(CNN) The former chairman and president of pharmaceutical giant Purdue Pharma was warned by a friend that the addictive nature of the powerful pain killing opioid OxyContin could make him the next Pablo Escobar, according to a recently obtained deposition.

The deposition, which took place in March and is part of the multidistrict litigation, saw Richard Sackler grilled over several aspects of the company's operation, from marketing of the drug, to his interaction with the sales team. The deposition showed that Sackler, who said his memory suffered from brain injuries stemming from a stroke, would at times say he could not remember.

In other questions, he would defend the company, saying that they did what they could at the time the drug was being marketed.

Sackler received the email from a friend, an anesthesiologist, who said he had a friend whose daughter was approached with the drug at school in January 2002.

"Somebody tried to sell her OxyContin in the halls of the school. I asked her what she shows about -- what she knew about OxyContin. I never discussed your company, et cetera, in her presence. Her reply: 'It's a designer drug, and sort of like heroin.' I hate to say this, but you could become the Pablo Escobar of the new millennium," wrote Sackler's friend in an email according to the deposition first obtained by the Wall Street Journal.

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