(180d) An Integrated Methodology for Chemical Product Design: Application to Hair-and Skin-Care Emulsions
In particular industrial sectors such as the cosmetics one, there is a considerable amount of heuristic knowledge, namely regarding qualitative function of ingredients, their incompatibilities and positive synergies, as well as their impact on sensorial attributes, which is a critical aspect for product acceptance . This heuristic knowledge has been recently incorporated into a systematic CAMbD methodology  using mixed-integer optimization with logical constraints  and in this work is further developed for cosmetic emulsions. The method considers a list of available ingredients classified according to their main function (e.g., emollients, emulsifiers, rheology modifiers). Then, heuristics regarding ingredientsâ selection, their concentrations in final product, and the manufacturing procedures are formulated as logical conditions, and further translated into algebraic constraints. These constraints, together with other known restrictions (technical, toxicological and/or legal, etc.), define a reduced design space. The search in this space is guided by property models relating product composition to key physicochemical properties or sensorial attributes. The multi-objective function is composed of a weighted sum of Taguchi functions with a target value for each cost/performance requirement (e.g. softness, greasiness and thickness of the product, etc.), which could be adapted by the designer. Through integer cuts, the entire set of feasible solutions within the reduced design space or a subset of interest may be generated.
To illustrate the proposed methodology, two case studies of a rinse-off conditioner and a body lotion are presented. From an initial list of 24 emollients, 4 rheology modifiers and 8 emulsifiers, a set of alternative formulations and respective manufacturing procedures is listed. The first 5% of these resu-lting alternative formulations were produced and then analyzed using instrumental and sensorial methods. The predicted values of the performance were similar for most of the formulations, confirming the potential of this methodology to model emulsified products.
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