Arkansas Governor Asa Hutchinson is defending his decision to put to death seven prisoners over an 11-day period starting on Monday.
The executions have drawn international attention and have been condemned by rights groups as an "assembly line" and a violation of the US legal process.
On Thursday, two pharmaceutical manufacturers asked a federal judge to bar the state from using their drugs.
The unprecedented pace is due to one of the drugs expiring later this month.
Midazolam - one part of the three-drug lethal injection "cocktail" - is set to expire at the end of April, and has been criticised as contributing to several botched executions in other states.
Drug companies Fresenius Kabi USA and West-Ward Pharmaceuticals filed a motion as part of the federal lawsuit by the condemned inmates on Thursday, claiming that the drugs were secured in an improper manner, and could affect their ability to sell in Europe.
The companies said that it appears the drugs were procured through a third party, since the companies say they only sell to medical providers.
They also argue that the executions could limit their ability to trade in the European Union, which has prohibited the buying or selling of products used for capital punishment.
Governor Hutchinson says he is confident that the drugs will work as expected, and that he is satisfied the prison staff can handle the executions, six of which are happening over only three days.
A group of former prison officials had written to the governor in late March to say that the quick pace would place undue physical and emotional burden on prison staff.
But he dismissed that, saying that he had met them and "they don't take it lightly".
He also brushed aside the objections from religious groups, who have pointed out how the executions are set to begin just after the Easter holiday.
"I have a responsibility to the voters, I have a responsibility to my oath of office, but I also have responsibility to a higher power, God and eternity, and I understand that," he said.
"I feel comfortable in my understanding of my responsibilities both in terms of faith and scripture and in terms of as governor."
Opponents will be rallying later on Friday outside the Arkansas statehouse in Little Rock.
They are expected to be joined by former-death row inmate Damien Echols, who was freed in 2011 under a plea deal.