Quality by Design (QbD) Paradigm: An Integrated Multivariate Approach to Transdermal Patch System Development

: The International Council on Harmonization issued quality by design (QbD) guidelines, including Q8 (R2) pharmaceutical development, Q9 quality risk management, and Q10 pharmaceutical quality system, to ensure the quality of pharmaceutical products. For continual and consistent improvement of the quality of pharmaceutical drug products, QbD tools, such as risk assessment, design of experiment, and control strategy, are used, which can solve the narrow areas in product development. Transdermal patch systems (TPS) are gaining attention among scientists and are one of the strong-growing drug delivery systems in the market as a result of numerous benefits, including lowering the dosing frequency, adverse effects and invasiveness, avoiding pre-systemic metabolism, and better patient efficiency and compatibility. Transdermal patch systems are a likable dosage form when compared to other dosage forms. However, several challenges are faced in TPS product development which has hindered enormous products concerning the market status of TPS in comparison to the oral dosage forms. The implementation of the QbD concept was much focused on oral dosage forms. Additionally, the lack of understanding of the development of TPS leads to failure and withdrawal from markets. Therefore, to understand the QbD concepts of TPS, an attempt has been made to review the QbD approach for the development of TPS from the identification of the Quality Target Product Profile to the arrival of design space, which might help the formulator to navigate the sticky areas, in the TPS development.