Cell cultures in the investigation of thiazide phototoxicity

The NHIK 3025 cell line (Norsk Hydro Institutt for Kreftforskning), a human in situ carcinoma of the cervix cell line, was used to investigate the thiazides bemetizide, bendroflumethiazide, benzylhydrochlorothiazide, bumetanide, butizide, chlortalidone, furosemide, hydrochlorothiazide, hydroflumethiazide, indapamide, piretanide, polythiazide, trichlormethiazide and xipamide for their potential phototoxic properties. Cell death following UVA irradiation and dependent on test substance concentration was observed in the presence of all the tested substances except chlortalidone, furosemide, indapamide and xipamide. Bendroflumethiazide was phototoxic at concentrations of 0.05 mM and higher; bemetizide, benzylhydrochlorothiazide, bumetanide and hydroflumethiazide were phototoxic at 0.25 mM and higher and butizide, hydrochlorothiazide, piretanide, polythiazide and trichlormethiazide were phototoxic at 0.5 mM and higher.