Quercetin-conjugated nanoparticles enhance drug delivery to dental tissues: an experimental study in rats.

This study investigated the potential of quercetin-conjugated superparamagnetic iron oxide nanoparticles (QC-SPIONs) as novel drug delivery systems, with a specific focus on their distribution in the dental tissues of rats. Quercetin, an antioxidant flavonoid, is limited due to its poor solubility and bioavailability, which restricts its therapeutic efficacy. To address this, 42 male Wistar rats were divided into seven groups and subjected to either oral or intraperitoneal administration of free quercetin, SPION, or QC-SPION over 35 days. The presence of iron and quercetin in the tooth tissue was assessed via inductively coupled plasma (ICP) spectroscopy and high-performance liquid chromatography (HPLC), respectively. Biochemical markers of the liver and kidney function were assessed to evaluate systemic safety, while real-time PCR was performed to assess the expression levels of apoptotic genes mRNA (Bax and Bcl-2) in tooth pulp. The results demonstrated that intraperitoneal administration of QC-SPIONs significantly enhanced quercetin and iron concentrations in dental tissues compared to oral administration, indicating superior tissue penetration. Importantly, no adverse effects on liver (AST, ALT, ALP, GGT, LDH) or kidney (GGT, LDH) function were observed, and there were no significant changes in apoptotic gene expression, suggesting the absence of systemic toxicity or cellular apoptosis. These findings highlight the potential of QC-SPIONs as a safe and effective strategy for targeted oral drug delivery, offering improved quercetin biodistribution in dental tissues without inducing adverse effects. This approach could pave the way for innovative treatments addressing oxidative stress-related oral diseases.