Is it possible to make a comparison between groups of drugs in a research without using a control group.. Is it permissible to create a research in this way?
If you have a common drug e.g Paracetamol for headache, at this case if you have developed three drugs for same purpose, you should include Paracetamol. But, in case you have developed five drugs for a specific case,such as corona, you could compare all of your drugs without a control!!. Regards.
Following up on what Medhat Elsahookie said, I think it depends on the state of knowledge in your field. In particular, if you have current "gold standard" for other treatment that is known to be effective, then a comparison to that would be preferable to a "no treatment" control group.