Automated and enhanced extraction of a small molecule-drug conjugate using an enzyme-inhibitor interaction based SPME tool followed by direct analysis by ESI-MS
We report a novel, fast, and automatic SPME-based method capable of extracting a small molecule-drug conjugate (SMDC) from biological matrices. Our method relies on the extraction of the drug conjugate followed by direct elution into an electrospray mass spectrometer (ESI-MS) source for qualitative and quantitative analysis. We designed a tool for extracting the targeting head of a recently synthesized SMDC, which includes acetazolamide (AAZ) as high-affinity ligand specific to carbonic anhydrase IX. Specificity of the extraction was achieved through systematic optimization. The design of the extraction tool is based on noncovalent and reversible interaction between AAZ and CAII that is immobilized on the SPME extraction phase. Using this approach, we showed a 330% rise in extracted AAZ signal intensity compared to a control, which was performed in the absence of CAII. A linear dynamic range from 1.2 to 25 μg/ml was found. The limits of detection (LOD) of extracted AAZ from phosphate-buffered saline (PBS) and human plasma were 0.4 and 1.2 μg/ml, respectively. This with a relative standard deviation of less than 14% (n = 40) covers the therapeutic range.
KeywordsCapillary gap sampler Solid-phase microextraction Targeted drug delivery Small molecule-drug conjugates Carbonic anhydrase Acetazolamide
We gratefully thank Dr. Christof Fattinger (Roche) for his support in sampler development. Moreover, we thank the Scientific Center for Optical and Electron Microscopy (ScopeM), a central technology platform of ETH Zurich, for providing us with resources and services in electron microscopy. Finally, we thank the Swiss National Science Foundation (SNSF) for funding this project (Grant numbers 200020-159929 & 200020-178765).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest
- 3.van der Veldt AAM, Hendrikse NH, Smit EF, Mooijer MPJ, Rijnders AY, Gerritsen WR, et al. Biodistribution and radiation dosimetry of 11C-labelled docetaxel in cancer patients. Eur J Nucl Med Mol Imaging. 2010;37:1950–8. https://doi.org/10.1007/s00259-010-1489-y.CrossRefPubMedPubMedCentralGoogle Scholar
- 4.van der Veldt AA, Lubberink M, Mathijssen RH, Loos W, Herder GJ, Greuter HN, Comans EF, Rutten H, Eriksson J, Windhorst AD, Hendrikse H, Postmus PE, Smit EF, Lammertsma AA. Towards prediction of efficacy of chemotherapy: a proof of concept study in lung cancer patients using [11C] docetaxel and positron emission tomography. Clin Cancer Res clincanres.3779.2012. 2013 https://doi.org/10.1158/1078-0432.CCR-12-3779.CrossRefGoogle Scholar
- 5.van der Meel R, Vehmeijer LJC, Kok RJ, Storm G, van Gaal EVB. Ligand-targeted particulate nanomedicines undergoing clinical evaluation: current status. In: Prokop A, Weissig V, editors. Intracellular delivery III: market entry barriers of Nanomedicines. Cham: Springer International Publishing; 2016. p. 163–200.CrossRefGoogle Scholar
- 10.Kurzrock R, Gabrail N, Chandhasin C, Moulder S, Smith C, Brenner A, et al. Safety, pharmacokinetics, and activity of GRN1005, a novel conjugate of angiopep-2, a peptide facilitating brain penetration, and paclitaxel, in patients with advanced solid tumors. Mol Cancer Ther. 2012;11:308–16. https://doi.org/10.1158/1535-7163.MCT-11-0566.CrossRefPubMedGoogle Scholar
- 25.Ginj M, Zhang H, Waser B, Cescato R, Wild D, Wang X, et al. Radiolabeled somatostatin receptor antagonists are preferable to agonists for in vivo peptide receptor targeting of tumors. Proc Natl Acad Sci U S A. 2006;103:16436–41. https://doi.org/10.1073/pnas.0607761103.CrossRefPubMedPubMedCentralGoogle Scholar
- 35.Almstedt K, Lundqvist M, Carlsson J, Karlsson M, Persson B, Jonsson B-H, et al. Unfolding a folding disease: folding, misfolding and aggregation of the marble brain syndrome-associated mutant H107Y of human carbonic anhydrase II. J Mol Biol. 2004;342:619–33. https://doi.org/10.1016/j.jmb.2004.07.024.CrossRefPubMedGoogle Scholar
- 39.Chapron DJ, Gomolin IH, Sweeney KR. Acetazolamide blood concentrations are excessive in the elderly: propensity for acidosis and relationship to renal function. J Clin Pharmacol. 1989;29:348–53. https://doi.org/10.1002/j.1552-4604.1989.tb03340.x.CrossRefPubMedGoogle Scholar