PT  - JOURNAL ARTICLE
AU  - Tsuchiya, Masakazu
TI  - Factors Affecting Reduction of Reference Endotoxin Standard Activity Caused by Chelating Agent/Detergent Matrices: Kinetic Analysis of Low Endotoxin Recovery
AID  - 10.5731/pdajpst.2017.008086
DP  - 2017 Jan 01
TA  - PDA Journal of Pharmaceutical Science and Technology
PG  - pdajpst.2017.008086
4099  - http://journal.pda.org/content/early/2017/09/18/pdajpst.2017.008086.short
4100  - http://journal.pda.org/content/early/2017/09/18/pdajpst.2017.008086.full
AB  - Reduction of reference standard endotoxin (RSE) activity was kinetically analyzed under low endotoxin recovery (LER) conditions, and was considered as an apparent first-order reaction. Temperature, pH, and salt concentrations affected the rates of reduction of RSE activity. Temperature appeared to be the most important factor affecting LER. Components of LER matrices, such as citrate and polysorbate 20 showed similar LER effect at concentrations commonly used. Phosphate concentrations showed negative correlation against the half-life of RSE activity in solutions containing phosphate buffer and polysorbate 20. Activation energy for LER with naturally occurring endotoxin (NOE) was higher than that with RSE, and this explained one of the reasons for NOE resistance to LER. Lower temperature, lower pH, and a higher salt concentration are preferable to avoid LER in a hold-time study. This study provides useful data for anticipation of the severity of the LER effect and future hold-time studies in the biopharmaceutical field.