One day ago i took azithromycin for chlamydia when can i have potected sex ?

You could but: Condoms are very effective at preventing transmission of std that are caused by fluid like gonorrhea, chlamydia, trichomoniasis and hiv. It seems to me it would be more socially responsible until after you have been retested in a few weeks though before you put someone else at risk. You also should inform the current partner of the your recent infection so they have choice in their risk taking.