Tranzyme, a clinical-stage biotech developing small molecule therapeutics to treat gastrointestinal disorders, filed on Friday with the SEC to raise up to $75 million in an initial public offering. The Durham, NC-based company, which was founded in 1998 and booked $1 million in licensing and royalty revenue last year, plans to list on the NASDAQ under the symbol TZYM. Citi is the lead underwriter on the deal, for which pricing terms and timing were not disclosed.