Nanotechnology for cancer is no longer just a topic of academic research. For more than twenty years, some nanoparticle-based anticancer drugs have already been on the market and used in clinical practice. For professionals developing pharmaceutical formulations, this represents a concrete field of application, not merely a promise for the future.

In this article, we look at the types of pharmaceutical nanoparticles currently used in oncology, which drugs have already been approved, and which limitations researchers are still working to overcome.

The Problem with Traditional Chemotherapy and Why a Different Approach Is Needed

Conventional chemotherapy drugs have a fundamental limitation: they do not distinguish between cancer cells and healthy cells. The drug circulates through the bloodstream and indiscriminately affects tissues with a high rate of cell proliferation, causing the typical side effects of chemotherapy, ranging from cardiac toxicity to bone marrow toxicity.

There is also a solubility issue. Many anticancer active pharmaceutical ingredients are poorly soluble in water and therefore require solvents such as Cremophor for intravenous administration. Cremophor itself can cause hypersensitivity reactions in patients.

Pharmaceutical nanoparticles were developed to address both problems: increasing drug concentration in tumor tissue while reducing toxicity to healthy tissues.

Pharmaceutical Nanoparticles: The Main Types Used in Oncology

There is no single type of pharmaceutical nanoparticle. Research has developed several structures, each with different characteristics in terms of size, stability, and drug-loading capacity.

Liposomes

Liposomes are spherical vesicles made of a lipid bilayer similar to the membrane of cells. They encapsulate the active ingredient, protect it from degradation, and gradually release it once the target tissue has been reached. They are the most established category of pharmaceutical nanoparticles in oncology.

Polymer-Drug Conjugates

In this case, the active ingredient is not encapsulated but chemically bound to a polymer, often with dimensions exceeding 100 nanometers. This approach makes it possible to control drug release over time and reduce systemic toxicity.

Protein-Bound Nanoparticles

The active ingredient is conjugated to a protein, typically albumin. This system avoids the use of problematic solvents such as Cremophor and reduces the risk of hypersensitivity reactions, while also allowing shorter infusion times.

Dendrimers

Dendrimers are branched macromolecules with a symmetrical tree-like structure and very small dimensions, typically between 1 and 10 nanometers. Unlike liposomes, they do not encapsulate the drug. Instead, they carry it on their surface using their numerous available branches. They are chemically stable and have low cytotoxicity.

Nanoparticle-Based Drugs Already Used in Clinical Practice

Several nanoparticle-based oncology drugs have already been approved and prescribed for years. Some of the best known include:

• Liposomal doxorubicin (Doxil, Caelyx, Myocet, DaunoXome): an encapsulated form of doxorubicin, one of the most widely used chemotherapy drugs, with a lower cardiac toxicity profile than the conventional formulation.
• Liposomal irinotecan (Onivyde): approved for pancreatic cancer, with its use extended to first-line treatment in 2024.
• Albumin-bound paclitaxel (Abraxane): used for metastatic breast cancer. It does not contain Cremophor and, unlike conventional paclitaxel formulations, does not require premedication with corticosteroids or antihistamines.

These are complemented by pegylated formulations such as Pegintron, Somavert, Pegasys, and Cimzia, in which the active ingredient is bound to polyethylene glycol (PEG) to increase its circulation time in the bloodstream. Nanoparticle-delivered drugs have been available on the European market for approximately twenty years.

How Nanoparticles Reach Tumors: Passive Delivery and Active Targeting

Nanoparticles can reach tumor tissue through two different mechanisms.

The first is passive delivery. The blood vessels supplying a tumor are often more permeable and disorganized than those found in healthy tissues. Because of their size, nanoparticles can therefore accumulate more easily in the affected area.

The second is active targeting. The surface of the nanoparticle is modified with molecules capable of binding to specific receptors expressed by cancer cells. One example is the use of hyaluronic acid-based nanoparticles designed to bind to the CD44 receptor, which is overexpressed in several types of cancer. This approach aims to make drug delivery more selective than passive accumulation alone.

Current Limitations: Why Selectivity Remains an Open Challenge

Despite the progress made, the selectivity of nanoparticles is still not optimal and remains one of the main priorities of oncology research. Not all nanoparticles reach the tumor in the expected quantities, and part of the administered dose is still distributed to other tissues.

Several research groups in Italy and internationally are working on new generations of nanocarriers designed for aggressive and metastatic cancers. These include nanoparticles capable of delivering nucleic acid-based therapies into cells more selectively. Some of these systems have already received orphan drug approval for rare genetic disorders, indicating how regulatory pathways are gradually adapting to these technologies.

From Research to Formulation: The Role of Encapsulation Systems

The transition from a promising active ingredient to a drug that can actually be administered depends largely on how the nanoparticle is formulated. Key factors include choosing the appropriate encapsulating material, ensuring controlled release, and maintaining product stability over time.

These are the same variables explored in our article on medical nanotechnology and lipid nanoparticles, where encapsulation is applied to mRNA vaccines rather than chemotherapy drugs, but the underlying technical principles are very similar.

Nanomnia works on precisely these types of challenges on behalf of its clients. Starting from the active ingredient provided by the client, the company evaluates formulation objectives such as increased bioavailability, resistance to environmental factors, and long-term stability. It then develops the most suitable encapsulated formulation and tests it in vitro before moving, when required, to testing under real-world conditions.

Material Biocompatibility: An Increasingly Important Variable

One aspect that is often underestimated in the development of pharmaceutical nanoparticles is the nature of the encapsulating material. Some systems are based on synthetic polymers, while others use fully biocompatible and biodegradable materials. These choices can have different implications for both patient safety and the environmental sustainability of the production process.

Nanomnia develops its encapsulated formulations exclusively using biocompatible and biodegradable materials such as polysaccharides, lipids, proteins, and natural resins. This approach makes it possible to achieve the same controlled-release and active ingredient protection performance associated with pharmaceutical nanoparticles, without the residues linked to synthetic materials.

Frequently Asked Questions About Nanotechnology for Cancer