2.3. Batch crystallization experiments
These were carried out in situ with a Coulter Counter Multisizer. A contoured bottom flask
was used as the crystallization vessel. It was filled with a known amount of solvent and the agitation
rate of the impeller was set at 400 rpm. Nucleation of seed crystals and creation of supersaturation
of seed crystals and creation of supersatura tion were initiated by adding a small amount of DPH/NaOH solution to the vessel. The crystal size distribution (CSD) in the vessel was then measured throughout the experiment using a 140 orifice. The phenytoin concentration profile was also monitored by measuring the UV absorbance of a filtered, diluted aliquot of the crystallizer slurry.