Danbury-based pharmaceutical developer Biodel has laid off 15 people, more than half of its workforce, after a crumbled partnership forced it to suspend a drug trial and evaluate options including a sale or a reverse merger, in which another company would acquire Biodel for its Nasdaq listing and cash reserves. It would amount to an ignominious end for Biodel, created in 2003 by onetime MannKind executive Dr. Solomon Steiner and others who set out initially to develop VIAject, an insulin treatment for diabetics designed to be absorbed into the blood faster than alternatives at the time, with a later version of the technology called Linjeta.