Noninvasive in vitro and in vivo Monitoring of Drug Delivery Processes by Electron Spin Resonance, Benchtop-NMR and Multispectral Optical Imaging

The performance of a drug delivery system in vitro and in vivo is a result of complex interactions between the drug, the carrier and the release environment. The rationale design and improvement requires appropriate analytical methods. It will be illustrated how electron spin resonance (ESR, EPR), benchtop-NMR and multipspectral optical Imaging can be used to monitor drug delivery processes noninvasively in vitro and in vivo. Examples range from in situ implants to stimulus responsive drug release from polymer conjugates. Unique information on the microclimate (viscosity, pH, polarity) can be obtained.