Replacing Synthetic Ingredients by Sustainable Natural Alternatives: A Case Study Using Topical O/W Emulsions.

With the increasing debate on sustainability, there is a strong market trend to formulate more sustainable products for topical application. Several studies emphasize the potential applications of natural, organic, or green chemistry-derived ingredients, but comparative studies between conventional ingredients and sustainable alternatives are lacking. This type of study is considered an excellent baseline and time-saving strategy for future studies. In addition, one of the main challenges of replacing ingredients by sustainable alternatives in topical vehicles is to maintain high-quality products. Thus, the main goal of this research study was to create a well-defined strategy supported by specific experimental data for the development of sustainable topical vehicles with high-quality standards. The study was designed to evaluate the effects of replacing conventional ingredients (e.g., hydrocarbons, silicones, and preservatives) by sustainable ones on the physical, chemical, and microbiological features of topical emulsions. Additionally, in vivo assessment studies were performed to evaluate the safety, biological efficacy, and sensorial aspects of the developed formulations. The results obtained showed that the replacement of ingredients by sustainable alternatives has an effective impact on the physicochemical and structural properties of the emulsions, mainly on their rheological behavior. However, using appropriate strategies for ingredient selection and rheological adjustment, it is possible to overcome some barriers created by the use of natural raw materials, thus developing appealing and high-quality sustainable topical vehicles.