Abstract The interaction of the novel antioxidant drug ebselen, 2-phenyl-1,2 benzisoselenazol-3 (2H)-one, with human serum albumin (HSA) was investigated by spectrophotometry. 6.7 mM, pH 7.4 of phosphate buffer containing 0.4 % (v / v) dimethylformamide (DMF) was used as the solvent. Various amounts of ebselen and HSA mixtures were used. Incubations of the mixtures were performed for 15 minutes at 25°C and 30 minutes at 37°C. An irregular change and the lack of an isobestic point in the final spectra of the mixtures indicated that the formation of mixed albumin selenodisulfides. It was also determined that the structures of the final products formed from the interactions of the drug and HSA, were depended on both drug and HSA concentrations. Özet Antioksidan özellikte yeni bir ilaç maddesi olan ebselen’in ( 2-phenyl-1,2 benzisoselenazol-3 (2H)-one) insan serum albümini (HSA) ile etkilesimi spektrofotometrik olarak incelendi. Çözücü olarak 0.4 % (v / v) dimetilformamid (DMF) içeren 6.7 mM, pH 7.4 fosfat tamponu ve farkli miktarlarda ebselen-HSA karisimlari kullanildi. Karisim inkübasyonlari 25°C de 15 dakika ve 37°C de 30 dakikada gerçeklestirildi. Sonuç spektrumlarindaki düzensiz bir degisim ve bu spektrumlarda izobestik bir noktanin bulunmayisi karisik albümin selenodisülfürlerin olustugunu göstermistir. Ayrica ebselen ile HSA etkilesimi sonucunda olusan ürün yapilarinin ilaç ve HSA’nin her ikisinin de konsantrasyonlarina bagli oldugu saptanmistir.

Keywords: Ebselen (PZ 51), human serum albumin, spectrophotometry