The man known as "big pharma bro" congratulates the Sydney schoolboys who made a cheap reproduction of his company's drug.

The man who has been called the "poster boy for greedy drug company executives" and "the most hated man in the world", Martin Shkreli, has congratulated a group of Sydney schoolboys who say they made a drug that his company charges at US$750 (NZ$1061) a tablet.

The efforts of the Sydney Grammar School students should be recognised because the students were "proof that the 21st century economy will solve problems of human suffering through science and technology", Mr Shkreli, 33, said in a short video message posted on YouTube on Friday.

"We should congratulate these students for their interest in chemistry and all be excited about what is to come in the stem-focused 21st century," he said.

GETTY IMAGES Martin Shkreli at a US House of Representatives hearing on drug prices in February.

Soon after the story broke, people on Twitter had started peppering Shkreli with questions about the story.

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FAIRFAX A handful of Australian teens synthesise an expensive anti-malarial drug for about $2 a dose.

Shkreli's company gained the rights to Daraprim, an anti-parasitic medication listed by the World Health Organisation as essential, and soon after he raised the price from US$13.50 (NZ$19.1) to US$750 a dose.

Shkreli said the price rise was to extract money from insurance companies to fund research for better drugs. He says anybody in the US without insurance who needs the drug can get the drug for free.

Under the guidance of Dr Alice Williamson at the University of Sydney, some year 11 Sydney Grammar students made the drug for about $2 a dose.

@nedavanovac lol how is that showing anyone up? almost any drug can be made at small scale for a low price. glad it makes u feel good tho. — Martin Shkreli (@MartinShkreli) December 1, 2016

In explaining his motivation during the Sydney Grammar school project, student James Wood said: "I don't believe his justification for the price hike." James, 17, said he thought this seemed "a bit wishy-washy".

"He was clearly trying to justify something driven by the profit motive," James said.

Other Twitter users suggested to Shkreli the boys' work had 'destroyed' him.

He laughed off this tweet from Luke Gamon, an Australian post-doc studying in Copenhagen.

@Scottyt2Hottie yea uh anyone can make any drug it is pretty ez — Martin Shkreli (@MartinShkreli) December 1, 2016

Shkreli said that making the drug is easy, or rather "ez".

The founder of the Open Source Malaria Consortium at the University of Sydney, Associate Professor Matthew Todd, noticed one of Shkreli's tweets said "learning synthesis isn't innovation".

Associate Professor Todd said: "On one hand you have Shkreli who bought a known thing and raised the price.

"On the other you have school kids who have made this thing in their spare time with their teacher. They had to develop stuff and really work on it.

"You tell me which of those is innovative."

He congratulated the students. "It's very impressive work," he said.

In response to Shkreli's tweet that "anyone can make any drug it is pretty ez", Dr Williamson said: "Not just anyone can make this drug. You need training and facilities and equipment.

She then made the point: "If anyone can do it and it's so cheap, it highlights why it shouldn't be US$750 a dose."

Shkreli did not respond to an invitation to comment.