Nanotechnology-Enabled Thienopyrimidines: A Frontier in Targeted Drug Delivery

Thienopyrimidines are a prominent class of heterocyclic compounds structurally related to purines, which enables them to interact effectively with nucleic acid-binding proteins, kinases, and enzymes. Owing to these interactions, they have emerged as promising scaffolds with wide-ranging pharmacological activities, including anticancer, antimicrobial, antiviral, and anti-inflammatory effects. Despite their therapeutic relevance, many thienopyrimidine derivatives exhibit limitations such as poor aqueous solubility, low oral bioavailability, rapid systemic clearance, and potential off-target toxicity, which restrict their clinical success. Recent advancements in nanotechnology have created new opportunities to address these challenges. Nanocarrier-based formulations, including polymeric nanoparticles, solid lipid nanoparticles, liposomes, dendrimers, metallic nanostructures, and hybrid nanosystems, have demonstrated the ability to enhance solubility, improve pharmacokinetic performance, and enable controlled or stimuli-responsive drug release. Incorporating targeting ligands and multifunctional theragnostic elements further aligns thienopyrimidine-loaded nanoparticles with the growing paradigm of precision and personalized medicine. In oncology, these systems offer site-specific tumor accumulation and reduced systemic toxicity, while in infectious and inflammatory disorders, they provide sustained efficacy and reduced resistance development. This review highlights the most recent progress in the design and biomedical applications of thienopyrimidine-based nano formulations. It also discusses the translational challenges, including large-scale manufacturing, regulatory considerations, long-term safety, and clinical validation.