Application of the Repeated Measures (Split‐Plot) Design to the Development of Processes for Drug Substances

Abstract A case study from the chemical and pharmaceutical industries is used to show the value of the repeated measures design in developing processes for drug substances. This article advocates the use of the repeated measures design in situations that commonly arise in the chemical and pharmaceutical industries when repeated measurements are taken on the same experimental unit, instead of the common practice of comparing only individual conditions, a procedure that is inappropriate in many cases. One of the most important advantages of applying the repeated measures design is the abundance of data that can be obtained by taking into account the entire response curve instead of only isolated individual points on it.