Drug delivery: What it is and how to achieve it naturally

In recent decades, research has focused on the development of nanotechnology, particularly for use in the field of drug delivery.

This represents a significant opportunity, not only for the future but also for the improvement of numerous processes we utilize every day.

Let’s take a look at what lies behind drug delivery.

What are the applications of drug delivery?

Drug delivery is the conveyance of a substance with precision toward a zone, tissue, or cell, where its controlled release ensures the highest efficiency. This is a truly targeted action that can bring notable advantages to many different sectors.

Drug delivery in pharmaceuticals

Application in the pharmacological field allows a molecule to be transported within our body, reaching a target tissue selectively and being released in a controlled manner.

This methodology makes it possible to decrease the doses of the administered drug, consequently reducing potential side effects and making it more bioavailable.

Cancer therapy and diagnostic imaging are among the primary applications where drug delivery can offer enormous benefits. In the former, it reduces the unwanted effects of chemotherapy while increasing treatment efficacy; in the latter, the specific delivery of contrast agents allows for more defined and precise diagnostics.

Drug delivery and agriculture

In recent years, the need to reduce the use of agrochemicals has emerged due to their high toxicity to humans, who may come into contact with them by consuming food contaminated with residues.

The environment itself suffers from this indiscriminate use of chemicals in agriculture, as evidenced by the mass die-off of pollinating insects and the pollution of groundwater.

Nano- and microparticles produced with biodegradable polymers can encapsulate agrochemicals, releasing them in a controlled manner to increase treatment efficacy while reducing dosages.

The biopolymers used in drug delivery also meet the need to eliminate microplastics present in current commercial agrochemicals, making the entire delivery process absolutely natural.

As in the medical field, encapsulation in agriculture involves using biopolymers specific to the end goal of the treatment. For example, if the encapsulated molecule must act on the leaf surface, the polymers must ensure a strong and stable interaction with the cuticle; however, if the molecule must enter the leaf, the size of the nanoparticle and its interaction with the stomata must be modulated.

How to achieve effective and safe drug delivery?

To ensure that drug delivery is effective, safe, and biocompatible, research has focused on the study and use of biopolymers.

Some natural polymers can be directly extracted and purified from plants, microorganisms, algae, or fungi, while others can be synthesized from bio-derived monomers.

Their chemical-physical characteristics are decisive in obtaining nano- and microparticles capable of encapsulating various types of molecules, such as inorganic salts, nucleic acids, proteins, and synthetic molecules.

Furthermore, the surface of the particles must be suitable for the physiological or plant environment, hosting molecular signals that direct the particle only to the target tissue. Only then should the biopolymers break down, releasing their content at a calibrated speed.

What characteristics make natural polymers suitable for drug delivery?

Not all biopolymers are ideal for drug delivery. For optimal use in a delivery process, a natural polymer must be:

Biodegradable: It must be able to be disassembled into its basic molecules so that it can be naturally reused.
Non-toxic: It must not act chemically on the human or animal organism in a way that causes intoxication.
Safe: It must present no dangerous side effects, inflammation, or immune response.
Available: It must be easily obtainable in all parts of the world and immediately processable.
Economical: It must be inexpensive and simple to source in large quantities.

Drug delivery: Which biopolymers are most suitable?

In drug delivery, the choice of natural polymer depends on the final goal. The specific characteristics and properties of each biopolymer make it advantageous in some cases and less effective in others. Let’s look at some practical examples.

Chitosan

This is a polymer derived from the deacetylation of chitin, a natural biopolymer obtained from the shells of crustaceans. It is biocompatible, biodegradable, and non-toxic.

Its structure has been used for multiple chemical derivatizations to give it optimal characteristics for various types of encapsulation.

Its mucoadhesive advantage makes it an excellent candidate for delivery in the oropharyngeal cavity, while its degradability by microflora makes it suitable for delivery in organs like the intestine.

In medicine, it is useful for encapsulating insulin to increase its bioavailability and subsequent intestinal absorption. In the agritech sector, it is used to coat nano-microparticles that interact with the cuticle, releasing the encapsulated molecule on the leaf surface and preventing it from being washed away by rain. Its chemical characteristics also make it suitable for encapsulating viral vectors for cutting-edge gene therapies and advanced studies in plant physiology.

Alginate

Alginate is a natural polysaccharide extracted from brown algae, but it can also be purified from bacterial cultures.

Its pH sensitivity makes it an ideal polymer for protecting encapsulated molecules in acidic environments like the stomach and releasing them in more basic environments like the intestinal tract. Thus, gastro-irritant molecules can be encapsulated for more effective absorption in the intestine.

The ability to produce very stable microparticles also makes it suitable for the encapsulation of agrochemicals or microelements to be released in a controlled manner into the soil, ensuring a long-lasting effect.

Furthermore, studies for more advanced nanotechnology applications use alginate in association with proteins for the subcutaneous delivery of vaccines.

PLGA

Poly(lactic-co-glycolic acid), or PLGA, is a synthetic copolymer approved by the FDA (Food and Drug Administration).

It is particularly used for creating biocompatible and biodegradable nanoparticles in the pharmacological field.

Its great advantage lies in its ability to encapsulate hydrophobic molecules, which would otherwise struggle to circulate physiologically in our body, especially in effective doses.

Signal molecules can be easily attached to the surface of these nanoparticles to perform specific targeting toward tumors in different tissues. Once the encapsulated molecules are released, the PLGA degrades into harmless water and $CO_2$ molecules, which are naturally eliminated by the body.

Encapsulable therapeutic agents in PLGA nanoparticles include chemotherapeutics, antibiotics, anti-inflammatories, antioxidants, and proteins.

At Nanomnia, we have always used biocompatible and biodegradable polymers across all fields of intervention—from pharmacology and cosmetics to agrifood. The core idea is that drug delivery should be effective without leaving residues.

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