An in-depth knowledge of the API molecular and crystal structure is of great importance in order to understand crystal properties e.g. density, molecular packing, surface, etc.
Our crystallographic know-how allows us to determine API structure from single crystal analysis using X-ray single crystal diffractometry to compute "error free" powder diffraction patterns for comparison with those measured on bulk materials thus assessing amorphous content.
A crystal structure can be determined from a powder diffraction pattern using the Rietveld method, but in most cases identifying the lattice type and dimensions of the unit cell is sufficient. Once all the peaks in the diffraction pattern generated by a pure active ingredient have been indexed, a drug can be uniquely fingerprinted.
The characteristics of the unit cell, together with its chemical composition, can also be used to predict the morphology and physical properties of a drug.
Structural analysis using XRPD is particularly valuable for characterizing alternative forms of registered drugs when patents are about to expire.