Most pharmacies do not seem to want to be associated with the substances required to perform lethal injections. It’s considered to be a non-medical use. The Hippocratic oath specifically prohibits the administration of lethal substances. Many pharmacies adhere to this standard.
The State of Ohio is turning to compounding pharmacies which formulate medications in small batches. Small batch formulation does not necessarily mean that compounding pharmacies are less safe than the big boys. Despite the outbreak of fungal meningitis in 2012 which originated at a compounding pharmacy in New England, compounding pharmacies have provided much needed medications for many years.
However, the regulations for compounding pharmacies are different from those that are used in larger scale manufacturing facilities. In a large manufacturing plant there is a long and very complicated process for compliance and validation for each formulation. Because compounding pharmacies are formulated in small batches, the process for each formulation cannot be validated individually. However, the lab technicians at compounding pharmacies are highly trained and should be able to detect faults in the compounding process. State legislatures currently regulate compounding pharmacies so there is no national standard.
All of this begs the question: will the move to compounding pharmacies result in a higher risk for pain or complications during the administration of lethal injections? That question has not been subject to rigorous scientific study, so it remains open. However, the fact that the state of Ohio no longer has the option to procure medications through mainstream distribution channels means that there is no choice. Even if lethal injection drugs from compounding pharmacies are more prone to produce complications then the state will have no alternative but to procure the drugs from them.