Arena Pharmaceuticals Inc. said Friday it expects to receive about $60 million before expenses from a direct public offering of stock to entities tied to the health investment firm Deerfield Management.

Arena, which is based in San Diego, said it will sell a total of about 8.9 million shares for $6.70 per share. The offering will close around Aug. 10.

The company will use $30 million of the proceeds to prepay a portion of loan principal due in July, 2012, under an existing agreement between Arena and Deerfield.