Lipid spheres navigating a cellular landscape, symbolizing drug delivery.

Cellular Defense: How Drug Delivery Systems Impact Cell Health

Nico Varela in Health & Wellness June 2025 • 4 min read.

"A Closer Look at the Cytotoxicity of Lipid-Based Drug Carriers: Emulsions, Liposomes, and Lecithin Dispersions"

In the realm of pharmaceutical technology, surfactants play a pivotal role. They act as emulsifiers, solubilizers, suspension stabilizers, and wetting agents across various formulations. However, safety considerations narrow the field to only a few surface-active agents approved for parenteral routes. Among naturally occurring surfactants, phospholipids, either alone or in combination with bile salts, stand out due to their significant importance.

Lecithin, commonly extracted from egg yolk or soya, is a complex mixture of various phospholipids. Its main component is phosphatidylcholine (PC). It's a key player in colloidal drug delivery systems, including intravenous fat emulsions, liposomes, and newly developed aqueous lecithin dispersions (WLDs). These systems are crucial for delivering drugs effectively and safely.

This article delves into the in vitro cytotoxicity of different phospholipid-based parenteral drug delivery systems. It will cover emulsions, liposomes, and aqueous lecithin dispersions (WLDs). By examining how these systems interact with cells, the aim is to provide insights into designing safer and more effective drug carriers. The research presented here seeks to identify the factors influencing cytotoxicity. The goal is to compare the safety profiles of these different delivery systems.

How Safe Are Common Drug Delivery Systems?

Lipid spheres navigating a cellular landscape, symbolizing drug delivery.

Lecithin phospholipids have been used extensively for over 50 years in creating submicron emulsions. These emulsions serve as carriers for fat-soluble vitamins, diazepam and propofol. The focus is to determine the influence of phospholipid type and chemical structure on the properties and stability of parenteral emulsions. Some suggest that combining natural phospholipids with synthetic surfactants like polysorbate or poloxamer could enhance emulsion stability.

Cytotoxicity experiments form a critical part of preclinical studies in new drug delivery system (DDS) development. The MTT assay is a common test for cytotoxicity studies. Other tests include lactate dehydrogenase (LDH) release assay, water-soluble tetrazolium (WST), and neutral red assays. It’s important to note that lipids or liposome particles can interfere with the MTT test, affecting results.

The study examined seven different DDSs (E, E-HS, E-P80, WLD, WLD-PCB, L, L-Ch).
Cytotoxic activity was tested in vitro on human embryonic kidney 293 (HEK-293) cells.
Cytotoxic activity was tested in vitro on human promyelocytic leukaemia (HL-60) cells.
Three tests were used: MTT assay, flow cytometry, real-time monitoring of cell proliferation.

The study aimed to identify factors influencing the cytotoxicity of parenteral carriers. It considered formulations with phospholipids alone or combined with synthetic surfactants. By comparing the safety of different dispersions, researchers hoped to refine future drug delivery methods.

The Future of Drug Delivery: Balancing Safety and Effectiveness

The study's results indicated that the type and concentration of surfactants, along with the size of lipid nanoparticles, can influence cytotoxic effects. While the overall cytotoxicity was low, it was more pronounced with specific formulations (E-P80, WLD, L-Ch) at higher concentrations.

It is important to dilute the drug before application. Such concentrated dispersions aren't used directly. They must be diluted for intravenous infusion. This ensures the drug is administered safely and effectively.

The research concludes that all prepared dispersions were biocompatible in vitro. They can be considered safe carriers for parenteral applications. Further research is needed to fully understand long-term effects and optimize these delivery systems for clinical use. The goal is to minimize toxicity while maximizing therapeutic benefits.

About this Article -

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This article is based on research published under:

DOI-LINK: 10.1016/j.ejps.2018.10.018, Alternate LINK

Title: Comparison Of The In Vitro Cytotoxicity Among Phospholipid-Based Parenteral Drug Delivery Systems: Emulsions, Liposomes And Aqueous Lecithin Dispersions (Wlds)

Subject: Pharmaceutical Science

Journal: European Journal of Pharmaceutical Sciences

Publisher: Elsevier BV

Authors: Marcin Płaczek, Dorota Wątróbska-Świetlikowska, Justyna Stefanowicz-Hajduk, Markus Drechsler, Jadwiga Renata Ochocka, Małgorzata Sznitowska

Published: 2019-01-01

Everything You Need To Know

What role do surfactants play in drug delivery?

Surfactants are essential in pharmaceutical technology, acting as emulsifiers, solubilizers, suspension stabilizers, and wetting agents. However, only a select few, approved for parenteral routes, are considered safe. Phospholipids, like Lecithin, are often used. Lecithin is commonly extracted from egg yolk or soya, is a complex mixture of various phospholipids. Its main component is phosphatidylcholine (PC). They are critical in creating drug delivery systems. Their significance lies in their ability to help the drug mix in the body, remain stable, and be absorbed effectively. The challenge is balancing their effectiveness with their potential for toxicity.

What are the main types of drug delivery systems that use Lecithin?

Lecithin is a key player in colloidal drug delivery systems. These include intravenous fat emulsions, liposomes, and aqueous lecithin dispersions (WLDs). They are used to deliver drugs effectively and safely. Lecithin, is a complex mixture of various phospholipids. Its main component is phosphatidylcholine (PC). They are used as carriers for fat-soluble vitamins, diazepam, and propofol. The choice of which system to use depends on factors such as the drug's properties, the desired route of administration, and the need for targeted delivery.

Why are cytotoxicity experiments important in drug delivery research?

Cytotoxicity tests are essential during the preclinical stage of new drug delivery system (DDS) development to determine how a drug delivery system affects the cells. The MTT assay is a common test, and others include the lactate dehydrogenase (LDH) release assay, water-soluble tetrazolium (WST), and neutral red assays. Researchers use these tests to assess the safety of new drug delivery systems before they are used in humans. Understanding how different drug delivery systems interact with cells is crucial for designing safer and more effective drug carriers.

What were the different drug delivery systems examined in this research?

The study focused on several drug delivery systems (DDSs): E, E-HS, E-P80, WLD, WLD-PCB, L, and L-Ch. The study tested cytotoxic activity in vitro on human embryonic kidney 293 (HEK-293) cells and human promyelocytic leukaemia (HL-60) cells. These systems were examined to understand how they affect cell health. The research identifies factors like the type and concentration of surfactants, and the size of lipid nanoparticles, that can influence the cytotoxic effects.

What are the key considerations for the future of drug delivery?

The future of drug delivery involves a careful balance between safety and effectiveness. The study's findings indicate that the type and concentration of surfactants, along with the size of lipid nanoparticles, can influence cytotoxic effects. While overall cytotoxicity was low, it was more pronounced with specific formulations (E-P80, WLD, L-Ch) at higher concentrations. The goal is to refine drug delivery methods by comparing the safety of different dispersions. Researchers aim to minimize adverse effects and enhance the therapeutic benefits of medical treatments.