Next-generation drug delivery systems could transform oral cancer treatment

Oral cancer kills. Oral squamous cell carcinoma—OSCC—ranks among the most common malignancies of the mouth and throat, and it carries a heavy toll in suffering and death across the globe. Treating it has always meant a hard choice: flood the body with chemotherapy or radiation, accepting the collateral damage, or accept limited options. A new review published in the European Journal of Pharmaceutics and Biopharmaceutics in August 2026 proposes a different path: deliver the drug directly to the tumor site, where it can work without poisoning the rest of the patient.

The idea sounds elegant. Put medicine exactly where it needs to go, keep it there long enough to do its job, and spare the body the toxicity of systemic treatment. But the mouth is not a passive container. It is a working organ—constantly producing saliva, moving, chewing, speaking. Saliva dilutes and washes away drugs. Enzymes break them down. The tongue and teeth dislodge anything that tries to stick around. These are not minor inconveniences. They are what the researchers, led by Professor Nurhasni Hasan of Hasanuddin University in Indonesia, call "hard constraints"—fundamental barriers that any drug delivery system must overcome to work at all.

Hasan and her collaborators from Japan and China examined four main approaches to local delivery: mucoadhesive films and patches that adhere to the mouth's lining; oral sprays that coat the lesion; in situ gels that form on contact; and injectable hydrogels that can be placed directly into or around the tumor. Each has strengths and weaknesses that depend on the shape and location of the cancer. A flat, accessible lesion might work well with a film that sticks to the tissue and releases drug over time. An irregular or deeply infiltrative tumor might need a gel or injectable hydrogel that can conform to the complex surface and penetrate deeper layers. Sprays are easy to apply but wash away quickly because of saliva.

There is another complication: the cancer treatment itself changes the mouth. Radiotherapy and chemotherapy cause xerostomia—dry mouth—and damage the mucous membranes. This alters the pH, the enzyme activity, the flow of saliva, and the ability of any delivery system to stick or release its payload predictably. A formulation that works in a laboratory petri dish may fail in a patient whose mouth has been ravaged by cancer treatment. The researchers emphasize that future studies must test these systems under realistic conditions: with actual salivary flow, with mechanical stress from chewing and tongue movement, with the changing chemistry of a treated oral cavity.

Hasan stresses that the real challenge is not just inventing a better formulation—it is matching the right formulation to the right drug, the right tumor, and the right patient. "A sophisticated technology has limited clinical value if it is difficult to manufacture, administer or tolerate," she said. This is where the review's framework becomes practical. Mucoadhesive films and patches already have regulatory pathways and manufacturing experience from other buccal delivery drugs, giving them a clearer near-term path to the clinic. Injectable hydrogels, while promising for complex lesions, still face hurdles in manufacturing, gelation control, degradation, clinical application, and long-term safety.

None of these technologies are yet standard treatments for oral cancer. What the review offers is a map for getting there—a way to think about which system might work for which situation, and what questions researchers and clinicians need to answer before moving forward. The goal, Hasan concludes, is not simply to deliver a drug to the mouth. It is to ensure that the right amount of drug reaches the right place and stays there for the right amount of time. That precision, that predictability, is what could transform oral cancer treatment from a choice between bad options into something genuinely better.