Gel Formulation Base and Calculation for 1000g Batch

To create a stable gel that does not revert, selecting the appropriate gelling agent and following proper formulation techniques are key. Here is a general guideline for a simple gel formulation and how to calculate the amounts for a 1000g batch.

Common gelling agents include Carbomer, Xanthan Gum, and Hydroxyethyl Cellulose (HEC).

General Gel Formulation Example (using Carbomer)

Carbomer is a popular choice for clear gels but requires neutralization to thicken. Ensure you use a grade suitable for your needs, such as Carbomer 940 or Carbomer U21.

• Phase A (Water Phase):
  • Water: 95 - 98%
  • Gelling Agent (e.g., Carbomer 940 or Carbomer U21): 0.5 - 1.5% (adjust for desired viscosity)
  • Humectant (e.g., Glycerin): 1 - 5% (optional, for skin feel and stability)
• Phase B:
  • Preservative: 0.5 - 1% (essential)
• Phase C (Neutralization):
  • Neutralizer (e.g., Triethanolamine or 10% Sodium Hydroxide solution): Amount needed to reach desired pH (typically pH 6-7 for Carbomer 940, pH 5-11 for Carbomer U21)

Calculation Method for 1000g Batch

To calculate the amount of each ingredient for a 1000g batch, multiply the percentage of each ingredient by 1000g.

Example Calculation (using percentages from the general formula):

• Water: 97% -> 0.97 * 1000g = 970g
• Carbomer 940: 1% -> 0.01 * 1000g = 10g
• Glycerin: 1% -> 0.01 * 1000g = 10g
• Preservative: 0.5% -> 0.005 * 1000g = 5g
• Triethanolamine (Neutralizer): Amount needed to reach target pH (start with a small amount and add gradually, e.g., prepare a 10% solution and add dropwise while mixing until gel forms and pH is correct).

Total weight should sum to 1000g.

Basic Method (using Carbomer 940)

1. Weigh water into a container.
2. Slowly sprinkle Carbomer 940 powder onto the water surface while stirring until dispersed. Allow it to hydrate fully.
3. Add Glycerin (if used) and mix.
4. Add the Preservative and mix well.
5. Prepare a dilute solution of your Neutralizer (e.g., 10% Triethanolamine in water).
6. While stirring, slowly add the Neutralizer solution drop by drop. The mixture will thicken into a gel. Continue adding until the desired consistency and pH (6-7) are reached.
7. Mix thoroughly and check the final pH.

Alternative Gelling Agent: Xanthan Gum

Xanthan Gum is another option that is generally easier to use and more tolerant of electrolytes than Carbomer. It does not require neutralization to form a gel.

Basic Method (using Xanthan Gum):

1. Weigh water into a container.
2. If using Glycerin, you can pre-mix Xanthan Gum with Glycerin to help it disperse better.
3. Add Xanthan Gum (or the Xanthan Gum/Glycerin mixture) to the water while stirring or blending at high speed until fully dissolved and a gel forms.
4. Add the Preservative and mix well.
5. Check the final pH.

Factors for Gel Stability (Preventing Reversion)

• Proper Hydration: Ensure the gelling agent is fully hydrated.
• Proper Neutralization: If using Carbomer, accurate neutralization to the correct pH is critical.
• Ingredient Compatibility: Ensure all ingredients are compatible with the gelling agent and each other.
• Preservation: Use an effective preservative system to prevent microbial growth.
• Storage: Store the finished product in appropriate conditions.

Always perform small-scale tests before producing a large batch.