title: Dissolution modeling: factors affecting the dissolution rates of polydisperse powders.
abstract: The dissolution rates of two lots of hydrocortisone (fine and coarse) were simulated using a computer program based on a Noyes-Whitney-type equation. Derivations of the equation were made to compare the accuracy of simulations using spherical and cylindrical particle geometry, with and without a time-dependent diffusion layer thickness. To approximate better the shape of the hydrocortisone particles, a shape factor was used to relate cylindrical length to radius. The most accurate simulations were obtained by assuming cylindrical geometry with and without a time-dependent diffusion layer thickness for the fine and coarse hydrocortisone, respectively. The program was also modified to simulate initial particle size distributions based on the log normal probability density function.
authors.affiliation: Central Research Division, Pfizer Inc., Groton, Connecticut 06340.
authors.forename: A T
authors.initials: AT
authors.lastname: Lu
authors.forename: M E
authors.initials: ME
authors.lastname: Frisella
authors.forename: K C
authors.initials: KC
authors.lastname: Johnson
mesh_terms: D004058:Diffusion; D006854:Hydrocortisone / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D010316:Particle Size; D011208:Powders; D012984:Software; D012995:Solubility
chemical_list: D011208:Powders; D006854:Hydrocortisone