IMPACT OF SAMPLE PREPARATION ON RESIDUAL MOISTURE ANALYSES FOR A LYOPHILIZED PROTEIN FORMULATION

This study compares residual moisture data obtained by thermogravimetr ic (TG) and Karl Fischer (KF) analyses of freeze-dried recombinant Des modus rotundus salivary plasminogen activator (DSPA) and the protein f ree placebo. Significant changes in water content were observed depend ing on the sample type as well as the relative humidity of the exposur e environment prior to analysis. The TG and KF analyses gave identical results only when the samples were handled identically. The method of choice for the determination of the true total moisture content of th ese samples is the KF analysis since it can be performed without any o pportunity for water exchange with the environment.