Formulating a 1kg Gel with Encapsulated Salicylic Acid (Timed-Release BHA)
Question
I am developing a 1kg gel formula using Encapsulated Salicylic Acid (BHA, Timed-Release). I calculated that for a 1kg batch, I would need approximately 66g of the BHA-Time Release ingredient to achieve 2% active BHA, which is the maximum allowed concentration.
My initial thought was to use Pro Polymer to create the gel texture. However, I understand now that Pro Polymer is not compatible with this ingredient.
Could you please provide guidance on:
- Confirming if my calculation of 66g for a 1kg formula is correct.
- Suggesting a suitable alternative gelling agent, such as Hydroxyethyl Cellulose.
- Providing a sample formula for 1kg using the correct ingredients.
- Outlining the mixing procedure for this formula, including any specific temperature requirements or mixing speeds.
Answer
BHA-Time Release Gel Formulation (1kg)
Based on your requirements and the product information, here is a guideline for a 1kg gel formula using Encapsulated Salicylic Acid (Timed-Release BHA) and Hydroxyethyl Cellulose.
Your calculation of 66g of Encapsulated Salicylic Acid for a 1kg formula is correct. This corresponds to 6.6%, which provides 2% active BHA, the maximum concentration allowed for over-the-counter products.
As noted in the product information and the staff's reply, Pro Polymer is not compatible with Encapsulated Salicylic Acid. To create a gel texture for this formula, you should use a non-ionic thickener like Hydroxyethyl Cellulose (HEC) or HPMC.
For Hydroxyethyl Cellulose, a starting concentration of 1% is recommended. You can adjust this percentage (typically between 0.5% and 3%) depending on the desired gel thickness.
Here is a sample formula for 1kg:
- Water (or other water-based ingredients): 924 g (92.4%)
- Encapsulated Salicylic Acid (Timed-Release BHA): 66 g (6.6%)
- Hydroxyethyl Cellulose: 10 g (1%)
Mixing Method:
- Heat the water phase to approximately 70°C.
- Slowly sprinkle the Hydroxyethyl Cellulose powder into the hot water while stirring continuously until it is completely dissolved and a gel forms.
- Allow the gel to cool down.
- Once cooled, gently add the Encapsulated Salicylic Acid. Mix thoroughly but avoid high-speed blending (keep below 1000 rpm) to prevent damaging the BHA capsules.
It is highly recommended to test a small batch (e.g., 30-50g) first to adjust the Hydroxyethyl Cellulose concentration to your preferred gel consistency before making the full 1kg batch.
Remember to store the finished product properly, away from sunlight and heat, with the cap tightly closed.
