Simple Estimation of Uncertainty in the Quantification of Cefazolin by HPLC and Bioassay

This work proposes a procedure to estimate the measurement uncertainty for the quantification of cefazolin by high-performance liquid chromatography (HPLC) and microbiological assay (bioassay). HPLC method was performed according to United States Pharmacopeia (USP) and bioassay according to Brazilian Pharmacopeia (FB). The quantification of cefazolin by high-performance liquid chromatography was assess through the calibration curve equation (Y=0.0199 X–0.0323). The HPLC uncertainty was estimated based on the error of the slope and the intercept (between 4.4% and 5.3%). The bioassay uncertainty was estimated based on the standard deviation of inhibition zones of samples and standards solutions (between 6.2 and 6.7%). The uncertainties for bioassay are expected to be higher those obtained by HPLC. Both HPLC method and bioassay estimated uncertainties are reasonable for the scope of each method.