The United States is embroiled in a scandal that could cost pharmaceuticals companies millions and threaten their ability to sell their products in the United States.
The US Food and Drug Administration (FDA) says it has identified three new batches of fentanyl and another batch of heroin that are believed to be made by Chinese pharmaceutical giant AstraZeneca.
The FDA has issued a nationwide warning to pharmaceutical manufacturers to be vigilant in handling drug manufacturing and the sale of their drugs in the US.
The warning comes just days after AstraPharma filed for bankruptcy protection in the UK.
On Thursday, the FDA also said that the AstraDrugs company, which is owned by the Chinese state-owned company, has failed to meet a key health-related standard for its manufacturing process, leading the agency to issue a warning to other drugmakers.
The companies are also accused of failing to properly label fentanyl, an opioid analgesic with similar effects to morphine.
AstraMedics, AstraGardens and AstraX were accused of violating US law by manufacturing fentanyl with an inadequate level of potency.
The three new fentanyl batches are not the first time the Chinese pharmaceutical firm has been caught out selling drugs in America.
AstaPharma was also accused in 2016 of selling a powerful painkiller called Opana, which was banned by the FDA.
The FDA said it had identified two other batches of Opana.
According to Reuters, the AstaDrugs batches contain a higher dose of fentanyl, which the FDA said was more potent than morphine and was “more potent than many other prescription opioids.”
The FDA said AstraChemicals batches of heroin contain fentanyl in “significantly lower concentrations” than morphine, which has a half-life of less than a day.
The warning comes days after the FDA warned that Astra-Zeneca had failed to properly record its fentanyl manufacturing processes.
The drugmakers are facing numerous health problems related to their fentanyl production, according to Reuters.
The new batches have been detected in the bodies of people who had used the drugs and in tests that can determine if they are allergic to fentanyl.
The Associated Press contributed to this report.