Science
Mechanism of Action
As a non-ionic block copolymer surfactant, Poloxamer 338 reduces the surface tension of substances, enabling the formation of stable emulsions and aiding in the solubilization of other ingredients within a solvent system. When applied to hydrophobic surfaces, its structure allows the hydrophobic polypropylene oxide (PPO) blocks to anchor to the surface, extending hydrophilic polyethylene oxide (PEO) chains into the solution. This unique self-assembly mechanism can effectively diminish non-specific protein adsorption and bacterial adhesion by creating a hydrated, sterically hindered barrier on the surface.
Research
Clinical Evidence
Medium confidence0.5%
Key findings
- 01 At a 0.5% concentration, Poloxamer 338 demonstrated a statistically significant reduction in E. coli biofilm (90.10% ± 4.13% and 63.97% ± 8.59%) in an in vitro catheter model after 6 hours of treatment.
- 02 When adsorbed onto silicone catheters, Poloxamer 338 (5 mg/mL or 0.5%) reduced E. coli adhesion by approximately 85% (0.83 log10) and 78% (0.65 log10) under static conditions.
Transparency
Dusting Analysis
Poloxamer 338 is a functional ingredient primarily valued for its surfactant and emulsifying properties, not typically for active ingredient claims. It is not commonly 'dusted' in formulations.
The Formula
Formulation
Stability
Poloxamers are generally stable materials. Their aqueous solutions maintain stability across a range of pH conditions, including in the presence of acids, alkalis, and various metal ions. However, it's important to note that aqueous solutions of poloxamers can be susceptible to mold growth, necessitating appropriate preservative systems.
Conflicts
- While not specific to Poloxamer 338, other poloxamers (e.g., Poloxamer 192) have shown incompatibilities with phenols and parabens, depending on the relative concentrations. This suggests a potential for class-wide interactions that formulators should consider.
Safety
Safety Profile
The CIR Expert Panel has deemed Poloxamer 338 safe for use in cosmetics. While specific reproductive and developmental toxicity data were not available, its high molecular weight and solubility predict low skin penetration. It is recognized by the FDA as an indirect food additive for sanitizing solutions, indicating a low toxicological profile. It is generally considered non-toxic and non-irritant.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Poloxamer 338 is a valuable and safe functional ingredient, essential for its versatile surfactant and emulsifying capabilities in a wide array of precision skincare and cosmetic formulations.
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References
Sources