± 7.68 95.47 ± 0.77 100.50 ± 0.60 102.04 ± 0.52 97.41 ± 0.75 96.81 ± 2.40 DBT 100.56 ± 7.79 97.62 ± 0.70 102.07 ± 0.66 104.60 ± 0.48 100.13 ± 0.73 99.45 ± 2.37 EHT 100.63 ± 1.47 104.94 ± 2.70 96.74 ± 0.51 98.39 ± 0.83 101.01 ± 1.35 95.67 ± 2.30 MBBT 108.09 ± 4.10 116.54 ± 7.89 114.42 ± 5.47 109.99 ± 1.31 116.27 ± 0.33 116.21 ± 0.45 Table VIII Repeatability for UV Filters Spiked into Cream and Lotion Matrixes Cream matrix Lotion matrix 15 ppm 20 ppm 25 ppm 15 ppm 20 ppm 25 ppm Area SD Area SD Area SD Area SD Area SD Area SD DT 286.12 0.30 387.50 0.61 476.42 0.15 274.78 0.30 380.18 0.20 464.21 0.48 MBC 466.10 0.37 572.61 0.93 772.14 1.32 458.43 0.72 587.15 0.80 748.21 0.63 MA 97.68 0.22 123.00 0.46 162.51 0.35 95.33 0.24 124.40 0.14 156.05 0.39 BZ-3 252.85 0.19 317.29 0.55 421.10 0.67 254.42 0.24 330.71 0.34 413.66 0.34 BZ-8 222.37 0.14 278.32 0.17 368.95 0.21 224.06 0.17 291.35 0.43 364.42 0.23 BMDD 742.39 0.41 934.14 1.05 1232.23 2.36 726.61 1.15 953.81 1.43 1185.67 1.48 EHT 855.65 0.96 1201.83 2.73 1399.76 1.97 828.84 0.95 1157.96 2.45 1411.88 1.67 OC 199.36 0.06 248.77 0.39 328.31 0.31 197.43 0.18 257.65 1.27 321.96 0.14 ED-PABA 594.61 0.13 742.13 0.65 981.79 2.37 585.68 0.53 761.45 1.34 954.65 0.91 EMC 366.13 0.30 457.38 0.45 605.95 0.56 359.64 0.41 467.40 0.31 586.86 0.79 PABA 750.58 0.54 940.09 0.57 1246.49 0.56 750.68 0.68 978.19 1.21 1222.55 0.93 PBS 726.14 0.21 1003.63 0.66 1145.22 0.99 705.89 0.41 1008.05 0.98 1147.44 0.03 IMC 601.31 0.24 753.15 0.56 998.28 0.66 596.60 0.43 775.84 0.52 972.62 0.77 DBT 636.08 0.57 791.23 0.77 1047.98 0.58 632.48 0.62 825.07 0.68 1046.02 0.56 MBBT 895.84 0.89 1123.17 0.75 1478.59 1.05 885.72 0.57 1154.94 0.88 1457.26 0.82 TDS 278.22 0.79 402.67 0.67 488.45 1.07 276.65 1.07 388.13 1.22 478.60 0.67