MD Simulation for Unknown Drugs Molecules

GROMACS version:
GROMACS modification: Yes/No
Here post your question ’
I have 10 drug molecules from FDA (not in any databases) for which I want to perform MD Simulations. Somehow not able to generate the topology file for the drugs (ligands) due to their unsatisfied valances.

Can you suggest or guide me to generate a simulation without an STR file for these unknown molecules?

There are several online and offline tools to generate topology for ligands. You can try with the following servers
CHARMM- GUI
ATB server
You also can refer Gromacs tutorial for protein-ligand complex for further understanding

You can’t generate a topology without having a complete structure, including all H atoms present. If you have unsatisfied valences, you need to complete the molecule. No server or program will work with chemically incomplete species.