title: Quantifying electrostatic interactions in pharmaceutical solid systems.
abstract: Triboelectrification of pharmaceutical powders with stainless steel and polymer contact surfaces was investigated. alpha-Lactose monohydrate, from 90 to 125 up to 355-500 microm, was used to quantify electrostatic interactions with negligible powder adhesion to the contact surface. Size fractions down to 53-75 microm alone and in binary mixtures with <10 microm lactose or micronized salbutamol were used to investigate triboelectrification with powder adhered to the contact surface. Triboelectrification was performed in a cyclone charger fitted with interchangeable contact surfaces of steel and polymers, representing the surfaces of pharmaceutical processing and manufacturing equipment, packaging materials and components of dry powder inhaler devices. The results for single component powders showed charge acquisition was inversely related to particle size, where contact surface contamination was negligible. However, with particulate contamination, triboelectrification was more complex due to particle collisions with clean and contaminated contact surfaces. Analysis of adhered and non-adhered powder provided information about changes in composition of two component powders during triboelectrification. Particle size and chemical analyses showed that composition changes of mixtures may be related to powder/contact surface affinity and interparticulate forces for separation of components in a cohesive mix during triboelectrification.
authors.affiliation: Institute of Pharmacy, School of Sciences, Pasteur Building, Institute of Pharmacy, University of Sunderland, Sunderland SR23SD, UK. growley@btinternet.com
authors.forename: G
authors.initials: G
authors.lastname: Rowley
mesh_terms: D002626:Chemistry, Pharmaceutical; D020099:Coated Materials, Biocompatible; D004347:Drug Interactions; D007785:Lactose; D010316:Particle Size; D011208:Powders; D055672:Static Electricity
chemical_list: D020099:Coated Materials, Biocompatible; D011208:Powders; D007785:Lactose