How to quantify dissociated amount of solvent/hydrate in solid oral dosage form ?

For "X" drug, I prepared solvate "Xz." Using "Xz" I prepared Granules Dosage Form. Over the period of stability I found that solvate "z" is dissociated from Granules Formulation. Now in my Granules there is separate drug "X" and solvate"z". I analyzed changes by Head Space Gas Chromatography but it gives me total amount of Solvate. From the GC result it is not clear that quantified amount is correlated to total amount of solvate or dissociated amount. My requirement is to know exact dissociated amount of solvate from "drug-solvate." Please suggest me most suitable and sophisticated method to determine only dissociated quantity of solvate from "drug-solvate"

Is there any case where Innovator/Generic provided such type of analysis for thier stand in court ? 

Please provide answer either as comment or in my mail box. My Mail Id is dabhi.jayendra@gmail.com