How to fully dissolve 5–10 % Kojic Dipalmitate (KD) in an emulsion and prevent re-crystallization.
1. Remember: KD is lipophilic
Kojic Dipalmitate is practically insoluble in water but dissolves readily in many oils at 85–90 °C at 5–10 % and even higher.
Suitable carriers:
– Caprylic/Capric Triglyceride (MCT)
– Isopropyl Myristate (IPM)
– Squalane, Shea Butter, Jojoba Oil
– Non-polar esters such as C12-15 Alkyl Benzoate
2. Recommended 3-step protocol (lab to scale-up)
| Step | Key Points | Purpose |
| ① Pre-dissolve in oil | Heat chosen oil to 90 ± 2 °C, add KD, stir 600 rpm until completely clear (5–10 min). | Full dissolution, crystal lattice broken |
| ② Hot emulsification | Immediately pour the 90 °C oil phase into the 75–80 °C aqueous phase (containing emulsifier) and homogenize 3 min at 6000–8000 rpm. | Fine emulsion, prevents re-crystallization |
| ③ Controlled cooling | Continue gentle stirring 400 rpm. Add Giga White & Snow White below 45 °C; add fragrance/preservative below 40 °C. | Protect actives, avoid thermal degradation |
Note: KD begins to crystallize < ~65 °C; keep emulsification temperature ≥70 °C.
3. Extra tips
Emulsifier HLB: use HLB ≈ 8–10 (e.g., Olivem 1000, Tween 60/Span 60 blend) for better crystal encapsulation.
Co-solvent: if still worried, pre-dissolve KD 1:1 in IPM or Dicaprylyl Carbonate before adding to the oil phase.
Homogenization energy: 8000 rpm × 3 min in the lab; scale-up target 25–30 m/s tip speed.
Filtration: pass the finished emulsion through 100–150 mesh to remove any accidental micro-crystals.