1. INTRODUCTION:

Drug delivery systems have evolved tremendously in recent decades with the aim of improving therapeutic efficacy and minimizing side effects. Conventional dosage forms often suffer from poor solubility, rapid degradation, low bioavailability, and non-specific drug distribution. Nanotechnology has provided innovative approaches to overcome these limitations through the development of nanoscale carriers.

Nanosponges are one such advanced nanocarrier system characterized by a highly cross-linked porous structure capable of entrapping active pharmaceutical ingredients. These tiny sponge-like particles can transport drugs to specific sites and release them in a controlled manner over prolonged periods. Their nanosized dimensions improve penetration and interaction with biological membranes.

Nanosponges are especially useful for drugs with poor aqueous solubility. Encapsulation within nanosponges enhances dissolution rate, stability, and bioavailability while reducing irritation and toxicity. Due to these properties, nanosponges have become promising carriers in oral, topical, parenteral, and targeted drug delivery systems^1-3.

2. History and Development of Nanosponges:

The concept of nanosponges was introduced as an extension of cyclodextrin chemistry to improve drug encapsulation efficiency. Initially, cyclodextrins were used to enhance solubility of poorly soluble drugs; however, limitations such as low complexation efficiency led researchers to develop cross-linked porous structures called nanosponges.

Over the years, nanosponge technology has advanced significantly with the introduction of biodegradable polymers, environmentally friendly synthesis techniques, and stimuli-responsive systems. Current research focuses on multifunctional nanosponges for cancer targeting, gene delivery, and personalized medicine applications^4-5.

3. Structure and Composition:

Nanosponges possess a three-dimensional porous network formed by cross-linking polymers with suitable cross-linkers. The porous cavities within the structure act as reservoirs for drug molecules.

Main components include:

· Polymers

· Cross-linking agents

· Drug molecules

· Stabilizers

Commonly used polymers:

· β-cyclodextrin

· Ethyl cellulose

· Polyvinyl alcohol

Common cross-linkers:

· Diphenyl carbonate

· Carbonyl compounds

· Pyromellitic dianhydride

The size of nanosponges generally ranges from 1nm to 1 μm depending on preparation conditions.

4. Mechanism of Drug Release:

Drug molecules are entrapped within nanosponge cavities through adsorption or encapsulation mechanisms. After administration, the drug is slowly released from the porous matrix by diffusion, degradation, or environmental triggers such as pH and temperature changes.

The controlled release pattern helps maintain therapeutic concentration for extended periods and reduces dosing frequency.

Advantages of Nanosponges:

· Improved solubility of poorly soluble drugs

· Controlled and prolonged drug release

· Reduced irritation and toxicity

· Better stability of drugs

· Site-specific targeting

· Enhanced patient compliance

· Improved bioavailability

· Easy formulation into creams, gels, capsules, and tablets

· High drug-loading efficiency

· Better therapeutic response

Disadvantages of Nanosponges:

Despite several advantages, nanosponges possess certain limitations:

· Complex manufacturing procedures

· High production cost

· Risk of residual solvent toxicity

· Limited loading for large molecules

· Requirement of specialized instruments

Applications of Nanosponges:⁶

a) Acne Treatment:

Nanosponges are extensively used for topical anti-acne drugs such as benzoyl peroxide and adapalene. Controlled release minimizes skin irritation and dryness.

b) Cancer Therapy:

Nanosponges improve targeting of anticancer drugs and reduce systemic toxicity. They increase accumulation of drugs at tumor sites.

c) Antifungal Drug Delivery:

Antifungal drugs like fluconazole and ketoconazole show improved penetration and therapeutic action when loaded into nanosponges.

d) Oral Drug Delivery:

Nanosponges improve dissolution and gastrointestinal absorption of poorly soluble drugs.

e) Topical Delivery:

Topical formulations containing nanosponges exhibit prolonged retention on skin and enhanced penetration.

f) Protein and Peptide Delivery:

Nanosponges protect proteins from degradation and provide sustained release.

g) Cosmetic Applications:

Nanosponges are used in cosmetics for controlled release of fragrances, vitamins, and sunscreens.

Safety and Toxicity Aspects:

Safety evaluation is an important aspect of nanosponge formulations. Most cyclodextrin-based nanosponges are biocompatible and non-irritant. However, toxicity studies are necessary to evaluate residual solvents, polymer compatibility, and long-term effects.

In-vitro cytotoxicity studies and animal studies are commonly performed to assess safety profiles.

Recent Advances:

Recent developments include smart nanosponges capable of responding to stimuli such as pH, enzymes, and temperature. Researchers are also exploring biodegradable nanosponges and green synthesis methods.

Advanced nanosponge systems are under investigation for gene delivery, vaccine delivery, photodynamic therapy, and theranostic applications^7-8.

5. Methods of Preparation:

5.1 Solvent Method: Polymers and cross-linkers are dissolved in suitable solvents and reacted under controlled conditions.

5.2 Ultrasound-Assisted Method:

Ultrasonication produces uniform nanosponges with improved particle size distribution.

5.3 Emulsion Solvent Diffusion Method:

Drug-polymer solution is dispersed into aqueous phase followed by solvent evaporation.

5.4 Melt Method:

The polymer and cross-linker are heated without using solvents to produce porous structures.

5.5 Microwave-Assisted Synthesis:

Microwave irradiation accelerates cross-linking reactions and reduces processing time.

6. Evaluation and Characterization:^9-10

Several evaluation parameters are used to study nanosponge quality and performance.

· Particle size analysis

· Surface morphology using SEM and TEM

· Zeta potential determination

· Entrapment efficiency

· Drug loading capacity

· FTIR spectroscopy

· Differential scanning calorimetry

· Powder X-ray diffraction

· In-vitro drug release studies

· Stability studies

These studies ensure proper formulation development and therapeutic effectiveness.

7. Future Prospects:

Nanosponges have tremendous future potential in personalized medicine and targeted therapy. Their ability to encapsulate diverse molecules and provide controlled release makes them highly versatile.
Integration of nanosponges with artificial intelligence, 3D printing, and advanced biomaterials may further revolutionize pharmaceutical drug delivery systems.

8. CONCLUSION:

Nanosponges are innovative nanoscale carriers with significant potential in targeted and controlled drug delivery. Their porous architecture, high drug-loading capacity, and ability to improve solubility and stability make them promising systems in modern pharmaceutics. Applications in acne therapy, cancer treatment, antifungal delivery, and cosmetics demonstrate their broad utility. Continuous research and technological advancements are expected to enhance the clinical applicability and commercialization of nanosponge-based formulations in the future.

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Received on 02.05.2026 Revised on 25.05.2026

Accepted on 13.06.2026 Published on 07.07.2026

Available online from July 10, 2026

Res. J. Pharma. Dosage Forms and Tech.2026; 18(3):252-254.

DOI: 10.52711/0975-4377.2026.00036

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