Developing generic versions of complex drug products presents a number of challenges as a result of the nature of their formulation or their route of delivery. In response to this, regulators, including the US FDA, have released product-specific guidance aimed at advising generics manufacturers on the approaches which may be applied to prove bioequivalence in vitro through the measurement of a complex drug product’s physicochemical properties.

In this webinar we will consider the regulatory guidance which is available for assessing the bioequivalence of topical formulations such as creams, ointments and gels. These products are considered complex formulations as it is the concentration of the drug and its rate of absorption at the site of action which define the drug’s bioavailability, rather than its concentration in systemic circulation. Product-specific guidance documents from the US FDA highlight the importance of physicochemical properties such as API particle size and crystal habit, along with the rheological properties of the formulation, in assessing drug product bioequivalence. We will consider how this guidance for bioequivalence studies can be followed and will also consider the additional insight which can be obtained through the application of physicochemical analysis techniques in order to aid prototype formulation development and optimization.