Editorial: Progress and Perspectives in Advanced Drug Delivery Technologies: Novel Drug Delivery Systems

INNOVATIONS IN CONTROLLED AND TARGETED DRUG DELIVERY SYSTEMS Despite remarkable advances in pharmaceutical sciences, the clinical performance of many drugs remains constrained by suboptimal delivery strategies. Conventional dosage forms frequently release therapeutic agents at rates that are either excessive or insufficient, compromising both efficacy and safety. Immediate adverse reactions and long-term toxicities often arise not solely from the drug itself, but from the manner in which it is administered (1). Thus, drug delivery is no longer a passive component of therapy; it is a determinant of therapeutic success. The distribution of a drug across tissues and receptor sites directly influences its therapeutic index and overall clinical outcome. Recognizing this, researchers have increasingly shifted their focus to controlled, targeted drug delivery systems designed to optimize pharmacokinetics and pharmacodynamics while minimizing systemic exposure (2,3). As illustrated in Figure1a, innovative carrier platforms have transformed traditional administration approaches, enhancing both drug stability and therapeutic precision. Modern delivery systems—including liposomes, nanoparticles, micelles, microspheres, and hydrogels—aim to improve bioavailability by directing the drug moiety specifically to its site of action. Targeted delivery fundamentally relies on two coordinated processes: accurate target recognition and effective pharmacological action at the diseased site (4). The overarching objective is clear: to maximize therapeutic activity while reducing off-target toxicity, thereby improving patient outcomes and safety profiles. In contemporary pharmaceutical development, innovation is no longer limited to discovering new molecules; it increasingly lies in redefining how those molecules are delivered (5). ACTIVE AND PASSIVE TARGETING STRATEGIES The development of targeted drug delivery has fundamentally reshaped the therapeutic landscape. Active targeting involves functionalizing carrier systems with specific ligands that selectively recognize pathological sites, enhancing both accumulation and cellular uptake (Figure 1b). This approach has demonstrated significant promise in hematological malignancies such as leukemia and lymphomas, where receptor overexpression can be exploited to improve therapeutic precision (4,6). By directing drugs to their intended targets, active strategies minimize systemic exposure and reduce off-target toxicity. In contrast, passive targeting relies on the inherent pathophysiological characteristics of diseased tissues. Nanocarriers preferentially accumulate at sites such as the tumor interstitium due to the enhanced permeability and retention (EPR) effect, which arises from leaky vasculature and impaired lymphatic drainage (6,7). While less selective than ligand-mediated approaches, passive targeting remains foundational in nanomedicine and has guided the design of numerous clinically approved nanoformulations.