Azeco Cosmeceuticals

Formulations

18. Question: We are developing a new formulation. We encountered an issue of solubility in water. Did an suggestion to use ethoxydiglycol. The condition improve a lot after the applicati on of ethoxydiglycol. However, there is still some crystal precipitation after 2 days. We wonder if there is anything we could do to improve the stability. Do you have any suggestions? Answer: We recommended to substitute at least part of the water with an organic solvent. You can use ethanol, propylen glycol, butylen gly col, starting from the substitution of a smal part (for example 5%), try until you will obtain a stable product. 19. Question: In a formulation we add Azelaic acid directly in the oil phase. The pH is between 4 and 5, is this the correct pH or should it be higher? Answer: The higher the pH, the higher the stability is. But considering the skin products cannot be alkaline, a pH between 5 and 6 will be better. 20. Question: Can a natural hydrocolloid (INCI: Carrageenan and Algin, pH 8-11), carbomer be used? Answer: The ones you have indicated have not resistance to electrolytes. So they are low performant in products very rich in Azelaic acid. Probably better carrageenan and Algin than carbomer. 21. Question: I premix my Azelaic acid (7%) in propanediol (15%) I get a white mixture, do I need to neutralize the acid with sodium hydroxide at pH 6-7? Answer: The addition of sodium hydroxide can only cause more precipitation in this solvent. Sodium azelate is more soluble in water but for sure less soluble than Azelaic acid in organic solvents. 22. Question: According to formula SC003, Is it possible to have a oil free serum at pH 4.5-5 with high bioavailability? Answer: Until the pH is neutral (up to 7) the bioavailability of Azelaic acid is good enough. The best choice is to stay at the lowest pH able to give the finished product enough stability. 23. Question: Does Azelaic acid have a higher bioavailability at pH 6-7 or 5 in the finished product? Answer: The bioavailability is higher for the acid form than for the sodium salt. So lower pH means higher availability, but for sure in aqueous media we need to maintain a compromise, using a pH not so low to improve the solubility in water of this active.

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