IR3535 Mosquito Repellent Lotion for Children: Formulation Guide

1) Recommended Phase and Temperature for Addition

Ethyl butylacetylaminopropionate (IR3535) is directly water-soluble (up to approximately 5%) and highly soluble in ethanol and propylene glycol. Therefore, it is recommended to add it to the Water Phase or during the Cool-down Phase after the emulsion has formed and the product temperature has decreased.

• Optimal Temperature: It should be added at a temperature not exceeding 40-45 degrees Celsius to maintain its efficacy and stability, as it is a substance that should be protected from sunlight and high heat.

2) Safe and Effective Dosage for Children Aged 3 and Above

• Recommended Range: For children aged 3 and above, the recommended concentration is 10-20%. This range provides good mosquito repellent efficacy with a high safety profile.
• Maximum Recommended Limit: It can be used up to 30%, but for young children, using a lower concentration that is still effective is preferable to minimize any potential irritation.

3) Optimal pH Range and Compatibility with Other Ingredients

• Optimal pH: IR3535 is generally stable in a slightly acidic to neutral pH range (approximately pH 5.0-7.0), which is also suitable for the skin.
• Compatibility:
  • Preservatives: Generally compatible with common cosmetic preservatives such as Phenoxyethanol, Caprylyl Glycol, Benzyl Alcohol, or organic acid preservatives.
  • Fragrances: Generally compatible, as IR3535 itself has no disturbing smell.
  • Emulsifiers: Compatible with most common non-ionic and anionic emulsifiers used in lotions.
• What to Avoid:
  • Avoid using in formulations with very acidic or very alkaline pH, which may affect the stability of the ingredient.
  • Avoid prolonged exposure to high temperatures.

4) Example Guide Formulation for Children's Mosquito Repellent Lotion (Formula Structure with Simplified Steps)

Formula Structure (Example)

A. Water Phase

• Distilled Water: 60-70%
• Glycerin: 3-5% (Humectant)
• Carbomer or Xanthan Gum: 0.2-0.5% (Thickener/Gelling Agent)
• Disodium EDTA: 0.1% (Chelating Agent)

B. Oil Phase

• Caprylic/Capric Triglyceride: 5-10% (Emollient/Light Oil)
• Isopropyl Myristate: 3-5% (Emollient/Light Oil)
• Glyceryl Stearate SE or Cetearyl Alcohol + Polysorbate 60: 3-5% (Emulsifier)

C. Cool-down Phase

• Ethyl butylacetylaminopropionate (IR3535): 10-20%
• Preservative (e.g., Phenoxyethanol): 0.5-1.0%
• Fragrance: 0.1-0.3% (Optional)
• pH Adjuster (e.g., Triethanolamine or NaOH 10% solution): As needed (to achieve pH 5.0-7.0)

Simplified Manufacturing Steps

1. Prepare Water Phase (A): Heat distilled water, add Disodium EDTA and Glycerin, stir to dissolve. Slowly sprinkle Carbomer or Xanthan Gum while stirring or mixing until a gel forms. Heat to approximately 70-75 degrees Celsius.
2. Prepare Oil Phase (B): In a separate container, combine all ingredients in the Oil Phase (B). Heat to approximately 70-75 degrees Celsius, stirring until the emulsifier is completely dissolved.
3. Combine Phases: Slowly pour the Oil Phase (B) into the Water Phase (A) while continuously stirring or mixing at medium speed until an emulsion is formed.
4. Cool Down: Continue mixing while allowing the lotion to cool down to approximately 40-45 degrees Celsius.
5. Add Cool-down Phase (C): Once the temperature has dropped, slowly add Ethyl butylacetylaminopropionate (IR3535), preservative, and fragrance (if used). Stir until well combined.
6. Adjust pH: Check the pH of the lotion. If necessary, gradually add the pH adjuster until the desired pH (5.0-7.0) is achieved.
7. Package: Once the lotion has completely cooled and has a uniform texture, it can be packaged.