(657e) Nucleation Behavior of Eszopiclone - Butyl Acetate Solutions from Metastable Zone Widths
- Conference: AIChE Annual Meeting
- Year: 2017
- Proceeding: 2017 Annual Meeting
- Group: Pharmaceutical Discovery, Development and Manufacturing Forum
- Time: Thursday, November 2, 2017 - 9:40am-10:05am
Experimental data on the critical supercooling âTmax, a measure of metastable zone width (MSZWs), as a function of saturated temperature T0 and cooling rate R were analyzed to describe the nucleation behavior of unseeded eszopiclone-butylacetate solutions. The NÃ½vltâs semiempirical model and Sangwalâs theory were employed, respectively. And moreover, we propose a modified model based on the Sangwalâs theory in which the nucleation parameters are not dependent on saturation temperature T0 and nucleation temperature T1 which can fit the experimental data better than Sangwalâs theory. Furthermore, the pre-exponential A and solid â liquid interfacial energy Î³ can be obtained by employing this modified model, thus, sheds light on the relationship between nucleation parameters and the cooling rate R. Meanwhile, based on the Classical Nucleation Theory, with the estimated interfacial energies from the slope in the modified model, the critical nucleus size and critical Gibbs free energy were calculated and discussed. Then based on the Sangwalâs theory, the nucleation activation barrier is found to be dependent on ln R with an exponential relationship, hence, the relationship between nucleation barrier and pre-exponential A can be constructed. At last, the effects of agitation rate and working volume on MSZWs were investigated and discussed.