Azeco Cosmeceuticals

Dosage of finished forms

40. Question: Is the action of Azelaic acid dosage dependent? And is transdermal transport also a factor? Answer: Both the factors are important: dosage and transdermal absorption. The action relates to the dosages, to have a product with only claims of antimicrobial action, to maintain clean the skin, low amounts can be added (about 3-5%). For claims relative to anti acne, anti rosacea or whitening action, the range increases to 10-15%. The use of good solvents of Azelaic acids (glycols) increases the transdermal absorption, as the preparation on creams based on liposomes or similar structure (organogel). 41. Question: What is the best recommended dosage of Azelaic acid for an anti acne formulation. And what would be the best formulating pH range? Answer: It is better to stay around 10% if possible. The best pH for stability issues is 5.5-6.5. 42. Question: What is the best recommended dosage of Azelaic acid for skin lightening and anti-dark spots formulation. What would be the best formulating pH range?

Answer: For skin lightening 10% to 15% is recommended and pH between 5.5 and 6.5. 43. Question: Is the pH for a cream lower than for a serum?

Answer: In theory not, in general both of them must have a pH as much as possible (depending on product stability) similar to the skin pH: about 5.5. Lower pH are some times possible for peel to increase the action of the active. But please consider that if a serum is mainly based on organic phase (glycols, silicon based fluids, ethanol, etc.) the measurement of pH some times is not possible and if in any case measured, the registered values could be not reliable. 44. Question: What percentage of Azelaic is recommended for professional use versus home care use?

Answer: For home use treatments it starts at 8% and professional use is higher about 10% to 15%.

Mussenberg 1 • 6049 GZ Herten • The Netherlands

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