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. Author manuscript; available in PMC: 2008 Dec 15.
Published in final edited form as: J AOAC Int. 2006;89(1):22–34.

Table 3.

Precision data

Day 1 precision mg/100 g
Day 2 precision mg/100 g
Days 1 and 2 precision combined, mg/100 g
Test material identification/replicates Campesterol Stigmasterol beta-Sitosterol Campesterol Stigmasterol beta-Sitosterol Campesterol Stigmasterol beta-Sitosterol
Saw palmetto 45% powdered extract
1 34.9 16.8 114 34.8 17.4 105
2 35.2 16.7 116 34.5 16.9 101
3 34.5 16.8 115 35.2 17.5 103
4 36.7 17.2 116 34.7 17.6 102
5 34.8 16.5 115 35.3 17.4 103
6 34.6 16.7 114 34.7 16.8 102
 Mean 35.1 16.8 115 34.9 17.3 103 35.0 17.0 109
 SDa 0.813 0.232 0.894 0.314 0.333 1.37 0.602 0.372 6.53
 RSDr, %b 2.32 1.38 0.777 0.900 1.92 1.33 1.72 2.19 5.99
 Target RSDr lowb 3 4 3 3 4 3 3 4 3
 Target RSDr highc 4 5 4 4 5 4 4 5 4
 PRSDRc 6.60 7.37 5.52 6.60 7.33 5.61 6.60 7.35 5.56
 HorRatd 0.4 0.2 0.1 0.1 0.3 0.2 0.3 0.3 1.0
Alcohol-free saw palmetto
1 2.50 1.13 7.34 2.37 1.27 6.06
2 2.52 1.19 7.67 2.50 1.35 6.37
3 2.57 1.23 7.61 2.51 1.35 6.39
4 2.61 1.24 7.81 2.44 1.34 6.28
5 2.60 1.22 7.70 2.37 1.26 6.10
6 2.52 1.20 7.53 2.50 1.33 6.26
 Mean 2.55 1.20 7.61 2.45 1.32 6.24 2.50 1.26 6.93
 SD 0.0463 0.0397 0.162 0.0655 0.0408 0.137 0.0770 0.0713 0.728
 RSDr, % 1.82 3.31 2.13 2.67 3.09 2.20 3.08 5.66 10.5
 Target RSDr low 5 5 4 5 5 4 5 5 4
 Target RSDr high 7 7 6 7 7 6 7 7 6
 PRSDR 9.77 10.9 8.30 9.83 10.8 8.55 9.80 10.9 8.41
 HorRat 0.2 0.3 0.3 0.3 0.3 0.3 0.3 0.5 1.0
Liquid Herbal Extract: saw palmetto
1 1.98 1.34 7.17 1.85 1.47 7.50
2 2.04 1.34 7.37 1.83 1.52 7.84
3 1.98 1.35 7.23 1.82 1.57 8.00
4 1.95 1.33 7.11 1.88 1.44 7.77
5 1.97 1.40 7.33 1.87 1.50 7.80
6 2.29 1.54 7.78 1.84 1.49 7.90
 Mean 2.04 1.38 7.33 1.85 1.50 7.80 1.94 1.44 7.57
 SD 0.128 0.0807 0.240 0.0232 0.0445 0.169 0.131 0.0864 0.315
 RSDr, % 6.27 5.85 3.27 1.25 2.97 2.17 6.75 6.00 4.16
 Target RSDr low 5 5 4 5 5 4 5 5 4
 Target RSDr high 7 7 6 7 7 6 7 7 6
 PRSDR 10.1 10.7 8.34 10.3 10.6 8.26 10.2 10.6 8.30
 HorRat 0.6 0.5 0.4 0.1 0.3 0.03 0.7 0.6 0.5
Powdered saw palmetto berry
1 5.28 3.93 30.9 5.01 3.95 33.4
2 6.12 3.90 30.3 4.99 3.91 33.6
3 5.30 3.82 30.4 5.01 4.05 33.9
4 5.89 4.50 31.8 4.97 3.82 33.3
5 5.67 4.28 30.4 5.33 4.18 34.3
6 5.63 4.01 30.9 5.05 3.93 33.6
 Mean 5.65 4.07 30.8 5.06 3.97 33.7 5.35 4.02 32.2
 SD 0.328 0.262 0.564 0.135 0.125 0.366 0.389 0.203 1.58
 RSDr, % 5.81 6.44 1.83 2.67 3.15 1.09 7.27 5.05 4.91
 Target RSDr low 4 5 3 4 5 3 4 5 3
 Target RSDr high 6 6 4 6 6 4 6 6 4
 PRSDR 8.67 9.11 6.73 8.82 9.15 6.64 8.75 9.13 6.68
 HorRat 0.7 0.7 0.3 0.3 0.3 0.2 0.8 0.6 0.7
ProstActive Once Daily
1 38.3 19.9 117 35.6 18.0 101
2 35.3 18.5 109 35.0 18.1 100
3 36.7 19.9 115 36.6 19.5 103
4 34.8 18.6 108 36.3 19.2 102
5 39.6 22.6 119 36.2 19.3 102
6 35.3 18.2 109 36.0 19.3 100
 Mean 36.7 19.6 113 36.0 18.9 101 36.3 19.3 107
 SD 1.92 1.63 4.75 0.572 0.666 1.21 1.40 1.25 6.86
 RSDr, % 5.23 8.32 4.20 1.59 3.52 1.20 3.86 6.48 6.41
 Target RSDr low 3 4 3 3 4 3 3 4 3
