1. INTRODUCTION:

Nanotechnology has gained significant importance in pharmaceutical sciences due to its wide applications in diagnosis, treatment, and prevention of diseases. Nanoparticle-based drug delivery systems have revolutionized modern medicine by improving drug solubility, stability, bioavailability, and therapeutic efficiency. These systems enable drugs to reach specific target sites with controlled release, thereby reducing adverse effects and improving patient compliance.

1.1 What are Nanoparticles:

Nanoparticles are extremely small particles with sizes ranging from 1 to 100 nanometers. Due to their small size, they exhibit unique physical, chemical, and biological properties compared to larger particles. One of the major advantages of nanoparticles is their ability to penetrate cells and tissues and cross biological barriers such as the blood–brain barrier. In the pharmaceutical industry, nanoparticles are used as drug carriers to deliver therapeutic agents to the target site. This targeted delivery helps in increasing drug effectiveness while reducing side effects and toxicity.

1.2 Why are Nanoparticles Used in Drug Delivery:

Nanoparticles are highly effective in drug delivery systems due to their nanoscale size and large surface area. They improve the effectiveness of poorly water-soluble drugs such as paclitaxel. Nanoparticles can circulate easily in the bloodstream, provide prolonged drug action, and reduce systemic toxicity. They are suitable for delivering various drugs, including hydrophilic drugs, hydrophobic drugs, anticancer agents, proteins, peptides, and vaccines. Nanoparticles can cross cell membranes and biological barriers and selectively reach target cells while sparing normal tissues. They also protect drugs that are sensitive to gastric acid and body pH. Certain nanoparticles, such as gold nanoparticles, are used in both cancer diagnosis and therapy.

1.3 Purpose of the Review:

Nanoparticles have gained widespread attention due to their extensive applications in medicine and pharmacy. Numerous research and review articles have been published on nanoparticles, but many are complex and difficult to understand for students and early researchers. The purpose of this review is to collect, analyze, and present information from various published studies in a simple and systematic manner. This review aims to provide clear knowledge on the basic concepts, types, properties, preparation methods, applications, advantages, and limitations of nanoparticles, especially in pharmaceutical drug delivery systems.

1.4 Scope of the Study:

The scope of this review is to provide a simplified yet detailed overview of nanoparticle-based drug delivery systems. It focuses on information collected from recently published, high-quality, open-access research articles. The review covers different types of nanoparticles, their structure, composition, advantages, preparation methods, and applications. It also discusses advanced nanoparticle systems for improving site-specific drug delivery and therapeutic activity, along with their benefits and limitations.

2. Types of Nanoparticles Used in Drug Delivery:

Nanoparticles used in drug delivery systems are classified based on the materials used for their preparation. Each type has unique properties and applications depending on the nature of the drug and therapeutic requirements.

2.1 Polymeric Nanoparticles:

Polymeric nanoparticles are solid colloidal particles prepared using natural or synthetic polymers. Drugs may be dissolved, entrapped, or adsorbed onto the polymer matrix. These nanoparticles protect drugs from degradation and allow controlled and sustained drug release. Most polymers used are biodegradable and biocompatible.

Example: PLGA nanoparticles loaded with paclitaxel for cancer therapy.

2.2 Lipid-Based Nanoparticles:

Lipid-based nanoparticles are prepared using physiological lipids similar to biological membranes. They enhance drug solubility, stability, and bioavailability while reducing toxicity. These nanoparticles are widely used in cancer therapy, vaccine delivery, and targeted drug delivery.

Example: Lipid nanoparticles used in Pfizer and Moderna mRNA COVID-19 vaccines.

2.3 Solid Lipid Nanoparticles (SLNs):

SLNs are prepared using solid lipids that remain solid at room and body temperatures. They combine advantages of lipid and polymeric nanoparticles and provide controlled drug release and stability.

Examples: Ketoprofen SLNs, curcumin SLNs, clotrimazole SLNs, ibuprofen-loaded SLNs.

2.4 Nanostructured Lipid Carriers (NLCs):

NLCs are second-generation lipid nanoparticles composed of solid and liquid lipids. They allow higher drug loading and reduced drug leakage.

