Tepha, a Lexington, MA-based provider of polymers for medical applications, has raised $3 million of a proposed $7.4 million round of equity financing, according to an SEC filing. Company CEO Simon Williams was not immediately available for comment this morning. The filing does not list the firm’s investors in this funding. The company’s website says that some of its previous investors include Integra Ventures, Novartis Venture Fund, The Vertical Group, and Westfield Life Sciences Fund. Tepha is a spinoff of Cambridge, MA-based Metabolix (NASDAQ:MBLX), a maker of bio-plastics and other cleantech products.