Evaluation of Emulsion Stability and Skin Healing Efficacy of Topical Formulations Containing Viable Lacticaseibacillus rhamnosus GG

Live microorganisms such as probiotics play a key role in maintaining skin barrier function by helping to balance the microbiome. Functionally, preparing probiotic skincare products is challenging because live cultures can be unstable in conventional packaging. This study aimed to formulate and evaluate emulsions containing Lacticaseibacillus rhamnosus GG (LGG), focusing on its viability, stability, and bioactivity. Emulsions were prepared using either live LGG strains or spray-dried microencapsulated LGG, and grouped into control bases, pH-adjusted, and preservative-added formulations. All formulations were assessed for LGG viability, appearance, pH, and viscosity. The favorable characteristic formula was further selected by microbial contamination test, antioxidant activity, ability to promote skin fibroblast proliferation, and wound healing efficacy. The results showed that the spray drying technique gives a 78.02% process yield with 96.52% LGG survival. The results from the viability test suggest that microencapsulation can support LGG survival; however, it did not improve viability in emulsion, likely due to potential nutrient effects from the wall material during storage. Further studies revealed that the LGG-loaded emulsions formulated with a pH-adjusted (F6) and a preservative-added (F9) formulation were promising. Among all formulations, the pH-adjusted emulsion containing live LGG (F6) demonstrated the highest stability, retained viability, and was free from microbial contamination. This formulation exhibits antioxidant activity, promotes fibroblast proliferation and migration, and facilitates wound repair. This finding suggests that a live LGG-loaded emulsion with optimized pH may apply for topical applications targeting skin wound healing.