Understanding Percentage Usage and Mixing Method for Gluconolactone (PHA) in Water-Based Formulas
Question
I would like to ask about the usage percentage for Gluconolactone (Natural PHA).
The recommended usage is 0.75-2%. How should this be interpreted?
For example, if I make a 100ml water-based cosmetic formula with the following ingredients:
- Ingredient A: 5%
- Ingredient B: 1%
- Gluconolactone: 2%
- Water: 92 ml
What is the correct mixing method for the Gluconolactone?
Scenario 1:
- Ingredient A: 5 ml
- Ingredient B: 1 ml
- Dissolve 2 grams of Gluconolactone in 98 ml of water first, then take 2 ml of this solution to mix into the formula.
- Use 92 ml of water as before.
Scenario 2:
- Ingredient A: 5
- Ingredient B: 1
- Add 2 grams of Gluconolactone directly into the formula without dissolving in water first, since it's already a water-based formula.
- Should the water amount still be 92 ml, or should it be 94 ml to account for the powder weight?
Thank you very much. I look forward to your answer.
Answer
Understanding Percentages and Mixing Gluconolactone
In cosmetic formulations, percentages are typically calculated by weight (w/w), not volume (v/v), for accuracy. When a usage rate is given as a percentage, it refers to the percentage of the ingredient's weight relative to the total weight of the final product.
Let's look at your example of a 100ml formula, assuming you mean 100 grams for calculation purposes, which is standard practice:
- Total formula weight: 100 g
- Ingredient A: 5% of 100 g = 5 g
- Ingredient B: 1% of 100 g = 1 g
- Gluconolactone: 2% of 100 g = 2 g
- Water (or other base): 100 g - 5 g - 1 g - 2 g = 92 g
So, for a 100g batch, you would use 2g of Gluconolactone and 92g of water, along with 5g of A and 1g of B.
Regarding the mixing method for a powder ingredient like Gluconolactone:
The best method is to dissolve the powder in a portion of the water phase first before adding it to the main batch. This ensures that the powder is fully dissolved and evenly dispersed throughout the formula, preventing clumps or uneven concentration.
Your first proposed method of dissolving 2g in 98ml and then taking 2ml of that solution is incorrect for achieving a 2% concentration in the final product. Your second method of adding 2g directly to the main batch is closer in terms of ingredient amounts (using 92ml/g water), but adding powder directly can lead to dissolution issues.
Therefore, the recommended method is:
- Weigh out all your ingredients accurately based on the desired total weight (e.g., 100g).
- Take a portion of your total water amount (e.g., 10-20g) and add the 2g of Gluconolactone powder to it.
- Stir or mix until the Gluconolactone is completely dissolved. Note that Natural PHA (Gluconolactone) can take some time to dissolve fully in water.
- Combine this dissolved Gluconolactone solution with the remaining water and other water-soluble ingredients (A and B, assuming they are water-soluble).
- Mix the entire formula thoroughly.
This method ensures proper incorporation and distribution of the Gluconolactone in your water-based formula.
Relevant products containing Gluconolactone include Natural PHA and NaturePreserve™ Ultra.
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