Alleged fraudster and self-proclaimed 'Pharma Bro' Martin Shkreli has been hit with a $2.5 million lawsuit for failing to pay a doctor who provided consulting services for one of his healthcare companies.

In documents exclusively seen by DailyMail.com, Shkreli is being pursued for the cash in a suit filed Wednesday by one Dr. Thomas P. Koestler over services he provided to Shkreli's company Retrophin.

Shkreli shot to notoriety after his pharmaceutical company Turing bought antiparasitic drug Daraprin then jacked up the price by 5,556 per cent to $750 per pill.

His unapologetic stance over the move earned him the title of the most hated man in America.

But Shkreli was hauled into court in December last year after he was alleged to have committed securities fraud.

Martin Shkreli, currently facing charges for fraud, is being hit with yet another lawsuit from a doctor who says he has not paid him for consulting services

Dr Thomas P. Koestler, left, says Shkreli owes him $2.5 million

It is alleged he illegally used stock from the biotechnology firm Retrophin Inc. to pay off debts related to his struggling hedge fund and repay angry investors.

He is being charged with seven counts of fraud for running what United States Attorney Robert L. Capers, of the Eastern District of New York, has called a Ponzi scheme.

Police claim he took $11million from Retrophin to pay back victims in an alleged scam.

Koestler - a PhD in Medicine and Pathology - is now set to add to those woes with his lawsuit, filed at the district court in south New York. He says he was supposed to receive shares in Retrophin in return for his services but that Shkreli never transferred them.

In August an arbitrator ruled that Koestler should receive 155,000 Retrophin shares at $15 each, worth a total of $2.3 million - plus interest and expenses.

But Shkreli has still not paid up.

Shkreli was hauled into court last year and is being charged with seven counts of fraud for running what prosecutors have called a Ponzi scheme

On Sunday Shkreli filmed himself in Manhattan trolling Hillary Clinton after she nearly collapsed at a 9/11 ceremony, shouting at her to drop out of the election and voicing his support for her rival Donald Trump

The alleged fraudster was released on a $5 million bond in December regarding the securities fraud charges, ahead of a 2017 court date for him and his co-defendant Evan Greebel, a former lawyer for Retrophin.

Shkreli founded Retrophin in 2011 and headed the company until 2014.

He found time to pay Hillary Clinton an unsolicited visit at her daughter Chelsea's Manhattan apartment on Sunday, after the candidate was rushed away from a 9/11 memorial service. It was later revealed she had pneumonia.