Formulation of semi solid dosage forms for topical application utilizing quality by design (QbD) approach

Over the last few decades, there have been advancements in our comprehension of the design and development of topical semisolid formulations; however, they still follow an empirical development. Our study focuses on building a framework for designing and developing topical semisolid products using 'Quality by Design' (QbD) approach.

A literature review was conducted to identify and list the factors related to the design and development of topical semi-solid dosage forms using Quality by Design approach. The information extracted from the relevant articles was used to build a QbD framework based on four main pillars: Define the Quality Target Product Profile (QTPP); identify Critical Quality Attributes (CQAs); identify Critical Material Attributes (CMAs) and Critical Process Parameters (CPPs); understand how CMAs and CPPs affect CQAs and establish a control strategy.

Some typical elements of the QTPP for topical products include dosage form, route of administration, shelf life, critical quality attributes of the final formulation. Critical material attributes such as characteristics of API (molecular weight, lipophilicity, solubility, metamorphosis events, and polymorphism), characteristics of excipients, and critical process parameters (temperature, heating and cooling rates, mixing speed, pumping speed, order of addition) are identified and explained for their impact on CQAs.

Proper characterization of the API and drug delivery system will increase the likelihood of developing a stable, pleasing, and tolerable topical formulation and minimize the risk of failure.