Synthesis, Characterization, and Biodistribution of Quantum Dot-Celecoxib Conjugate in Mouse Paw Edema Model

Increased risk of cardiovascular side effects has been reported with many of the drugs in the market, including nonsteroidal anti-inflammatory drugs (NSAIDs). Hence, it is critical to thoroughly evaluate the biodistribution and pharmacokinetic properties of the drugs. Presently nanotechnology in combination with noninvasive imaging techniques such as magnetic resonance imaging (MRI), computed axial tomography (CAT), and positron emission tomography (PET) provides a better estimate of the spatio-temporal distribution of therapeutic molecules. Optical imaging using quantum dot- (QD-) tagged biological macromolecules is emerging as a fast, economical, sensitive, and safer alternative for theranostic purposes. In the present study, we report the nanoconjugates of mercaptopropionic acid- (MPA-) capped CdTe quantum dots (QDs) and Celecoxib for bio-imaging in carrageenan-induced mouse paw edema model of inflammation. QD-Celecoxib conjugates were characterized by fluorescence, FT-IR, NMR, and zeta-potential studies. In vivo imaging of QD-Celecoxib conjugates showed clear localization in the inflamed tissue of mouse paw within 3 h, with a gradual increase reaching a maximum and a later decline. This decrease of fluorescence in the paw region is followed by an increase in urinary bladder region, suggesting the possible excretion of QD-drug conjugates from mice within 24 h.