Another developer is taking over Carl Dranoff's plan to build apartments and retail at the site of the long-defunct Royal Theater on South Street.

Robert Roskamp, best known as the backer of the Roskamp Institute, a medical-research center in Sarasota, Fla., purchased the 1524 South St. property from music mogul Kenny Gamble's Universal Cos. last month, Roskamp said in an interview Monday.

Roskamp said he intends to stick largely to that original proposal, although he plans for-sale townhouses along the Kater Street-facing side of the property, rather than apartments. He hopes to submit an application soon to the city for permission to demolish the theater, minus the facade.

The developer, who divides his time between Sarasota and Chester County, had largely focused on senior housing during his career, with projects including Freedom Village in Coatesville and the Inn at Sarasota Bay Club in Florida.  He said he currently dedicates much of his time to the Roskamp Institute, which investigates causes of and potential therapies for neuropsychiatric and neurodegenerative disorders, such as Alzheimer's.