Two pharmaceuticals companies asked a federal court to block Arkansas from using their drugs for upcoming executions, claiming that doing so would violate contractual controls and create a public health risk, court documents showed.

Arkansas, which has not had an execution in 12 years, plans to kill seven inmates over 11 days from April 17, including three pairs of dual executions. No state has ever executed as many inmates in as short a period since the U.S. Supreme Court reinstated the death penalty in 1976.

The inmates scheduled to die by lethal injection this month have launched a series of motions in federal court in Little Rock to block the proceedings. They argue that the rush to the death chamber increases the chances of a botched execution.

Fresenius Kabi USA and West-Ward Pharmaceuticals Corp. filed a brief on Thursday asking a federal court in Arkansas to take into consideration that the use of their drugs during a lethal injection "violates contractual supply-chain controls" they have it place, according to an online court document.

The companies sell their drugs only to wholesalers and distributors that agree to resell only to acute-care hospitals, clinics and healthcare facilities. They also instruct resellers not to sell or deliver their drugs to correctional facilities, according to the brief.

The companies also claim that use of their drugs as part of a lethal injection cocktail would create a public health risk by decreasing the supply of the medications and that the improper buying and selling of the drugs makes them unsafe.

"The use of the medicines in lethal injections runs counter to the manufacturers’ mission to save and enhance patients’ lives, and carries with it not only a public-health risk, but also reputational, fiscal, and legal risks," the companies wrote.

Republican Governor Asa Hutchinson has said the state must act quickly because the efficacy date for one of the chemicals in its lethal injection mix, the sedative midazolam, expires at the end of April.

Arkansas uses potassium chloride in combination with vecuronium bromide and midazolam. The latter drug is intended to render the inmate unconscious before the other two chemicals are administered to paralyze the lungs and stop the heart.

The companies did not disclose which of their drugs Arkansas will use during the executions.

(Reporting by Brendan O'Brien; Editing by Chizu Nomiyama)