Andrea Bertarello,¹ Pierrick Berruyer,¹ Urban Skantze,² Sepideh Hagvall,³ Samiksha Sardana,⁴ Malvika Sardana,⁴ Charles S. Elmore,⁴ Rodrigo J. Carbajo,^5,* Elisabetta Chiarparin,⁵ Staffan Schantz,⁶ Lyndon Emsley¹

¹ Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, ² Advanced Drug delivery, Pharmaceutical Science, AstraZeneca, Gothenburg, Sweden, ³ Early CVRM, Biopharmaceutical R&D, AstraZeneca, Gothenburg, Sweden, ⁴ Pharmaceutical Science, R&D, AstraZeneca, Gothenburg, Sweden, ⁵ Chemistry, Oncology R&D, AstraZeneca, Cambridge, United Kingdom, ⁶ Oral Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Gothenburg, Sweden
^* Now left AstraZeneca

Knowledge of intracellular drug concentration gives information on uptake, trafficking and target engagement, providing a better understanding of function and efficacy. Detection should ideally be performed non-destructively, and without modification of either the drug or the target. It requires the capability to detect low amounts of the molecule of interest, often in the µM – nM range. However, there is currently no experimental technique that can provide direct intracellular drug concentrations satisfying simultaneously all these requirements.

Solution NMR is a well-established technique for the non-destructive, tag free-quantification of analytes, and over the last decade or so has been extensively used for the characterization of molecules (e.g. proteins), in their native cellular environments. However, NMR is hindered by low sensitivity, and biased to the study of molecules in fast motional regime, which is not always the case inside the cell. Magic-angle spinning dynamic nuclear polarization (MAS DNP) can be used to overcome these two drawbacks, providing higher sensitivity and allowing the detection of immobilized species.[1]

Here we present preliminary results demonstrating how MAS DNP can be successfully used for the detection and the quantification of molecules in sub-µM concentration, compatible with intracellular conditions. Our results are a first step towards the use of MAS DNP for the study of intracellular drug trafficking.

[1] J.Schlagnitweit, S. Friebe Sandoz, A. Jaworski, I. Guzzetti, F. Aussenac, R. J. Carbajo, E. Chiarparin, A. J. Pell, K. Petzold, ChemBioChem, 2019, 20, 2474 – 2478