Technetium-99m labeled Ibuprofen: Development and biological evaluation using sterile inflammation induced animal models

In this study we are presenting the development of technetium-99m (99mTc) labeled ibuprofen for the imaging of aseptic inflammation. 99mTc-Ibuprofen complex was developed by optimizing the radiolabeling conditions such as reaction time, ligand and reducing agent concentration, pH, reaction time and temperature. Following the addition of 600 µg of ibuprofen, 4 µg of stannous chloride as reducing agent and 300 MBq 99mTc radioactivity; the pH of reaction mixture was adjusted to 11 and allowed to react for 15 min at room temperature. Chromatography analysis revealed > 94% 99mTc-ibuprofen complex formation with promising stability in saline and blood serum up to 6 h. Biodistribution study using normal and sterile inflammation induced mice indicated low accumulation of labeled compound in key body organs; however, kidneys (14.76 ± 0.87% ID/g organ) and bladder (31.6 ± 3.0% ID/g organ) showed comparatively higher radioactivity due to main excretory path. Inflamed to normal tissues ratio (T/NT), at 1 h post-injection, showed promising value (4.57 ± 0.56). The SPECT imaging of artificially inflammation induced rabbit model also verified the biodistribution results. In conclusion, radiochemical purity and biological evaluation of 99mTc-ibuprofen complex indicates the agent can be utilized for imaging of deep seated aseptic inflammation.