A formulation matrix can assist in achieving an optimal formulation by simultaneously investigating multiple parameters that may include pH, buffer composition, drug-substance concentration, salts, and excipients. The samples are formulated and stored at ideal and accelerated degradation conditions, and analyzed over time. Specific tests employed during the formulation matrix include electrophoresis, chromatography, spectroscopy, and visual examination to assess gross changes such as the presence of particles or precipitates.
A formulation matrix is ideally run as early as possible during development. A formulation matrix conducted during Phase I or earlier may uncover stability issues that may be addressed, through reformulation, before considerable resources are devoted to clinical or analytics development. However, due to financial limitations the formulation matrix may be performed as late as Phase II.