Tempo Pharmaceuticals, a Cambridge, Mass., developer of new-drug formulations, raised $12.1 million in a first funding round. The company, which touts itself as a “nanopharmaceutical” maker, aims to improve the safety and effectiveness of existing drugs using engineered nanoparticles designed to home in on particular organs or tissues, then release two or more drugs in sequence. Tempo initially plans to focus on cancer.

Venrock and Polaris Venture Partners led the round, joined by Lux Capital and William Rastetter, former chairman of Biogen Idec. The company’s release is here; VentureWire has more here (subscription required).