Retrospective Drug Testing: Can the Skin Provide a Record of Drug Taking History?

  • Jennifer Jones

Student thesis: Doctoral ThesisPhD


It has been shown that prolonged systemic presence of a drug can cause a buildup of that drug in the skin. This drug ‘reservoir’, if properly understood, couldprovide useful and important information about the recent drug-taking history ofa patient. In this thesis we create three mathematical models which combine toexplore the potential for a drug reservoir to form in the skin and be collected asa method of monitoring compliance. The first model is used to characterise timedependent drug concentrations in plasma and tissue following a customisable drugregimen. Outputs from this model provide boundary conditions for the second,spatio-temporal model of drug build-up and concentration profile in the skin. Thisthen provides initial conditions for the final model which predicts the extraction.These models are then used to identify the scenarios which have the greatestpotential for successfully monitoring patient compliance via the skin.We focus in particular on drugs that are highly bound as this will restricttheir potential to move freely into the skin but which are lipophilic so that, in theunbound form, they would demonstrate an affinity to the outer layers of the skin(which are built around a lipid matrix). We highlight how this study might beused to inform future experimental design and data collection in order to providerelevant parameter estimates for reservoir formation and its potential to contributeto enhanced drug monitoring techniques.
Date of Award21 Nov 2017
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorJane White (Supervisor), Begona Delgado-Charro (Supervisor) & Richard Guy (Supervisor)


  • Mathematical modelling
  • Skin
  • Reverse iontophoresis
  • tape stripping
  • Drug Monitoring
  • Iontophoresis

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