It is well documented that polymorphism can have a profound effect on the bioavailability of your bulk active, and indeed screening is a requirement by the regulatory bodies (see diagram of screening process from ICH Q6A).
It pays to start thinking about the solid form sooner rather than later, as most molecules exhibit polymorphism, asking some simple questions:
- Do you Know the physical and chemical stability in the formulation?
- Crystalline vs. anorphous drug substance and the acceptable final form for your prodcuct
- Previous experiance with stablizing agents (if amorphous dispersions)
- Dosage form to be developed and teh actice loading you need of the active