Design of experiments (DoE)

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A systematic approach to maximize information content

Formulation development must consider a large variety of different factors, from pH and ionic strength to the concentration of several potentially beneficial excipients. On top of that, these factors influence each other, making it extremely difficult to use a “one factor at a time” (OFAT) approach to find the optimal combination.

Design of experiments (DoE) is a systematic approach aiming to maximize information content from an experimental study, while keeping the number of experiments low. During formulation development, DoE is used to develop an experimental matrix that probes a limited number of input factor combinations simultaneously and then uses statistical analysis to allow scientists to choose the optimal formulation conditions. 

Although DoE does not replace scientific know-how and experience, the careful use of DoE allows large parameter spaces to be explored in a highly efficient way. DoE can also be a vital part of a Quality by Design (QbD) concept.

The steps of DoE during formulation development often follow a general pattern.

First, influencing variables (input factors) must be defined and the related responses (product or process results) need to be identified.

Second, the number of experimental settings must be selected, and the experimental design needs to be generated using software algorithms.

Third, an experimental work plan is drafted and reviewed. DoE is supported by dedicated software solutions, such as Design-Expert or MODDE, especially when it comes to the statistical analysis of the experimental results.

Contact our experts today and find out how a DoE approach can support your drug development program.