Methods of studying aging and stabilization of spray-congealed solid dispersions with carnauba wax. 1. Microcalorimetric investigation.
Rapidly cooled materials are often unstable as a result of changes in their physical properties due to imperfect crystallization. In the process of spray-congealing, melted material is atomized into droplets which very quickly solidify. This increases the possibility of the material crystallizing in different metastable forms. In this study it is shown that isothermal microcalorimetry can be used to observe the change in the thermodynamic state of spray-congealed carnauba wax during storage. In order to accelerate the thermodynamic change in the spray-congealed wax, three annealing procedures have been developed and compared using isothermal microcalorimetry. By means of annealing, a spray-congealed product closer to a thermodynamically stable state has been achieved.
Emås
M
M
AstraZeneca, Pharmaceutical & Analytical R&D, S-151 85, Södertälje, Sweden. margareta.emas@astrazeneca.com
Nyqvist
H
H
D002151:Calorimetry; D003460:Crystallization; D004339:Drug Compounding; D004355:Drug Stability; D011208:Powders / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D013997:Time Factors; D014885:Waxes / Q000737:chemistry*
D011208:Powders; D014885:Waxes