What is the difference between these two sentences:
- Scientists are developing new drugs to treat arthritis
- Scientists are creating new drugs to treat arthritis
There's not much difference in this example. "Developing" new drugs puts more emphasis on the amount of work required to create the drugs—they cannot simply be created with what they already have, but need to be developed through research and testing.
Given that and the fact that most drugs do require a hefty amount of research and development, I'd typically lean toward "developing," but either is perfectly fine. A case where I'd strongly suggest "creating" is in a future where we are confident in a specific process for creating a new drug that can be quickly applied to new diseases—for instance, Moderna's COVID-19 vaccine, which was apparently created in two days. Of course, it took a long time to test, but the actual creation was straightforward, given what they'd already developed.
Creating is the act of bringing something into existence that did not exist before, while developing is the act of growing something into a more mature / advanced state.
So you would create the drug and then develop it.
Hence in terms of your sentences. When you talk about “creating” a new drug, it would imply there is no drug in currently in existence. Whilst when you talk about “developing” a drug, it would imply that there is already one, but you are improving it.
In normal conversation most people will not dwell on the subtle difference.