3593. Ensulizole

Nomenclature

CAS number: 27503-81-7
2-Phenyl-1H-benzimidazole-5-sulfonic acid; phenylbenzimidazole sulfonic acid; Eusolex 232 (Merck KGaA); Neo Heliopan Hydro (Symrise); Parsol HS (DSM).
C13H10N2O3S; mol wt 274.30.
C 56.92%, H 3.67%, N 10.21%, O 17.50%, S 11.69%.

Description and references

UV-B filter in sunscreens and cosmetics. Synergistic increase in SPF occurs in combination with oil-soluble UV absorbers. Prepn: V. G. Sayapin et al., Khim. Geterotsikl. Soedin. 5, 681 (1970), C.A. 73, 45409p (1970). See also: U. Heywang et al., US 5473079 (1995 to Merck Patent GmbH). DNA photosensitization study: C. Stevenson, R. J. H. Davies, Chem. Res. Toxicol. 12, 38 (1999). Photochemical studies: J. J. Inbaraj et al., Photochem. Photobiol. 75, 107 (2002). Fluorometric determn in urine: M. T. Vidal et al., Talanta 59, 591 (2003). Complexation with cyclodextrins: S. Scalia et al., Eur. J. Pharm. Sci. 22, 241 (2004).

Chemical structure

Properties

mp 410° (dec). Absorption max (phosphate buffer, pH 7.4): 300 nm. Soly in water: ≈0.03%.

Derivative

Sodium salt.

Nomenclature

CAS number: 5997-53-5
C13H9N2NaO3S; mol wt 296.28.
C 52.70%, H 3.06%, N 9.46%, Na 7.76%, O 16.20%, S 10.82%.

Properties

Soly: water >30%; 1,2-propylene glycol >20%.

Therapeutic Category

Ultraviolet screen.

Keywords

Ultraviolet Screen