Acne Lotion (แป้งน้ำ) Formulation Guidance

Regarding your interest in creating an acne lotion (แป้งน้ำ) formula and the question about replacing Resorcinol:

As previously mentioned, traditional Resorcinol is not permitted in leave-on cosmetic products by regulatory bodies like the FDA. The product you initially linked, Activated Resorcinol (4-butylresorcinol), is also not the same ingredient and is used for skin whitening, not acne treatment.

To create an effective acne lotion that is compliant with cosmetic regulations, you can utilize other proven ingredients. Your formula already includes Salicylic Acid and Zinc Oxide, both of which are excellent choices for acne treatment. Salicylic Acid helps to exfoliate pores and reduce blockages, while Zinc Oxide has antibacterial and anti-inflammatory properties.

A common ingredient often used in acne formulations, sometimes alongside Salicylic Acid, is Sulfur. Sulfur has keratolytic properties (helping to shed dead skin cells) and is also antibacterial and antifungal. Based on the available ingredients, BioSulphur™ EQ (Water Soluble Sulfur) or Nano Sulfur (Colloidal Sulfur Dispersion) could be suitable options to consider adding to your formula to enhance its acne-fighting properties.

To achieve the characteristic "แป้งน้ำ" texture, which is a suspension where solid particles (like Zinc Oxide and Sulfur) are dispersed in a liquid, you will need a suspending agent. This ingredient helps to keep the solid particles from settling too quickly at the bottom. Examples of suspending agents include BYK 410 (Anti-Settling Additive), AnyGel™, or Aristoflex AVC. The choice and usage percentage will depend on the specific agent and the desired viscosity and stability.

Sample Formula Structure (50ml total volume)

Here is a sample structure for a 50ml acne lotion, incorporating suitable ingredients and a suspending agent. Note: Percentages are approximate and may need adjustment based on the specific raw materials used and desired consistency.

• Zinc Oxide: 7% (approx. 3.5g)
• Salicylic Acid: 1% (approx. 0.5g)
• Aloe Vera Extract: 2% (approx. 1g)
• Sulfur (e.g., BioSulphur EQ or Nano Sulfur): 5-10% (approx. 2.5g - 5g) - Let's use 5% for this example calculation (2.5g)
• Suspending Agent (e.g., BYK 410, AnyGel, or Aristoflex AVC): 0.5-2% (approx. 0.25g - 1g) - Let's use 1% for this example calculation (0.5g)
• Water: Balance to 100% (approx. 84%, or 42g)

Calculation for 50ml (assuming density close to water for simplicity, so 50ml ≈ 50g):

• Zinc Oxide: 7% of 50g = 3.5g
• Salicylic Acid: 1% of 50g = 0.5g
• Aloe Vera Extract: 2% of 50g = 1g
• Sulfur (5%): 5% of 50g = 2.5g
• Suspending Agent (1%): 1% of 50g = 0.5g
• Total of above: 3.5 + 0.5 + 1 + 2.5 + 0.5 = 8g
• Water: 50g (Total) - 8g (Other ingredients) = 42g

So, for a 50ml batch, you would need approximately 42g of water.

Remember to add a preservative to prevent microbial growth, as this formula contains a high percentage of water and natural extracts. The type and amount of preservative will depend on the specific product chosen.

This is a basic guideline. Creating a stable suspension requires careful selection of the suspending agent and proper mixing techniques. You may need to experiment with the percentages of the suspending agent and solid ingredients (Zinc Oxide, Sulfur) to achieve the desired consistency and stability.