Monitoring dexamethasone skin biodistribution with ex vivo MALDI-TOF mass spectrometry imaging and confocal Raman microscopy

• Published in: International journal of pharmaceutics Vol. 636; p. 122808
• Main Authors: Pena-Rodríguez, Eloy, García-Berrocoso, Teresa, Vázquez Fernández, Ezequiel, Otero-Espinar, Francisco J., Abian, Joaquin, Fernández-Campos, Francisco
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05.04.2023
• Subjects: Biodistribution; Confocal Raman; Dexamethasone; MALDI-MSI; Microscopy; Nanoparticle; Semiquantitative; Skin; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Tissue Distribution; Confocal Raman; Skin; MALDI-MSI; Semiquantitative; Nanoparticle; Biodistribution
• ISSN: 0378-5173; 1873-3476
• DOI: 10.1016/j.ijpharm.2023.122808

[Display omitted] Two of the most promising techniques in terms of ex vivo skin imaging and quantifying are confocal Raman microscopy and MALDI-TOF mass spectrometry imaging (MALDI-TOF MSI). Both techniques were set up, and the semiquantitative skin biodistribution of previously developed dexamethasone (DEX) loaded lipomers was compared using Benzalkonium chloride (BAK) as a tracer of the nanoparticles. In MALDI-TOF MSI, DEX was derivatised with GirT (DEX-GirT) and the semiquantitative biodistribution of both DEX-GirT and BAK was successfully obtained. The amount of DEX measured by confocal Raman microscopy was higher than that measured by MALDI-TOF MSI, but MALDI-TOF MSI proved to be a more suitable technique for tracing BAK. An absorption-promoting tendency of DEX loaded in lipomers versus a free-DEX solution was observed in confocal Raman microscopy. The higher spatial resolution of confocal Raman microscopy (350 nm) with respect to MALDI-TOF MSI (50 μm) allowed to observe specific skin structures like hair follicles. Nevertheless, the faster sampling rate of MALDI-TOF-MSI, permitted the analysis of larger tissue regions. In conclusion, both techniques allowed to simultaneously analyze semiquantitative data together with qualitative images of biodistribution, which is a very helpful tool when designing nanoparticles that accumulate in specific anatomical regions.