Formulation, Scale-Up and Physicochemical Characterization of a Foaming Exfoliating Face and Body Scrub Containing 5% Alpha-Hydroxy Acid

Abstract

In this study, a foaming exfoliating face and body scrub formulation containing 5% lactic acid (alpha-hydroxy acid, AHA) was developed and its physicochemical, microbiological, and antimicrobial properties were evaluated at different production scales. The formulation contains lactic acid (5%, pH 3.5–4.0) as a chemical exfoliant, fine crystalline sucrose (30%) as a physical exfoliant, a combination of sodium cocoyl isethionate (SCI) and cocamidopropyl betaine as the surfactant system, glycerin (10%) as a humectant, yellow iron oxide (CI 77492) as a colorant, and lemon peel essential oil (Citrus Limon Peel Oil) as a fragrance ingredient. The formulation was successfully scaled up from laboratory scale (100 mL) to semi-industrial scale (10,000 mL) without any modification to the original composition. Physicochemical characterization revealed that pH values remained within the target range (3.885–3.997) across all production scales, homogeneous appearance and organoleptic properties were maintained, and no phase separation was observed following centrifugal testing. Microbiological quality assessment demonstrated that total aerobic mesophilic microorganism and yeast/mould counts were below 10 CFU/g, and the absence criterion was met for all specified pathogenic microorganisms. Challenge testing conducted in accordance with TS EN ISO 11930:2019 confirmed that the preservative system reduced all five standard challenge organisms below the detection limit by day 14, maintaining efficacy through day 28. Three-month stability evaluation confirmed that pH, color, odor, appearance, and microbiological safety parameters remained stable under all tested storage conditions. These findings demonstrate the physicochemical stability, microbiological safety, and suitability of the developed formulation for commercial cosmetic product development.