title: Micro-CT in drug delivery.
abstract: Micro-computed tomography (micro-CT) has not to date been fully exploited in the area of controlled drug delivery despite its capability for providing detailed, 3-D images of morphology and the opportunity this presents for exploring the relationships between delivery device formulation, structure and performance. Micro-CT was used to characterize the internal structure of polycaprolactone (PCL) matrix-type devices incorporating soluble particulates (lactose Mw 342.30, gelatin Mw 20-25kDa) as models of hydrophilic bioactives or pore-forming excipients. Micro-CT images confirmed that the lactose and gelatin particles were uniformly dispersed throughout the PCL phase and that efficient delivery of 95-100% of each species in 9days involved transport from the matrix core. Quantitative analysis of micro-CT images provided values for matrix macroporosity, which were within 15% of the theoretical value and revealed uniform porosity throughout the samples. Total release of protein occurred in 9days (PBS, 37 degrees C) from matrices containing a high protein load (44%w/w) and was independent of particle size. Measurements of equivalent pore diameter and frequency distribution identified a large population of sub-40microm pores in each material, indicative of a high density of connecting channels between particles which facilitates protein transport through the matrices.
authors.affiliation: The University of Queensland, School of Pharmacy, Brisbane, Qld, Australia.
authors.forename: Yiwei
authors.initials: Y
authors.lastname: Wang
authors.forename: David F
authors.initials: DF
authors.lastname: Wertheim
authors.forename: Allan S
authors.initials: AS
authors.lastname: Jones
authors.forename: Allan G A
authors.initials: AG
authors.lastname: Coombes
mesh_terms: D003692:Delayed-Action Preparations / Q000737:chemistry*; D004058:Diffusion; D016503:Drug Delivery Systems / Q000379:methods*; D005079:Excipients / Q000032:analysis / Q000737:chemistry; D021621:Imaging, Three-Dimensional / Q000379:methods; D004364:Pharmaceutical Preparations / Q000032:analysis / Q000737:chemistry; D011091:Polyesters / Q000737:chemistry; D016062:Porosity; D011506:Proteins / Q000032:analysis / Q000737:chemistry; D013997:Time Factors; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D003692:Delayed-Action Preparations; D005079:Excipients; D004364:Pharmaceutical Preparations; D011091:Polyesters; D011506:Proteins; C016240:polycaprolactone