By Hanns-Christian Mahler and Satish K. Singh

Polysorbates (PS) (or surfactants in general) are commonly added to biopharmaceuticals as stabilizers against interface-mediated stresses. They are recognized as critical excipients by the industry as well as regulators. In the last few years, a number of studies have explored PS as raw material, its stability, and its impact on product quality including Borisov et al. (2011), Hewitt et al. (2011), Kishore et al. (2011 and 2011a), Labrenz, and Borisov et al. (2015).

 

At the 2015 AAPS National Biotechnology Conference (NBC), we organized the symposium How Stable Is the Stabilizer? Polysorbate Degradation and Impact on Biopharmaceuticals where we explored (novel) analytical aspects as well as stability and degradation of polysorbates. As a follow-up, we want to discuss control strategies for this critical excipient both as raw material as well as in product formulations. New analytical methods enable detailed characterization of the raw material, beyond the compendial requirements. Methods to analyze polysorbates in products have also improved, although recovery in high concentration products can be challenging. The importance of this excipient, coupled with the heterogeneity of the raw material, the relatively low concentrations at which it is used, and the complexity of the degradation pathways and the degradation products has led to a resurgence of interest in all questions related to the use of polysorbates in biotherapeutics.