Mallinckrodt US LLC

Mallinckrodt US LLC is the main United States operating entity of Mallinckrodt plc, a specialty pharmaceutical company whose roots go back to a St. Louis chemical house founded in the 19th century. The U.S. LLC carries the group's American commercial and manufacturing footprint: specialty generic pharmaceuticals, branded specialty medicines, controlled-substance (narcotic and analgesic) products, and contrast media and other imaging agents used in diagnostic procedures. Its products are sold largely to hospitals, health systems, clinics, pharmacies and distributors rather than directly to consumers, which places the brand in the business-to-business side of the pharmaceutical market. The Mallinckrodt name is one of the oldest in American chemistry and pharmacy. The original Mallinckrodt Chemical Works became known for fine chemicals, radiopharmaceuticals and, later, pharmaceutical intermediates and analgesics. Over the twentieth century the business passed through several corporate owners, including Avon Products and Tyco International, before being separated as Covidien's pharmaceutical segment and then spun off as the independent, publicly traded Mallinckrodt plc in 2013. Mallinckrodt US LLC functions as the group's U.S. operating company within that structure, holding much of the American product portfolio and manufacturing base. Commercially, the brand is associated with specialty generics — particularly oral solid-dose and controlled-substance generics — as well as specialty brands in areas such as pain, neurology and autoimmune and rare disease therapies, and with nuclear medicine/contrast imaging products. The company has manufacturing and distribution operations in the United States, and its products reach patients mainly through hospitals, specialty pharmacies and wholesalers. Mallinckrodt has had a turbulent recent corporate history. The group faced heavy litigation over opioid marketing and over the pricing of Acthar Gel, and Mallinckrodt plc went through Chapter 11 bankruptcy proceedings, emerging and later re-entering restructuring. These events shaped the group's portfolio, debt and public reputation, and they are relevant context for the U.S. operating subsidiary, which is the entity through which much of the American business is conducted. The brand today positions itself as a specialty pharmaceutical manufacturer focused on complex, hard-to-manufacture medicines, controlled substances and imaging, rather than as a mass-market consumer health label.

The Mallinckrodt name began in 1867 with a chemical business founded in St. Louis, Missouri, by the Mallinckrodt family. Mallinckrodt Chemical Works grew into a producer of fine chemicals and, in the twentieth century, became an important supplier of radiopharmaceuticals and pharmaceutical intermediates, including work connected with early nuclear medicine and the Manhattan Project era's chemical processing. That scientific and manufacturing heritage gave the company a durable reputation in complex chemistry. During the later twentieth century the business was absorbed into larger corporations. It was owned by Avon Products and later became part of Tyco International's healthcare group, which was renamed Covidien. Within Covidien, Mallinckrodt operated as the pharmaceutical segment, making specialty generics, imaging agents and controlled-substance products. In 2013 Covidien spun the pharmaceutical business off as Mallinckrodt plc, an independent company listed on the New York Stock Exchange. The U.S. operating company, Mallinckrodt US LLC, became the vehicle for the group's American commercial, manufacturing and distribution activities. As an independent company, Mallinckrodt expanded through acquisitions, notably the 2014 acquisition of Questcor Pharmaceuticals, which brought Acthar Gel into the portfolio, and the 2015 acquisition of Ikaria, a critical-care company known for inhaled nitric oxide therapy. These deals increased the group's specialty-pharma footprint and its debt. The company also built a large specialty generics business, including controlled substances, and maintained imaging and nuclear medicine operations. From the mid-2010s the group was drawn into litigation over opioid products and over Acthar pricing, and it faced pressure from payers and regulators. Mallinckrodt plc filed for Chapter 11 bankruptcy protection in 2020, emerging in 2021 after restructuring that reduced debt and settled some opioid claims. A second restructuring followed later in the decade as the company continued to manage litigation and debt. Throughout these corporate changes, Mallinckrodt US LLC remained the principal U.S. operating entity through which the American pharmaceutical business was conducted. Today the brand is positioned as a specialty pharmaceutical manufacturer with a long chemical heritage, focused on complex and controlled-substance medicines and imaging products, and selling primarily into hospitals, clinics, pharmacies and wholesale channels.

• 2021

  Mallinckrodt plc emerges from Chapter 11 after restructuring.

• 2020

  Mallinckrodt plc files for Chapter 11 bankruptcy protection amid opioid and pricing litigation.

• 2015

  Mallinckrodt acquires Ikaria, a critical-care company known for inhaled nitric oxide therapy.

• 2014

  Mallinckrodt acquires Questcor Pharmaceuticals, adding Acthar Gel to its portfolio.

• 2013

  Covidien spins off its pharmaceutical segment as the independent, publicly traded Mallinckrodt plc.

• 1867

  Mallinckrodt chemical business founded in St. Louis, Missouri.

Specialty pharmaceutical manufacturer focused on complex generics, controlled substances and imaging products, sold mainly to hospitals, pharmacies and distributors.

• Acthar Gel (repository corticotropin injection)

• Specialty generic controlled substances

• Contrast media and imaging agents

• 2026

  Maine DEP sues Mallinckrodt US LLC over Orrington contamination cleanup

  The Maine Department of Environmental Protection filed a lawsuit in Penobscot Superior Court against Mallinckrodt US LLC, alleging that the company failed to properly clean up mercury contamination at a former chemical manufacturing plant in Orrington, Maine. The department is seeking injunctive relief and civil penalties. The case concerns the cleanup of contamination at the Orrington site.

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• 2026-08-25

  Maine DEP sues Mallinckrodt US LLC over Orrington contamination cleanup[1]Maine DEP sues Mallinckrodt US LLC over Orrington contamination cleanuppressherald.com

  Reported: 2026-08-25

  The Maine Department of Environmental Protection filed a lawsuit in Penobscot Superior Court against Mallinckrodt US LLC, alleging the company failed to properly clean up mercury contamination at a former chemical manufacturing plant in Orrington, Maine. The department is seeking injunctive relief and civil penalties.

1. 1Maine DEP sues Mallinckrodt US LLC over Orrington contamination cleanuppressherald.com