Micro-CT imaging technique to characterize diffusion of small-molecules

Tina Khazaee; Chris J. D. Norley; Hristo N. Nikolov; Steven I. Pollmann; David W. Holdsworth

doi:10.1117/12.2548624

28 February 2020 Micro-CT imaging technique to characterize diffusion of small-molecules

Tina Khazaee, Chris J. D. Norley, Hristo N. Nikolov, Steven I. Pollmann, David W. Holdsworth

Proceedings Volume 11317, Medical Imaging 2020: Biomedical Applications in Molecular, Structural, and Functional Imaging; 1131715 (2020) https://doi.org/10.1117/12.2548624
Event: SPIE Medical Imaging, 2020, Houston, Texas, United States

Abstract

Optimization and characterization of small-molecule diffusion are important in the development of drug-delivery systems. For example, the delivery of local antibiotics is an important component of therapy for orthopedic devicerelated infections (ODRI). However, despite its wide use, the exact elution mechanism is not yet fully understood. In this study, we developed a quantitative, non-destructive, micro-CT technique to characterize 2D diffusion of small-molecules in a tissue-equivalent phantom. Our objective is to use a radio-opaque molecule (Iohexol; molecular weight (MW) 821 Da) as a surrogate for small-molecule antibiotics (e.g., Vancomycin; MW 1449 Da) to characterize diffusion from a finite, cylindrical-core carrier into an agar, tissue-equivalent, sink. A single-phase diffusion experiment was performed to validate our micro-CT imaging method. A two-part phantom consisted of an inner, cylindrical, agar core loaded with Iohexol as a drug-surrogate, directly communicating with an outer annulus of pure agar. The estimate of a single-phase diffusion coefficient for agar was derived from the analysis of 2D radial diffusion distance. We then applied the validated method to evaluate diffusion in two-phases, using calcium-sulphate matrices loaded with Iohexol eluting into an agar tissue-equivalent sink. Image acquisition was performed at regular intervals up to 25 days. Cumulative release amount was used to calculate diffusion coefficients in two-phase phantoms. Iohexol diffusion coefficient was 2.6 ×10^-10 m2 s^-1, 0.46 ×10^-10 m² s^-1, 0.85 ×10^-10 m² s^-1 through agar, Stimulan, and Plaster of Paris, respectively. This approach could be used to validate drug delivery in the development of new carrier structures and materials.

Conference Presentation

Citation Download Citation

Tina Khazaee, Chris J. D. Norley, Hristo N. Nikolov, Steven I. Pollmann, and David W. Holdsworth "Micro-CT imaging technique to characterize diffusion of small-molecules", Proc. SPIE 11317, Medical Imaging 2020: Biomedical Applications in Molecular, Structural, and Functional Imaging, 1131715 (28 February 2020); https://doi.org/10.1117/12.2548624

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available