Zapata has been linked with a whole host of clubs across Europe including Queens Park Rangers during the summer, but Napoli were the first to agree a fee with Argentine side Estudiantes earlier this week.
De Laurentiis revealed that the young forward came through a medical after agreeing terms this morning, with an official announcement over the deal expected in the next 24 hours.
He told Radio Kiss Kiss: "They just called me from the Castel Volturno ground.
"Zapata passed his medical and is to all intents and purposes now our player."
Zapata is a regular for Colombia at youth level, but is yet to make his full international debut as the likes of Radamel Falcao and Jackson Martinez block his path into the senior squad.