In drug development, designing a formulation for a drug product (a tablet, for example) calls for careful attention to both the physical and chemical properties of the active pharmaceutical ingredient (API or drug substance). It also requires awareness that certain physical attributes, such as particle size distribution of the drug substance, can change with processing conditions and changes in the synthesis route that is employed. The formulation, which includes all of the excipients used to make the tablet, ensures the active ingredient is released in such a way as to not only provide the best efficacy for the patient but also protect the drug substance. If the drug substance has unfavorable interactions with any of the excipients, it can have a negative effect on the shelf life and performance of the drug product and can potentially cause harm to the patient.
For these reasons, it is critical the experts creating the formulation are aware of any reactions that can occur between an API and a tablet’s excipients. This enables the correct choice of excipients, avoids unpleasant surprises at a later stage and allows the focus to remain upon the manufacturing scale-up of both the drug substance and the formulated product. So what can a pharmaceutical company do to recognize both unfavorable drug substance properties and incompatibility between an API and its formulation? Finding the answer to this question early allows a drug manufacturer to avoid potential risks to the patient as well as costly interruptions during development.