Browsing Life Sciences by Author "Edwards, Anthony D."
Crystallisation of pure anhydrous polymorphs of carbamazepine by solution enhanced dispersion with supercritical fluids (SEDS¿).Edwards, Anthony D.; Shekunov, Boris Yu.; Kordikowski, Andreas; Forbes, Robert T.; York, Peter (2001)Pure anhydrous polymorphs of carbamazepine were prepared by solution-enhanced dispersion with supercritical fluids (SEDSTM). Crystallization of the polymorphs was studied. Mechanisms are proposed that consider the thermodynamics of carbamazepine, supersaturation in the SEDSTM process, and the binary phase equilibria of organic solvents and the carbon dioxide antisolvent. -Carbamazepine was crystallized at high supersaturations and low temperatures, -carbamazepine crystallized from a methanol-carbon dioxide phase split, and -carbamazepine crystallized via nucleation at high temperatures and low supersaturation.
Time-resolved x-ray scattering using synchrotron radiation applied to the study of a polymorphic transition in carbamazepine.Forbes, Robert T.; Edwards, Anthony D.; Shekunov, Boris Yu.; Grossmann, J,; York, Peter (2001)The thermodynamic status of -carbamazepine has been clarified using equilibrium solubility measurements, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), heated X-ray powder diffraction (XRPD), and temperature-controlled X-ray scattering techniques. -Carbamazepine is the least stable of the three well-characterized anhydrous polymorphs of carbamazepine at 25°C. In addition, it was confirmed that -carbamazepine undergoes an exothermic transition to -carbamazepine at 130°C. The novel technique of time-resolved simultaneous small- and wide-angle X-ray scattering has been successfully applied to monitor this transition in situ. It was concluded that -carbamazepine has a monotropic relationship with -carbamazepine.