Validation of an optimized method for determination of α1-antitrypsin activity

Abstract

Objective To validate an optimized method for determination of α1-antitrypsin (o1-AT) activity.Methods The chromogenic substrate method was used for determination of α1-AT activity.The previous established method was optimized by substitution of bovine trypsin for lyophilized normal human serum as reference standard.The accuracy and repeatability of the optimized method were validated,and effects of different substances on the optimized method were observed.Results When trypsin concentrations were in a range of 0.01-0.05 g/L,the optimized method showed a good linearity,and the correlation coefficient was more than 0.99.The optimized method had a good accuracy and repeatability.When 0.01,0.03 and 0.05 g/L trypsin were detected by the optimized method,recovery rates of trypsin were 99.33％,94.44％ and 92.67％,and the variable coefficients were 3.79％,1.66％ and 1.02％,respectively.Concentration changes of polyethylene glycol,sucrose,sodium citrate and human albumin in a certain range did not influence determination of α1-AT activity by the optimized method.Conclusion The optimized method for determination of α1-AT activity with bovine trypsin as reference standard can be used for the routine quality control in o1-AT preparation process. Key words: Alpha 1-antitrypsin; Trypsin; Chromogenic substrate method