Derivatization Strategies for the Detection of Triamcinolone Acetonide in Cartilage by Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging

Abstract

Osteoarthritis (OA), characterized by degeneration of the cartilaginous tissue in articular joints, severely impairs mobility in many people worldwide. The degeneration is thought to be mediated by inflammatory processes occurring in the tissue of the joint, including the cartilage. Intra-articular administered triamcinolone acetonide (TAA) is one of the drug treatments employed to ameliorate the inflammation and pain that characterizes OA. However, the penetration and distribution of TAA into the avascular cartilage is not well understood. We employed matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), which has been previously used to directly monitor the distribution of drugs in biological tissues, to evaluate the distribution of TAA in human cartilage after in vitro incubation. Unfortunately, TAA is not easily ionized by regular electrospray ionization (ESI) or MALDI. To overcome this problem, we developed an on-tissue derivatization method with Girard's reagent T (GirT) in human incubated cartilage being able to study its distribution and quantify the drug abundance (up to 3.3 ng/μL). Our results demonstrate the depth of penetration of a corticosteroid drug in human OA cartilage using MALDI-MSI.

Mass Spectrometry Imaging: A Review of Emerging Advancements and Future Insights

“…For example, the Girard T (GirT) reagent has been applied successfully to several steroids, including testosterone and triamcinolone acetonide. 31,53 Other steroids (e.g., tetrahydrocannabinal) have also been targeted using 2-fluoro-1-methylpyridinium p -tolunesolfonate as a derivatization agent. 29 N-glycans (Figure 2), fatty acids, and neurotransmitters have all been targets through other, unique on-tissue assays.…”

“…36 Because of their structure, metabolites can have poor ionization efficiency, which has prompted the development of many derivatization schemes to increase access to metabolites in samples. 28,31,53 Just like lipids, a wide variety of ionization techniques lends well to metabolites, including MALDI, 12,14,20,28,29,31,36,137,233–236 DESI, 2,218,237 and LAESI, 69 although, based upon citations alone, MALDI is by far the most popular. This is actually surprising, as most matrixes used for MALDI analysis are small organic compounds, meaning they can have their own interfering ions in the metabolite mass range at high concentrations, masking some possible signals of interest.…”

“…Biological samples (e.g., tissue) will likely continue to be utilized for method development and proof-of-principle experiments due to their natural sample complexity and variety. 31,33,222,229,239 This trend is especially true for clinically inventoried samples, since strategies for analyzing FFPE tissue samples are in high demand. 49,51,100,213 For example, tissue microarrays, which are usually FFPE samples, provide unique opportunities for researchers to perform high-throughput screening of different diseases with little variation in preparation.…”

Derivatization for detection of abscisic acid and 12‐oxo‐phytodienoic acid using matrix‐assisted laser desorption/ionization imaging mass spectrometry

“…Recently, on‐tissue chemical derivatization (OTCD) methods have been developed for MALDI‐IMS to increase the detection sensitivities for specific molecules . Girard's T (GirT) is one of the OTCD reagents used in MALDI‐IMS.…”

“…It reacts with ketones and forms the positively charged hydrazone derivatives, resulting in selective improvement of target ionization efficiency and ion suppression. In addition, the increased m/z value helps to avoid interference from the matrix background in the lower mass range . However, optimization of the OTDC conditions for ABA and OPDA is necessary, because OTCD of ABA and OPDA for MALDI‐IMS has not been previously reported.…”