Direct Analysis of Pharmaceutical Drugs Using Nano-DESI MS

Abstract

Counterfeit pharmaceutical drugs imply an increasing threat to the global public health. It is necessary to have systems to control the products that reach the market and to detect falsified medicines. In this work, molecules in several pharmaceutical tablets were directly analyzed using nanospray desorption electrospray ionization mass spectrometry (nano-DESI MS). Nano-DESI is an ambient surface sampling technique which enables sampling of molecules directly from the surface of the tablets without any sample pretreatment. Both the active pharmaceutical ingredients (APIs) and some excipients were detected in all analyzed tablets. Principal component analysis was used to analyze mass spectral features from different tablets showing strong clustering between tablets with different APIs. The obtained results suggest nano-DESI MS as future tool for forensic analysis to discern APIs present in unknown tablet samples.

Figure 1

Photograph of the nano-DESI MS setup for online sampling and analysis from the surface of a fractured tablet.

Figure 2

Mass spectra from direct tablet analysis using nano-DESI MS; (a) ibuprofen containing tablet, showing ibuprofen specific fragment ions at m/z 119 and 161, (b) paracetamol containing tablet, showing paracetamol specific fragment ions at m/z 110 and 152, (c) sildenafil containing tablet, showing specific sildenafil m/z 475 ion and m/z 513 ion, and (d) tadalafil containing tablet, showing specific tadalafil m/z 412 ion and lactose m/z 365 ion.

Figure 3

PCA scores of all samples. Matrix consisted of 63 samples and 112 ions. Important ions contributing to the new PCs according to the X-loadings are m/z 110, 152, 365, 366, 475, and 476. The red circle shows ibuprofen containing medicines, the yellow circle shows tadalafil containing samples, and the green circle shows Viagra-type tablets.