Page 51 - Quality control of pharmaceuticals (07-PA 704)

Example (2):

Comment on the following data obtained from 9 experiments of 3 concentration
levels, each one repeated 3 times.

Range 75% 100% 125%
(a) (b) (c)

Sample No. 100.3 Percentage recovery 99.6
1 98.8 98.7 102.4
2 99.5 101.8 101.8
3 99.37 99.9 101.27

Mean 100.13

Grand mean: (Ʃ ai + Ʃbi + Ʃci) /9 = 100.26
Overall standard deviation S = 1.76
Overall coefficient of variation, CV% = (1.76/100.26) × 100 = 1.75%

Conclusion:
The results are accurate, since the synthetic mixtures contain 100.0% analyte and the
average mean = 100.26 and coefficient of variation less than 2%

2) PRECISION
• The precision of an analytical procedure describes the closeness or agreement

between a series of measurements obtained from multiple sampling of the