title: Triboelectrification of spray-dried lactose prepared from different feedstock concentrations.
abstract: Powder systems may acquire electrostatic charge during various pharmaceutical processing operations and may give rise to difficulties in handling and powder flow, mainly due to adhesion/cohesion effects. We have investigated the electrostatic charging of spray-dried lactose prepared from different feedstock concentrations using a laboratory spray-dryer. Triboelectrification of the spray-dried lactose samples was effected through contact with the stainless steel surface of either a mixing vessel or a cyclone separator. Results from both techniques showed differences in charge accumulation and particle-steel adhesion between the spray-dried lactose samples. As the feedstock concentration used to produce the spray-dried lactose was increased in the range 10-50% w/v, the mean charge on the lactose decreased from -20.8 to -1.3 nC g(-1) and -54.9 to -4.1 nC g(-1) for the mixing vessel and cyclone separator, respectively, with a corresponding decrease in adhesion. In addition, as the feedstock concentration was increased from 10 to 50% w/v, decreases were obtained in surface area values (1.06 to 0.56 m2 g(-1)), pore diameter (198.7 to 83.5 microm) and pore volume (1.09 to 0.75 cm3 g(-1)), and together with differences in crystal form correlated with the charge and adhesion results. The results suggested that the feedstock concentration could have a considerable influence on the charging and adhesional properties of spray-dried lactose. This may have relevance during pharmaceutical processing and manufacturing operations.
authors.affiliation: Institute of Pharmacy and Chemistry, University of Sunderland, UK.
authors.forename: O E
authors.initials: OE
authors.lastname: Cassidy
authors.forename: P A
authors.initials: PA
authors.lastname: Carter
authors.forename: G
authors.initials: G
authors.lastname: Rowley
authors.forename: D R
authors.initials: DR
authors.lastname: Merrifield
mesh_terms: D000821:Animal Feed; D005079:Excipients; D005524:Food Technology / Q000379:methods*; D007785:Lactose; D011208:Powders; D055672:Static Electricity
chemical_list: D005079:Excipients; D011208:Powders; D007785:Lactose