A biphasic diffusion model of drug release from medical implant coatings

  • Keelin Elizabeth Quirk

Student thesis: Master's Thesis


Vascular diseases remain one of the leading causes of death worldwide. Two common treatments for such diseases, grafts and stents, have improved considerably over time with the advent of local drug release technology. However, these treatments have limitations, namely blood clots for drug-eluting stents and infection for grafts. While the use of in vitro and in vivo models of drug release from these devices has not yet led to optimised designs to limit such effects, in this context modelling drug release apeears to be a useful research tool for improving these devices. The biphasic diffusion model of drug release presented in this study used a Crank-Nicolson scheme implemented in Matlab to numerically solve a one-dimensional biphasic diffusion equation and quantify in vitro release data. The coefficients which best fit in vitro release data for five drug coating layers were determined for the original time-dependent biphasic model. Release from a novel electrospray-coated sirolimus-eluting stent and a rifampicin-eluting PLGA graft coating was modelled to explore the utility of the model on coatings designed for both stents and grafts. The biphasic diffusion model was superior to a single-phase diffusion model and equally accurate when compared with a time-dependent biphasic model which mechanistically described polymer degradation from the graft coating While further research into the mechanisms which impact release rate among different coating layers is needed, the model showed promise as a predictive tool of in vitro release from new coatings as well.
Date of Award25 Oct 2021
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsUniversity of Strathclyde
SupervisorChristopher McCormick (Supervisor) & Asimina Kazakidi (Supervisor)

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