CAS 27503-81-7
AAKO name AakoSun PBSA
EC 248-502-0

Product description

AakoSun PBSA is better known as Phenylbenzimidazole Sulfonic Acid. It is a water-soluble sun filter that offers protection against UV-B and short range UV-A radiation. The free acid is poorly soluble in water, so it is only used as it’s soluble salts. When combined with oil-soluble UV filters such as AakoSun AVB, AakoSun TiO2 or AakoSun ZnO it offers much better protection against UV-A rays, which is a significant cause of skin cancer.

Approved for the use in sun care preparations in many countries worldwide.

  • In America max. 4% and in Europe max 8%.

Phenylbenzimidazole Sulfonic Acid is also known under the names Ensulizole and 2-Phenyl-1H-benzimidazole-5-sulphonic acid.



  • Water-soluble, what makes it feel lighter on the skin.
  • Has the ability to absorb UV light over a wide range of wavelengths and convert it to less damaging infrared radiation (heat).
  • Its potency and protective qualities do not degrade in sun exposure. It also might decrease the degradation of other UV-B blocker in sunscreen formulations.


Chemical structure

Chemical structure of Phenylbenzimidazole Sulfonic Acid


Packaging & storage

AakoSun PBSA is available in the following packaging types:

  • Carton cardboard boxes of 20 kg
  • Plastic drum of 25 kg

Must been stored in closed container in dry, cool conditions. Has a minimum shelf life of 2 years under appropriate conditions of storage.



  • Cosmetics
  • Fragrance
  • Hair care
  • Skin care
  • Sunscreens