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Rashtriya College of Pharmacy Hatnoor, Kannad, Chhatrapti Sambhajinagar
In recent years, the development of novel drug delivery systems has gained immense attention in the pharmaceutical and biomedical fields. Among them, smart polymers, also referred to as stimuli- responsive polymers, have emerged as a revolutionary class of materials for controlled drug release. Unlike conventional polymers, which provide passive encapsulation and release of drugs, smart polymers are capable of responding to specific external or internal stimuli such as pH, temperature, light, enzymes, redox potential, or magnetic fields. This unique ability enables precise spatial and temporal control of drug release, thereby improving therapeutic efficacy, reducing side effects, and enhancing patient compliance. Despite significant progress, several challenges remain in the clinical translation of smart polymer- based drug delivery systems. Issues such as biocompatibility, biodegradability, large-scale production, reproducibility, and regulatory approval must be carefully addressed. Moreover, long-term safety and stability of these materials in biological systems need thorough investigation. Nevertheless, ongoing advances in polymer chemistry, nanotechnology, and biomedical engineering are continuously improving the design and functionality of smart polymers. Integration with emerging fields such as personalized medicine, targeted drug delivery, and nanotheranostics further enhances their potential.
Nanoparticles (NPs) have been successfully adopted in electronics, food and agriculture, biosensing, and some areas of nanomedicine; however, their translation to clinical oncology remains limited. Although nanomedicine-based drug delivery has been dominating the field of cancer research over the past decade, only a dozen US Food and Drug Administration (FDA)-approved NPs are currently available. As such, there is a growing need for novel NPs in oncology to improve drug delivery for cancer treatment, mainly through target-driven design. Currently, poor patient outcomes are attributed in part to the low stability, drug solubility and bioavailability, poor pharmacokinetic (PK) and pharmacodynamic (PD) parameters, a specific distribution, cytotoxicity, and chemo resistance that are characteristic of traditional chemotherapeutic agents. As a result, nanomedicine-based drug delivery has been of increasing research interest because NPs have been shown to substantially improve the therapeutic efficacy of chemotherapeutic agents by overcoming the various anatomical, physiological, chemical, and clinical barriers associated with intravenous drug administration However, the lack of efficacy in the clinic has made innovative NP-design and -delivery approaches increasingly important in the translation of these promising therapies from bench to bedside.
Smart Nanoparticles
NP drug-delivery systems that can release the drug in response to specific physiological triggers, at the appropriate time, and at the correct target site are referred to as smart NPs. For this review, smart NPs refer to those incorporating all three delivery strategies: passive, active, and stimuli-responsive targeting, as summarized. The enhanced permeability and retention (EPR) effect, or passive targeting, is the most basic targeting strategy employed by smart NPs. The EPR effect and its limitations have been reviewed extensively elsewhere. the EPR effect is a complex phenomenon dictated by the degree of leaky tumor vascularization and poor lymphatic draining that varies significantly between tumor types, anatomical sites, and patients. However, the high intestinal fluid pressure in tumors can prevent successful uptake and homogenous drug distribution. Long-circulating liposomes, polymers, and micelles are examples of NPs that take advantage of the leaky vasculature of tumors that ultimately allows for the entrapment and accumulation of NPs.
Shivaji Katade*, Ram Baban Ingle, Nayan Anil Sardar, Smart Polymers is Controlled Drug Release, Int. J. Sci. R. Tech., 2025, 2 (12), 201-210. https://doi.org/10.5281/zenodo.17928835
10.5281/zenodo.17928835