Deodorant Roll-on Formulation Issues: Phase Separation and Rough Texture with Carbopol SF1 and Aluminum Zirconium Pentachlorohydrex GLY

The issues of phase separation and rough texture in your deodorant roll-on formulations, especially when using Aluminum Zirconium Pentachlorohydrex GLY with Carbopol SF1, arise due to incompatibility between key ingredients.

Cause of the Problem

1. Incompatibility of Electrolytes and Gelling Agents:
   • Aluminum Zirconium Pentachlorohydrex GLY is an aluminum salt, which acts as an electrolyte.
   • Carbopol SF1 (a carbomer-type polymer) is an anionic polymer used for gelling and thickening.
   • When an electrolyte is added to a carbomer gel system, the ions from the aluminum salt disrupt the polymer network. This causes the polymer to collapse, leading to a loss of viscosity, phase separation, and a rough, non-smooth texture. This problem will occur in both water-based and alcohol-based formulations.

Solutions and Recommendations

To resolve these issues and create a stable deodorant roll-on formulation, we recommend the following:

1. Switch to Electrolyte-Tolerant Thickeners:

   • Since Carbopol SF1 is not suitable for formulations containing aluminum salts, we recommend using alternative gelling agents that can better withstand electrolytes, such as:
     • Hydroxyethylcellulose (HEC): A cellulose-derived gelling agent that offers good gelling capabilities and a certain degree of electrolyte tolerance.
     • Xanthan Gum: A natural gum that provides viscosity and stability in systems with electrolytes, often used in combination with other thickeners for enhanced performance.
     • Acrylamide/Sodium Acryloyldimethyltaurate Copolymer (or similar inverse emulsion polymers): Synthetic polymers designed to tolerate electrolytes and create clear, stable gels.
     • Sclerotium Gum or Gellan Gum: Natural gums that provide good viscosity and stability in electrolyte-containing systems.
   • Additional Tip: You should experiment with these gelling agents individually or in combination in appropriate ratios to achieve your desired texture and viscosity.

2. Mixing Procedure:

   • Gelling Agent Preparation: Ensure the gelling agent is fully dispersed and hydrated to form a complete gel before adding other ingredients.
   • Adding Aluminum Zirconium Pentachlorohydrex GLY: Dissolve Aluminum Zirconium Pentachlorohydrex GLY separately in a portion of the water or alcohol (depending on your formula's base). Then, slowly add this solution to the prepared gel base with continuous and consistent stirring to ensure the best dispersion and minimize polymer shock.

3. pH Adjustment (If Necessary):

   • Aluminum salts can affect the pH of the formulation, which might impact the efficacy of certain gelling agents. If using an electrolyte-tolerant thickener, you should check and adjust the pH of your formulation to be within the optimal range for both the gelling agent and the active ingredient for maximum stability.

Conclusion

The primary issue is the incompatibility between Aluminum Zirconium Pentachlorohydrex GLY and Carbopol SF1. Switching to an electrolyte-tolerant gelling agent, such as HEC, Xanthan Gum, or Acrylamide/Sodium Acryloyldimethyltaurate Copolymer, along with adjusting the mixing procedure, will help resolve the phase separation and rough texture issues.