San Diego-based Zogenix, the developer of delivery systems for administering pain medication, is planning a follow on offering of its stock. According to an S-1 filed by the firm today, it is selling 12M shares of its common stock, and is looking to raise as much as $47.47M in its offering. Zogenix is listed on the Nasdaq Global Market as ZGNX. The new financing effort is being run by Leerink Swann, Wells Fargo Securities, Stifle Nicolaus Weisel, William Blair & Company, and Oppenheimer & Co. The new offering comes about 10 months after Zogenix had its IPO in November of 2010.