InvaGen Pharmaceuticals Inc. will expand its Long Island operations with the purchase of 550 South Research Place, in Central Islip, for $14.5 million. The site will be the headquarters and production facility for its affiliate Ascent Pharmaceuticals.

The seller is Creativewear LLC, an affiliate of Creative Bath Products Inc., a bath products manufacturer.

Located on a 16-acre site, 550 South Research Place is a two-story, nearly 250,000-square-foot property off of Carleton Avenue and near the New York Institute of Technology Central Islip Campus.

InvaGen develops, manufactures, markets and distributes generic prescription pharmaceuticals. The company has three other locations, about 120,000 square feet, including its headquarters in Hauppauge.

New York state and local officials offered nearly $5.6 million in incentives to Ascent, including $3.8 million in tax abatements, savings and exemptions over the course of nine years from the Town of Islip Industrial Development Agency (IDA).

The pharmaceutical company will invest $20 million toward infrastructure upgrades and additional manufacturing capacity, including special labs and packaging facilities.

James E. Devine, a partner at Lazer Aptheker Rosella & Yedid in Melville, represented the seller.

Peter L. Curry, a partner at Farrell Fritz in Uniondale, represented the purchaser, and handled the straight lease with the Town of Islip IDA and the mortgage financing. Nicole S. Howard, an associate at Farrell Fritz, also assisted in the deal.

The straight lease will give the IDA title to the property while the company receives tax abatements. The agency eventually will sell the property back to InvaGen for $1.

Mark A. Cuthbertson, of the Law Offices of Mark A. Cuthbertson in Huntington, was agency counsel for the Town of Islip IDA.

William F. Weir, a partner at Nixon Peabody in Rochester, was bond counsel for the IDA.

The location at 550 South Research Place was a “smart fit” for Ascent Pharmaceuticals, said Thomas Attivissmo, a senior director at Greiner-Maltz of LI Co. Inc., in Plainview, who acted on behalf of the seller. Key sewer hookups, 28-foot ceilings, a second-floor production area and loading access were some of the main features. The property also has a 450-car parking facility.

Construction is under way, and InvaGen will install a significant amount of new equipment.

“Manufacturing will start once FDA approval is received for the production process,” Mr. Curry said.

“After approval Ascent promises to bring good, high-paying jobs that will give the community a huge boost,” said Ralph Perna, an executive managing director at Newmark Knight Frank in Melville, who handled the sale on behalf of the purchaser.

Governor Andrew Cuomo said in a press release last year that Ascent plans to create 350 new jobs in the next five years while retaining 330 current employees.

Ascent also has agreed to honor the short-term leases of four tenants that occupy about 65,000 square feet of the facility.

In addition to Mr. Perna, his son Richard Perna, an associate director at Newmark Knight Frank in Melville, handled the lease on behalf of the purchaser.

The Town of Islip IDA was internally served by executive director William G. Mannix.