 Target RSDr high 4 5 4 4 5 4 4 5 4
 PRSDR 6.55 7.20 5.53 6.57 7.24 5.63 6.56 7.21 5.58
 HorRat 0.8 1.0 0.8 0.2 0.5 0.2 0.6 0.9 1.0
ProstActive Plus saw palmetto combined with nettle root extract
1 31.8 10.4 129 34.4 9.42 117
2 31.5 9.25 128 36.0 10.2 119
3 32.0 10.1 130 35.6 10.1 119
4 31.3 9.17 121 34.5 9.90 116
5 30.3 9.37 119 36.5 10.5 120
6 32.3 10.5 126 34.1 10.0 115
 Mean 31.5 9.80 126 35.2 10.0 118 33.4 9.91 1.22
 SD 0.700 0.604 4.51 0.983 0.359 1.97 2.07 0.488 5.26
 RSDr, % 2.22 6.16 3.58 2.79 3.59 1.67 6.20 4.92 4.31
 Target RSDr low 3 4 3 3 4 3 3 4 3
 Target RSDr high 4 5 4 4 5 4 4 5 4
 PRSDR 6.70 7.99 5.44 6.59 7.96 5.50 6.64 7.97 5.47
 HorRat 0.3 0.8 0.7 0.4 0.5 0.3 0.9 0.6 0.8
Prostasan Prostrate Capsules
1 39.8 20.2 116 40.4 20.7 108
2 39.6 19.3 117 40.2 20.8 108
3 37.8 19.6 113 40.1 20.4 110
4 38.6 19.6 117 39.6 20.3 107
5 37.7 19.4 115 41.5 20.4 108
6 39.2 19.9 118 39.8 20.8 108
 Mean 38.8 19.7 116 40.3 20.6 108 39.5 20.1 112
 SD 0.900 0.333 1.79 0.668 0.225 0.983 1.08 0.542 4.32
 RSDr, % 2.32 1.69 1.54 1.66 1.09 0.910 2.73 2.7 3.86
 Target RSDr low 3 4 3 3 4 3 3 4 3
 Target RSDr high 4 5 4 4 5 4 4 5 4
 PRSDR 6.50 7.19 5.51 6.46 7.14 5.57 6.48 7.17 5.54
 HorRat 0.4 0.2 0.3 0.3 0.2 0.2 0.4 0.4 0.7
Pygeum and saw palmetto standardized herbal extracts
1 21.5 8.07 264 22.3 8.26 278
2 21.8 8.91 266 22.9 8.68 277
3 23.3 9.76 281 21.8 8.47 274
4 22.5 9.13 269 22.9 8.53 278
5 21.9 8.91 270 22.1 8.35 273
6 22.2 8.32 267 22.0 8.39 276
 Mean 22.2 8.85 270 22.3 8.45 276 22.3 8.65 273
 SD 0.639 0.600 6.02 0.468 0.148 2.10 0.538 0.467 5.48
 RSDr, % 2.88 6.78 2.23 2.10 1.75 0.761 2.41 5.40 2.01
 Target RSDr low 4 4 2 4 4 2 4 4 2
 Target RSDr high 5 5 3 5 5 3 5 5 3
 PRSDR 7.06 8.11 4.86 7.06 8.17 4.84 7.06 8.14 4.85
 HorRat 0.4 0.8 0.5 0.3 0.2 0.2 0.3 0.7 0.4
Saw palmetto pygeum lycopene complex tablets
1 112 100 268 114 102 269
2 113 101 268 129 115 300
3 114 101 268 115 102 271
4 116 103 274 117 103 274
5 109 98.1 263 121 107 280
6 118 104 279 125 112 293
 Mean 114 101 270 120 107 281 117 104 276
 SD 3.14 2.11 5.62 5.95 5.56 12.6 5.66 4.98 11.0
 RSDr, % 2.75 2.09 2.08 4.96 5.20 4.48 4.84 4.79 3.99
 Target RSDr low 3 3 2 3 3 2 3 3 2
 Target RSDr high 4 4 3 4 4 3 4 4 3
 PRSDR 5.53 5.63 4.86 5.48 5.58 4.83 5.51 5.60 4.84
 HorRat 0.5 0.4 0.4 0.9 0.9 0.9 0.9 0.9 0.8
Saw palmetto (Serenoa repens) dried fruit CO2 extracts
1 55.5 28.7 176 56.6 28.9 174
2 55.1 29.1 178 55.5 28.7 172
3 55.6 28.7 178 55.9 28.3 175
4 55.4 29.1 176 55.9 28.6 173
5 53.8 27.8 171 56.3 28.7 174
6 53.9 27.6 171 55.1 28.5 173
 Mean 54.9 28.5 175 55.9 28.6 174 55.4 28.6 1.74
 SD 0.818 0.648 3.22 0.538 0.204 1.05 0.842 0.462 2.42
 RSDr, % 1.49 2.27 1.84 0.962 0.713 0.603 1.52 1.62 1.39
 Target RSDr low 3 3 3 3 3 3 3 3 3
 Target RSDr high 4 5 3 4 5 3 4 5 3
 PRSDR 6.17 6.80 5.18 6.15 6.80 5.19 6.16 6.80 5.19
 HorRat 0.2 0.3 0.4 0.2 0.1 0.1 0.2 0.2 0.3
a

SD = Standard deviation.

b

RSDr = Intralaboratory relative standard deviation.

c

PRSDR = 2 C−0.15, where C is the mean concentration expressed as a mass fraction.

d

HorRat = RSD/PRSDR.