What do you mean? Drugs as they have been found to bind to proteins? In this case, the SuperLigand database might help you (e.g. ibuprofen). There's also the subscription-based Cambridge Structural Database. Lastly, a Google search finds DrugPort (e.g. ibuprofen).
If I understand correctly, surendra, you managed to convert to PDB but failed to view it in Discovery Studio? Perhaps try to convert it to a mol2 file (if it's not already the native format) and that would go through better.
thanks Egon W and M Kuhn for giving answer,, @ Egon as you told me download 3d model and then convert into pdb files,,,it does work,,i got coordinates of my drug in openbabel software ,,, but i got stuck when these pdb files converting into pdb viewer.my question is how do we convert these pdb files coordinates into pdb viewer? i have discovery studio software for viewing pdb files.i am not able to convert these file coordinates into pdb form for further use.