A team of researchers at the Croatian pharmaceutical company Pliva, Gabrijela Kobrehel, Gorjana Radobolja-Lazarevski and Zrinka Tambura?ev led by Dr. Slobodan Ðokic, discovered azithromycin in 1980. It was patented in 1981, and was later found by Pfizer's scientists while going through patent documents. In 1986 Pliva and Pfizer signed a licensing agreement which gave Pfizer exclusive rights for the sale of azithromycin in Western Europe and the United States. Pliva brought their azithromycin on the market in Central and Eastern Europe under the brand name of Sumamed in 1988, Pfizer Zithromax in 1991, and Zentiva Azitrox. After several years, the US FDA approved AzaSite, an ophthalmic formulation of azithromycin, for the treatment of eye infections. AzaSite is currently marketed in the US by Inspire Pharmaceuticals.