Limited work has been done to date concerning polymorph quantitation using ssNMR.  Most studies require an internal standard and/or calibration curve.  Crystal Pharmatech researchers have developed an assay utilizing solid-state NMR together with a least-squares linear combination fitting procedure to detect and quantify percentages of polymorphic forms in mixtures. This assay was validated using the polymorph system of an active pharmaceutical ingredient (API).  This technology can be used in any API or formulation system and takes into account all instrument variability, however, requires pure reference samples.  Crystal Pharmatech has also developed methodology that uses a self-modeling mixture analysis program that can be applied to any process that decays exponentially (T2, T1rho, modified-T1 experiment).  Using this methodology, we can design the appropriate experiment that can elucidate the number of phases in your samples without any a-priori knowledge of the system.