Based on the above stated considera

Based on the above stated considerations, an applicant or drug substance manufacturershould investigate whether a drug substance is capable of existing in different solid stateforms. Solid state form in this context refers to amorphous and crystalline forms,hydrates, and solvates. The information can include studies of (1) the conditions that leadto the formation of one or another solid state form or (2) the conditions under which onesolid state form can be converted or equilibrated with another. Applicants do not need toinvestigate the occurrence of different forms under conditions that deviate significantlyfrom the conditions used in the manufacturing processes for the drug substance and drugproduct. However, screening a variety of solvents with different polarities and hydrogenbonding properties can be valuable for early detection of other polymorphs.At an appropriate stage of development, the potential for interconversion of solid stateforms should usually be investigated in stability studies. A summary of theseinvestigations should be included in S.3.1 of the application even if no other forms werefound. Information on differences in particle size distribution or crystal habit (shape) can also be important in some circumstances.