Yttrium-90 and Rhenium-188 Radiopharmaceuticals for Radionuclide Therapy

(b)
Quality control of 188 Re(V) DMSA
(i) RCP:
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TLC was performed using SG strips (TLC, Kieselgel 60 F 254 , Merck)
with different systems: (i) N-butanol:acetic acid:water (3:2:3),
(ii) N-propanol:acetic acid:water (4:1:1), (iii) N-propanol:acetic acid (3:1)
and (iv) N-propanol:acetic acid:water (4:1:3). The ITLC chromatograms
were analysed by cutting the strips into segments of 1 cm and, then
measuring the radioactivity in a well type NaI(Tl) γ counter (Wallac Comp
Gamma Counter LKB).
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The labelled samples were analysed using RP HPLC (column
Hamilton PRP-1, 250 mm, with a gradient elution system comprising
0.1% trifluoroacetic acid in water (solvent A) and 0.1% trifluoroacetic
acid in ACN (solvent B)). The flow rate was adjusted to 2 mL/min and the
gradient was as follows: 0–1 min, 0% B; 1–8 min, 0–50% B; 8–15 min,
50% B; 15–19 min, 50–0% B; 19–24 min, 0% B. The eluate was continuously
analysed serially using UV–visible absorbance and γ ray detection.
(ii) In vitro stability:
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In vitro stability of 188 Re(V) DMSA was determined under optimal
conditions for 4 h at room temperature using TLC and HPLC.
In vivo studies:
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Biodistribution studies of 188 Re(V) DMSA were performed in male Wistar
rats. A volume of 0.2 mL (21.5 MBq) was injected through the tail vein and
rats were sacrificed at 1 h p.i. Five rats were used for each preparation. The
tissues and organs were excised, rinsed with saline, weighed and counted.
Distribution of the activity in different organs was calculated as the
percentage of injected dose per gram, as well as the percentage of injected
dose per organ.
(iii) Human studies with 188 Re(V) DMSA:
— — Therapeutic administration was carried out according to the protocol
developed by V. Papantoniou from the Nuclear Medicine Department of
Alexandra University Hospital (Greece). Before administration of 188 Re(V)
DMSA, two patients were subjected to whole body scintigraphy and
scintimammography for localization of primary and metastatic lesions.
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