Officials have continued administering a new experimental drug to patients suffering from Ebola this week, despite an ongoing U.N. debate on its safety between medical ethicists.

On Monday, Spain imported the controversial Zmapp drug, made by Mapp Biochemical Inc. in San Diego, for use on a Spanish missionary priest who was evacuated from Liberia last week after testing positive for Ebola.

Spanish officials asked for permission to use the drug under legislation stating that it is legal to use an unauthorized medication on patients with a life-threatening illness, according to reports from The Associated Press.

The ethics of using the drug have been debated this week because Zmapp has never been tested on humans.

Zmapp is a mixture of three antibodies engineered to recognize Ebola and bind to infected cells so the immune system can kill them, according to The Hindu.

Currently, there are very few doses of Zmapp available in the world, but Mapp Biochemical Inc. says that it is working with government agencies to make the drug more readily available, reports The Vancouver Sun. 

This drug was first used on the two Americans diagnosed with Ebola in Liberia that were treated in Atlanta and are still being held in isolation. One of the patients was reported to be improving last week. Because the drug was never tested on humans before, scientists cannot say for sure whether the drug is playing a part in the patient's improvement, according to AP.

Since the experimental drug was released, at least one country in West Africa has been inquiring about having access to the drug. Over 1,000 people have been killed so far in the West Africa outbreak, which has been deemed an international health emergency by The World Health Organization.