Amphora Discovery, a drug developer focused on small molecule therapeutics, has raised $13 million in its third round of venture capital funding.

Investors in the round include new London-based firm 3i, plus returning backers MPM Capital, Venrock Associates, Arch Ventures, and Versant Ventures.

The funds will be used to move Amphora’s product candidates into clinical development and make several new hires this year, the company has said.

Amphora plans to keep the round open through the spring, with a potential of raising an additional $20 million for a total of $33 million

The company previously has raised $48 million, including a $23-million Series B round in December 2002. Investors were the same, with the addition of CW Group.

Based in Durham, Amphora was founded in 2001 and is developing four potential product candidates, including two for treating inflammation, one for cancer and one for Alzheimer’s disease. The company currently has about 60 employees.