University of Pennsylvania Health System has purchased the 800 Walnut St. medical tower for the equivalent of $648 per square foot, a record for a Philadelphia office building.

Penn Medicine, as the hospital network is known, acquired the 12-story, 153,242-square-foot building from Wayne-based developer Liberty Property Trust for $99.25 million, Liberty said in a release on Tuesday.

The next-highest per-square-foot price for offices in Philadelphia was the $628 paid by Korea Investment Management Co. to acquire the U.S. headquarters building of GlaxoSmithKline at the Philadelphia Navy Yard, also from Liberty, according to records maintained by real estate services firm JLL.

Liberty developed the 800 Walnut St. medical office building in 2013 for Penn Medicine to occupy as a tenant. The building’s retail and parking garage sections are under separate ownership and not part of the deal with the health system.

The developer is in the process of selling off its remaining office holdings to focus on its increasingly profitable business as an industrial landlord.