It should be stressed that 91/414 does NOT deal with parallel import as such, but allows for its implementation and stresses the goal of free movement of goods :
Directive 91/414/CEE
The directive states the removal of barriers to trade as one of its main objectives right from the start. The preambles include:
The directive deals with active substances although Monographs include studies on the active as well as on a formulation.
However, it would not make sense to leave it to Member State to register different formulations that could lead to partitioning the single market hence defeating the purpose of the directive as stated in its preambles.