Addressing Excipient Variability in Formulation Design and Drug Development

Variability of excipient attributes has often been characterized into source-to-source variability or lot-to-lot variability from the same source or vendor, also termed intersource variability or interlot variability, respectively. The former is controlled much readily by establishing and controlling the source of raw materials. The latter is often difficult to identify, understand, and control. This chapter primarily focuses on the interlot variability of excipients from the same grade and source or supplier and provides a comprehensive framework of approaches that can be proactively adopted to understand and investigate lot-to-lot variability encountered in excipients, with an intent to building a robust drug product with a sound control strategy around critical material attributes.