Ngozi Chukwu*
Department of Pharmaceutics and Drug Delivery, Afe Babalola University, Nigeria
Received: 2-Jun-2025, Manuscript No. dd-25-171111; Editor Assigned: 4-Jun-2025, Pre QC No. dd-25-171111; Reviewed: 18-Jun-2025, QC No. dd-25-171111; Revised: 23-Jun-2025, Manuscript No. dd-25-171111; Published: 30-Jun-2025, DOI: 10.4172/resrevdrugdeliv.9.2.005
Citation: Ngozi Chukwu, mRNA Drug Delivery: Unlocking a New Era in Medicine. Res Rev Drug Deliv. 2025;9.005.
Copyright: © 2025 Ngozi Chukwu, this is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and sources are credited.
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Stimuli-responsive drug delivery systems, also known as “smart drug delivery systems,” have emerged as an advanced approach to improve therapeutic efficacy and minimize side effects. Unlike conventional drug delivery, which releases drugs at a fixed rate regardless of physiological conditions, stimuli-responsive systems can respond to specific internal or external triggers to release their payload in a controlled manner. These triggers may include pH, temperature, enzymes, redox conditions, light, magnetic fields, or ultrasound [1]. By providing precise spatial and temporal control over drug release, these systems offer significant advantages in treating complex diseases such as cancer, diabetes, infections, and inflammatory disorders.
Stimuli-responsive systems can be broadly categorized based on the type of stimulus they respond to. Physiological stimuli, such as pH, temperature, or enzymatic activity, exploit the differences between healthy and diseased tissues. For example, tumor tissues often exhibit slightly acidic pH compared to normal tissues [2]. pH-sensitive nanoparticles or hydrogels can selectively release chemotherapeutic agents in the acidic tumor microenvironment, reducing systemic toxicity. Similarly, temperature-responsive polymers, such as poly(N-isopropylacrylamide) (PNIPAM), can release drugs at higher temperatures associated with inflamed or cancerous tissues [3].
Enzyme-responsive delivery systems are designed to respond to overexpressed enzymes in specific disease states. For instance, matrix metalloproteinases (MMPs) are upregulated in cancer and inflammatory diseases, and drug carriers can be engineered to degrade in the presence of these enzymes, ensuring site-specific drug release. Redox-responsive systems utilize the higher concentrations of reducing agents, such as glutathione, in cancer cells to trigger drug release, further enhancing targeting precision [4].
External stimuli, including light, ultrasound, and magnetic fields, provide additional control over drug release. Light-responsive systems can release drugs upon exposure to specific wavelengths, enabling on-demand therapy. Magnetic nanoparticles can be guided to target tissues using an external magnetic field, with drug release triggered by magnetic hyperthermia. Similarly, ultrasound-responsive carriers can deliver drugs locally and non-invasively, offering precise control in both space and time.
The advantages of stimuli-responsive systems extend beyond targeting. They improve drug solubility, stability, and circulation time. These systems are particularly valuable for delivering biologics such as peptides, proteins, and nucleic acids, which are otherwise prone to degradation. Additionally, smart carriers can combine diagnostic and therapeutic functions (theranostics), allowing real-time monitoring of disease progression and therapeutic response [5].
Stimuli-responsive drug delivery represents a paradigm shift in precision medicine, offering smart, controlled, and targeted therapeutic interventions. By responding to internal or external cues, these systems enhance drug efficacy, reduce side effects, and enable personalized treatment strategies. With advances in nanotechnology, polymer chemistry, and biomedical engineering, stimuli-responsive systems are increasingly translating from research to clinical applications, particularly in oncology, infectious diseases, and chronic disorders. While challenges related to biocompatibility, scalability, and regulation persist, the future of smart drug delivery promises safer, more efficient, and highly adaptable therapeutic solutions that align with the principles of modern, patient-centered medicine [6].
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