title: Investigation of a new mathematical model for compression of pharmaceutical powders.
abstract: A new compaction equation, the log-exp model: V=V(l)-w log(P)+V(e) exp(P/P(m)) is presented. The model presumes that two compaction processes: a logarithmic and an exponential decline may be active simultaneously. Using non-linear regression techniques the model gives an excellent fit to a number of model substances with wide differences in compaction behaviour. Compared to the Kawakita equation the model covers a broader range of the compaction profile. The new model and the Cooper and Eaton equation fit the data on the same level, but the parameters derived from the log-exp model seems to have more discriminative power between substances and have a close relation to the apparent plastic or brittle densification mechanism. The log-exp model has potential as a tool in estimation of the strength of agglomerated materials. A proposal for a set-up to an iterative non-linear regression calculation in a spreadsheet program is attached.
authors.affiliation: The Royal Danish School of Pharmacy, Department of Pharmaceutics, Universitetsparken 2, DK-2100 Copenhagen, Denmark. jms@dfh.dk
authors.forename: J M
authors.initials: JM
authors.lastname: Sonnergaard
mesh_terms: D019245:Compressive Strength; D008956:Models, Chemical; D008962:Models, Theoretical; D017711:Nonlinear Dynamics; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011208:Powders / Q000737:chemistry*
chemical_list: D004364:Pharmaceutical Preparations; D011208:Powders