Examples: Ketoconazole-loaded NLCs, rifampicin-loaded NLCs.

2.5 Metal and Metal Oxide Nanoparticles:

Metal nanoparticles such as gold, silver, iron oxide, and zinc oxide show unique properties including antimicrobial, magnetic, and photothermal effects. They are used in diagnostics, imaging, and cancer therapy.

2.6 Dendrimers:

Dendrimers are highly branched nanostructures with high drug loading capacity and precise size control. They are mainly used in targeted drug delivery and gene therapy.

2.7 Nanogels:

Nanogels are nanosized hydrogel particles capable of absorbing large amounts of water. They provide controlled drug release and are used in transdermal, ocular, and gene delivery systems.

3. Basic Properties of Nanoparticles:

The performance of nanoparticles in drug delivery depends on their physical and chemical properties, which influence drug stability, release, and therapeutic effect.

3.1 Particle Size:

Particle size affects absorption, distribution, cellular uptake, and clearance. Smaller nanoparticles show better penetration, while larger ones may circulate longer.

3.2 Shape and Structure:

Nanoparticles may be spherical, rod-shaped, cubic, or irregular. Shape affects cellular interaction and circulation time. Spherical nanoparticles are most commonly used due to stability.

3.3 Surface Charge:

Surface charge influences stability and cellular uptake. Positively charged nanoparticles show higher uptake but increased toxicity, while neutral or negatively charged nanoparticles are generally safer.

3.4 Surface Modification:

Surface modification involves coating nanoparticles with polymers such as PEG or attaching ligands to improve circulation time, targeting ability, and biocompatibility.

3.5 Drug Loading Capacity:

Drug loading capacity refers to the amount of drug incorporated into nanoparticles. Higher drug loading improves therapeutic efficiency and reduces carrier requirement.

4. Methods of Preparation of Nanoparticles:

Common preparation methods include solvent evaporation, nanoprecipitation, emulsion-based methods, green synthesis, high-pressure homogenization, and ionic gelation. Selection depends on drug nature, material used, and desired particle characteristics.

5. Drug Delivery Mechanisms of Nanoparticles:

5.1 Passive Targeting:

Based on the enhanced permeability and retention (EPR) effect, mainly used in cancer therapy.

5.2 Active Targeting:

Involves ligand-mediated targeting using antibodies, peptides, or folic acid.

5.3 Controlled Release:

Provides sustained drug release through diffusion, degradation, or swelling.

5.4 Stimuli-Responsive Release:

Drug release triggered by pH, temperature, or enzymes.

6. Recent Advances in Nanoparticle Drug Delivery:

Recent developments include smart nanoparticles, surface-modified nanoparticles, biomimetic nanoparticles, gene and vaccine delivery systems, and integration of artificial intelligence and machine learning in nanomedicine.

7. Applications of Nanoparticle Drug Delivery:

Applications include cancer therapy, brain targeting, antiviral and vaccine delivery, wound healing, ocular drug delivery, and antimicrobial therapy.

8. Safety and Toxicity Issues:

Nanoparticles may cause cytotoxicity, immunotoxicity, genotoxicity, and organ-specific toxicity. Proper safety evaluation and regulatory guidelines are essential.

9. Challenges and Limitations:

Major challenges include manufacturing scale-up, stability issues, drug loading limitations, toxicity concerns, high cost, and regulatory barriers.

10. Future Prospects:

Future developments focus on personalized nanomedicine, advanced targeted delivery, gene editing applications, biodegradable nanoparticles, and AI-based formulation design.

11. CONCLUSION:

Nanoparticle-based drug delivery systems play an important role in modern pharmaceutical research by improving drug targeting, bioavailability, and therapeutic efficiency. Despite challenges such as toxicity, stability, and cost, continuous research and technological advancements are expected to enhance their safety and effectiveness. Nanoparticle drug delivery systems represent a promising and evolving area with great potential for future clinical applications.

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Received on 30.11.2025 Revised on 23.12.2025

Accepted on 09.01.2026 Published on 30.01.2026

Available online from February 05, 2026

Res. J. Pharma. Dosage Forms and Tech.2026; 18(1):73-76.

DOI: 10.52711/0975-4377.2026.00012

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