Page 10 - Shimadzu Journal vol.2 Issue2

New Technology 69

can minimise this drug toxicity. Our data clearly demonstrate that the
surrounding tissues was quite low compared with PTX alone. These
observations support the low incidence of peripheral neuropathy
distribution of rPTX from NK105 in the peripheral nerve and

when PTX is administered as NK105. This is the first report describing the precise distribution of a DDS drug by MSI, a new technique developed by our lab and others. Notably, we successfully visualise and quantified the distribution of a non-radiolabeled and non-chemically modified drug in various frozen tissue slices microscopically. In addition to PTX, we have successfully visualised other anticancer agents, including SN-38, epirubicin, and monomethyl auristatin E (MMAE) (data not shown). This success indicates that the MALDI-IMS technique can be applied to clinical biopsy specimens or surgically resected tissues after neoadjuvant chemotherapy. In addition, the data obtained by MALDIIMS can

global distribution of drugs within tissue. However, its application has
been limited for a variety of reasons, including its limited resolution 7,8 .
Recent progress in MALDI-IMS analysis, including the new features of
our instrument, have achieved a MALDI-IMS resolution of 10 µm or
Conventional MALDI-IMS was expected to aid in the analysis of the
image of the same sample. In fact, we were able to distinguish the
less, which is advantageous for evaluating the drug distribution in
resolution also allows an IMS image to be overlaid on an optical
specific cells or areas of interest within tissues 9–12 . The improved
nerve component from the surrounding tissue and evaluate the

specific distribution of PTX in the region. Tissue samples should be frozen without liquid solution to avoid the diffusion or loss of the drug from the tissue to the solution. For efficient ionisation in the present study, the sample was coated with a sufficient quantity of matrix by spraying. 2,5-Dihydroxybenzoic acid (DHB) was selected as the matrix to facilitate the efficient ionization of the drug. We are now attempting to use several other matrix materials to enhance the sensitivity of our MALDI-IMS technique. Moreover, we used a combination of MS and MS/MS for the imaging analysis. In the MS analysis, accurate quantification of PTX was demonstrated in vivo. In the MS/MS

Discussion similar m/z.

selected as a PTX-specific fragment peak (Fig. 3c), was observed
optical microscopy (left) and by MS/MS analysis of PTX (m/z 607.19*) (right) in tumours treated with PTX (d) or NK105 (e) at 1 h
shown in (b). The fragment pattern from MS/MS analysis of the tumour tissue sample is shown in (c). (d) (e) Images obtained by
ɹɹ
at a higher level in the tumour tissue sample at 1 h after PTX
(a) The structure of PTX is shown. (b) (c) The PTX-specific MS/MS fragments at m/z 224.06, 547.17, 607.19, and 832.26 are
peripheral neural tissue at 30 min, 1 h, and 24 h after
injection than at 1 h after NK105 injection (Fig. 3d, e).

administration. The signals surrounding and inside the nerve were lower after NK105 injection than after PTX injection (Fig. 4b, c). LC-MS analysis of the neural samples revealed that the concentration of rPTX after NK105 injection was also lower than
Fig. 3. Validation of the PTX and NK105 distribution within the tumour tissues by MS/MS analysis.
that after PTX injection (Fig. 4d). (a) Mechanical sensory stress was assayed in an animal model of PTX-induced peripheral neuropathy. NK105, PTX, or saline was administered at 30 mg/kg on days 0, 2, 4, 7, 9, and 11. **P < 0.01 (PTX vs. NK105), ***P < 0.001 (saline vs. PTX). Bar = SD. (b) (c) PTX within neuronal tissue was imaged after PTX (b) or NK105 (c) administration at a dose of 50 mg/kg. The upper, middle, and lower columns show the optical images, a neuronal marker (sphingomyelin-specific signal of 851.6 m/z), and PTX (specific signal of m/z 892.3 [M + K]+ ), respectively. The neuronal area is delineated by a wh

global w430×h280 Validation of the PTX and NK105 distribution within tumour tissue by MS/MS analysis. Validation of the PTX content in each sample was performed in MS/MS mode. A structural diagram and the MS/MS fragmentation pattern (FP) of PTX are shown in Fig. 3a and b, respectively. According to the MS/MS-FP, m/z 607.19, which was after injection. Bar, 500 µm. Peripheral neurotoxicity and visualisation of the PTX and NK105 distribution by MS analysis. Next, a mechanical stress test that measured the degree of peripheral neurotoxicity demonstrated that the mice in the PTX treatment group exhibited a significantly stronger hypersensitive reaction to the mechanical stress test than those in the control and NK105 tre

New Technology 68