There is an urgent need to establish Quality target product profile (QTPP) for topical products and identify the Critical Quality Attributes (CQAs) to develop meaningful drug product specifications based on clinical performance and to ensure equivalent safety and efficacy to the Reference Listed Drug (RLD).Most semisolid preparations such as pharmaceutical/ cosmetic creams, ointments, lotions etc. display complex flow behaviour including breakdown on application of high shear, thixotropy and viscoelasticity which can be described by the methods used in measurement of these parameters. Most of the semisolid systems such as ointments, creams, pastes, and gels are viscoelastic in nature as they display both liquid and solid properties within the same material. In this project we aim to vary key formulation and manufacturing parameters to identify and define potential failure mode that effect a products performance. We will compare bioavailability using both finite (in use) and infinite dosing and use tools such as Atomic Force Microscopy (AFM), Confocal Raman and multiphoton microscopy to study the effects of excipients and formulation on in vitro and in vivo skin. Apart from BE we aim to define cosmetic equivalence (CE). Sensorial similarity/cosmetic equivalence will be defined as a critical quality attribute through this process.
This project addresses a key issue of importance to the FDA. Critical Quality Attributes (CQAs) of topical drug products, their identification and complete understanding by a formulator is critical to topical therapy. The FDA needs to understand how to relate critical quality of drug products to their in vitro performance and then to in vivo performance. This includes the properties of actives, non-active excipients and the interaction of the product with the skin. This project develops of a framework of methodically testing for product evaluation, encompassing materials testing including that for a finished product. Interactions between the product and the skin can be predicted by prior knowledge of the individual components of the system. Hence, understanding the individual role of each of the critical quality parameters will help to formulate for Quality By Deign (QBD) rather than to be governed by testing as in Quality By Testing (QBT).