Prof Joe Viljoen.
Just a few drops of oil and water may be enough to change how the world treats tuberculosis, malaria and HIV/Aids – the “big three infectious diseases”, also known as BTIDs.
This was the central message delivered by Prof Joe Viljoen during her inaugural lecture at the North-West University’s (NWU’s) Potchefstroom Campus on 13 June 2025.
Prof Viljoen, from the Faculty of Health Sciences, presented her work under the title: “Combating the BTIDs using innovative self-emulsification drug delivery systems.” Her lecture focused on how self-emulsifying drug delivery systems (SEDDSs) can improve treatment for TB, malaria and HIV/Aids.
“These diseases are mostly treated with drugs that are highly lipophilic (water insoluble),” explained Prof Viljoen. “That makes them difficult to absorb, especially for patients who are malnourished and unable to take the high-fatty meals required for proper drug uptake.”
Harnessing the body’s natural movement
SEDDSs are oil-based formulations combined with surfactants and co-surfactants. Once swallowed or applied to the skin, they mix with the body’s fluids and form fine emulsions without the need for external mixing equipment.
“With just the body’s natural movement, for example, peristalsis in the stomach, SEDDSs form into very small droplets that help drugs dissolve and be absorbed more effectively,” she said.
These delivery systems further improve bioavailability by enabling drugs to bypass the liver’s first-pass metabolism through lymphatic transport. For skin-based applications, Prof Viljoen explained the importance of choosing oils that help the drug pass through the skin where water is limited.
“We have to carefully balance the oily and water-loving components. Natural oils are key, as they help the drug penetrate the skin barrier and are better accepted by consumers due to being viewed as safer.”
Challenges in developing SEDDSs include selecting the correct ingredients, ensuring stability and controlling droplet size to regulate drug release. Tools such as pseudoternary phase diagrams help design fixed-dose combinations, especially where drugs have different solubility characteristics.
“These systems are scalable, stable and can be produced at relatively low cost,” said Prof Viljoen. “They could make a significant difference in the treatment of infectious diseases, particularly in low-resource settings.”
The lecture concluded with a call for interdisciplinary efforts to advance the development of SEDDS-based therapies.