Understanding Ionic/Non-ionic Properties and Disodium EDTA in Formulations

Based on the information provided, here's a summary regarding ionic/non-ionic properties and the use of Disodium EDTA:

Ionic / Non-ionic Properties

• The terms ionic (anionic/cationic) and non-ionic primarily refer to the polarity of surfactants and emulsifiers. These are substances that reduce surface tension, such as detergents and emulsifying agents.
• Other general types of cosmetic ingredients typically do not fall under this specific classification in the same way.
• You can often determine the type by the ingredient's chemical name or class. For example:
  • Anionic (Negative Charge): Sodium Lauroyl Glutamate (AminoWash™), Sodium lauryl sulfate (SLS), Sodium Laureth sulfate (SLES).
  • Non-ionic (No Charge): Lauryl Glucoside, PEG-7 Glyceryl Cocoate (Coco Wash™).
  • Cationic (Positive Charge): Cetrimonium Chloride (CTAC). These are often used as conditioning agents rather than primary cleansers.
  • Amphoteric (Both Charges): Cocamidopropyl Betaine. These are generally mild.

Compatibility of Surfactants

• The main compatibility concern is mixing anionic (negative) and cationic (positive) surfactants, as they can react and form precipitates.
• Non-ionic and amphoteric surfactants are generally compatible with all types.
• Surfactants of the same charge (e.g., anionic + anionic) are compatible.

Mixing with Other Ingredients

• The information does not indicate that ingredients like natural oils, Vitamin E, Collagen, or CoQ10 are incompatible with ionic substances or surfactants. The compatibility issue discussed for surfactants is primarily between different types of surfactants based on their charge.

Disodium EDTA

• Disodium EDTA is used to chelate (bind with) unwanted metal ions present in water, not related to the ionic/non-ionic nature of surfactants or other ingredients themselves.
• These metal ions can cause instability in certain ingredients (like Vitamin C) or affect the clarity/stability of the formulation.
• Adding Disodium EDTA (typically around 0.1%) is a common practice in formulations, especially those using water, to improve stability and shelf life by neutralizing these ions.
• While generally compatible with most ingredients (>95% of formulas), there are specific exceptions where it should be avoided, such as with Copper Peptide, as it can bind to the copper and reduce the peptide's effectiveness.
• Therefore, including Disodium EDTA in a lotion formula is often beneficial for overall stability, unless you are using an ingredient known to be incompatible with chelating agents like EDTA.

In summary, the ionic/non-ionic classification is mainly for surfactants/emulsifiers and affects how different types of these ingredients can be mixed. Disodium EDTA's role is separate, focusing on managing metal ions in the water phase to enhance formula stability, and it is generally safe to include unless a specific ingredient in your formula is known to be sensitive to chelating agents.