Compatibility of Chlorhexidine and CI 16035 (Allura Red) in Mouthwash

In a mouthwash formulation containing Chlorhexidine Gluconate (which is a cationic, or positively charged, ingredient), using a color like CI 16035 (Allura Red) is generally not recommended.

CI 16035, being a water-soluble synthetic dye, is typically anionic (negatively charged). When a cationic ingredient like Chlorhexidine is mixed with an anionic ingredient like CI 16035, they can interact due to their opposite charges. This interaction can lead to:

• Precipitation or cloudiness in the formulation.
• Reduced effectiveness of the Chlorhexidine.
• Color instability or fading.

Therefore, it is best to avoid combining cationic ingredients with anionic colors in the same formulation to maintain stability and efficacy.

If you need to color a Chlorhexidine-based mouthwash, you would need to find a colorant that is compatible with cationic ingredients, such as a non-ionic colorant, if available and approved for oral use.