Martin Shkreli charged Retrophin for everything from his Starbucks coffee to a casino trip, according to an accountant who reviewed the start-up's finances as it prepared to go public and described them as "chaotic".

Shkreli, who ran Retrophin from 2011 to 2014, put his sister on the company payroll, charged a $US4130 ($5303) trip to the Borgata casino in Atlantic City, New Jersey, on his corporate credit card, and gave himself a lump sum payment of $US575,000 identified as "compensation", accountant Corey Massella told federal jurors at Shkreli's criminal fraud trial in Brooklyn, New York.

The 34-year-old is best known for raising the price of Daraprim - a 62-year-old drug primarily used to treat newborns and HIV patients - from $US13.50 to $US750 a pill.

Federal prosecutors have alleged that for five years, Shkreli lied to investors in two hedge funds and biopharmaceutical company Retrophin, all of which he founded. Shkreli's angry defence of his actions on Twitter and Reddit earned him the nickname "Pharma Bro".