At least a half-dozen potential buyers have contacted state casino regulators about purchasing the Tropicana Casino and Resort, and a sale could take place within weeks, the head of the state Casino Control Commission said last week. Linda Kassekert appeared at a news conference at the Tropicana with former state Supreme Court Justice Gary Stein, the interim trustee who’s overseeing the casino until a buyer can be found, and Tropicana President Mark Giannantonio, who will stay on to run its day-to-day operations until the sale.