Eleonora Paladino oral presentation (OA3-Tue3-3-5)
3D imaging of controlled-release electrospun materials
1 CMAC - University of Strathclyde, 99 George Street, G1 1RD Glasgow, United Kingdom
2 National Physical Laboratory, Hampton Road, TW11 0LW Teddington, United Kingdom
3 Strathclyde Institute of Pharmacy and Biomedical Sciences - University of Strathclyde, , Glasgow, United Kingdom
4 Medway School of Pharmacy, University of Kent, Central Avenue, Chatham Maritime, ME4 4TB Chatham, United Kingdom
5 Cancer Research UK Formulation Unit - University of Strathclyde, , Glasgow, United Kingdom
ToF-SIMS is a new and valuable tool in drug formulation and advanced pharmaceutical manufacturing. 3D chemical imaging allows us to localize the distribution of active ingredients (API) in complex excipient matrices. In order to advance pharmaceutical manufacturing and formulation, new materials and methods to prepare tablets and tissue engineering devices are being explored.
We have successfully demonstrated the use of 2D ToF-SIMS imaging in the characterization of electrospun fibres for hernia repair  and blended fibres (synthetic and natural) for improved biocompatibility (submitted manuscript, 2017). In this report, we optimize dual beam 3D imaging methodology for the analysis of drug doped polymeric fibres systems.
Electrospinning produces small diameter fibres ranging from hundreds of nanometers to a few micrometers, the perfect size range of ToF-SIMS analysis. The selection of the API, polymer and solvent used in the electrospinning process influence the size and architecture (i.e. cavity size) of the fibres, as well as, the location and concentration of the API. These physical features influence the dissolution rate of the material and ultimately change the dosage and exposure time. The formulation parameters, not only influence drug dissolution rates, but also affects the sputter rate of the material. Therefore, fundamental studies were conducted to measure the sputter rate for various formulations and optimize 3D imaging parameters for each system. In particular, two biodegradable and biocompatible polymers (PCL and PLA) were chosen for this study. The robustness of the method and the inter-day and inter-sample repeatability of sputtering yields and depth resolutions was also investigated. Overall ToF-SIMS analyses were crucial in gaining a better understanding of the API’s disposition in various formulations and optimizing the final performance of the device.
 I.J. Hall Barrientos, E. Paladino et al., Int. J. Pharm. (517), 2017, 329–337