Jillian Sackler, an arts philanthropist who struggled to preserve the reputation of her husband, Arthur, by distinguishing him from his two younger Sackler brothers and their descendants, whose aggressive marketing and false advertising on behalf of their pharmaceutical company, Purdue Pharma, triggered the opioid epidemic, died on May 20 in Manhattan. She was 84.

Her death, in a hospital, was from esophageal cancer, said Miguel Benavides, her health proxy.

Dr. Arthur Sackler, a psychiatrist and researcher who became a pioneer in medical marketing, bought Purdue Frederick, originally based in New York City, in the 1950s and gave each of his brothers a one-third share. They incorporated the company as Purdue Pharma in 1991. (Its headquarters are now in Stamford, Conn.)

Dr. Sackler died in 1987 — nine years before the opioid OxyContin was marketed by the company as a powerful painkiller. Shortly after his death, his estate sold his share of the company to his billionaire brothers, Raymond and Mortimer, for $22.4 million.

The company’s misleading advertising claim that OxyContin was nonaddictive prompted doctors to overprescribe it beginning in the 1990s. The proliferation of the medication ruined countless lives of people who became dependent on it.

In 2021, the company proposed a bankruptcy settlement in which members of the Sackler family agreed to pay $4.2 billion over nine years to resolve civil claims related to the opioid crisis. In return, they sought immunity from future lawsuits.