FORMULATION DEVELOPMENT
Compared to small molecules, biopharmaceutical drugs such as mAbs offer high specificity and potency, arising from their macromolecular structure. However, their structural complexity is the cause for challenges in formulation and delivery of mAb drugs (Mitragotri, Burke, & Langer, 2014). Formulability is defined as the suitability of a drug product to be formulated in a way appropriate for the desired route of administration (RoA) or delivery method. Its quality attributes include, but are not limited to, solubility, stability, viscosity and aggregation. Early formulability assessment is an important aspect in the development program of any new biopharmaceutical and is often not emphasized enough (Zurdo, 2013). In line with the QbD paradigm, the intended use of an antibody is considered in the target product profile (TPP), usually during early stages of drug development. By completing a TPP, considerations into RoA, dosage form, bioavailability and stability can be addressed in early stages (Figure 2). Ultimately, every single aspect of development that affects the efficacy, cost or simplicity of an antibody can become the difference between success and failure of a drug (Zurdo, 2013).