Researchers from the University of Osaka and Chulalongkorn University have developed a new drug delivery system that could improve the effectiveness of cannabidiol (CBD) against colorectal cancer.

The team created pH-responsive microparticles made from polyhydroxybutyrate (PHB) and cellulose acetate phthalate (CAP), both biocompatible polymers that protect CBD as it moves through the digestive tract. They demonstrated their finding in a study published by the International Journal of Biological Macromolecules.

Using response surface methodology, they optimized the formulation to achieve high encapsulation efficiency (71.8%) and stability, with the microparticles maintaining over 80% of CBD content after 90 days of storage at 4 °C. The particles averaged 211 micrometers in size and were designed to release CBD over a six-hour period in response to intestinal pH.

In lab tests, the CBD microparticles significantly inhibited the growth of Caco-2 colorectal cancer cells in a dose-dependent manner, with IC50 values of 129 μg/mL at 24 hours and 144 μg/mL at 48 hours. These results indicate promising anticancer activity while also addressing CBD’s known limitations, including poor solubility, instability in acidic environments, and low bioavailability.

The researchers concluded that PHB/CAP-based pH-responsive microparticles could provide a stable, controlled-release platform for delivering CBD as an anticancer therapy. Their work highlights the potential for more targeted and less toxic treatment options for colorectal cancer patients compared with conventional chemotherapy.