Researchers at Case Western Reserve University have developed a targeted drug delivery system that is triggered by the acidic environment around a tumor.

The system delivers chemotherapy to the tumor for 40 days and doesn’t affect healthy tissues, according to a preclinical study published in Experimental Biology and Medicine. 

Traditional cancer therapy sometimes requires patients to receive a drug intravenously, which sends drugs throughout the patient’s system and can yield toxic side effects. Often, this route of administration reduces the number of cancer cells that are killed by the therapy. Instead, researchers are trying to develop alternative drug delivery systems that increase drug efficacy and minimize damage to healthy tissue.

Some studies have shown that pH-sensitive delivery technologies can overcome the toxic side effects of doxorubicin, a chemotherapeutic. But this team pointed out that those systems often cannot sustain the drug-release that is necessary for killing tumor cells.

Horst von Recum and his team developed a targeted drug delivery system for doxorubicin that is triggered by the acidic environment surrounding a tumor and releases the drug at the tumor for 40 days. The team reported that the drug did not release in the neutral regions around healthy tissues.

The modified doxorubicin was the same as the unmodified drug, according to the team. The system can release doxorubicin for 10 times as long as other pH-sensitive systems, which could eventually mean fewer doses for a patient.

“We feel that this is a new lease on the life of doxorubicin, a great anti-cancer drug, since the total contained dose is far lower than that used systemically and well below the toxicity threshold of the heart,” von Recum said in prepared remarks.

“von Recum and colleagues have provided a pH-sensitive DOX delivery system that allows delivery at a slow and steady rate that is specific to tumor tissue,” the journal’s editor-in-chief, Steven Goodman, added. “The next step would be animal testing.”