Halifax drug discovery company Appili Therapeutics, which specializes in developing infectious disease treatments, has bagged a United States patent for its liquid formulation of the antibiotic metronidazole.

For Appili, which was founded in 2015, the patent offers control of an alternative to metronidazole’s usual tablet form, which tastes bitter and can prove problematic for patients with difficulty swallowing.

Securing a patent is a particularly important milestone for drug companies because the 20-year monopoly they offer helps offset the extraordinary regulatory cost involved in bringing a pharmaceutical product to market.

“We believe our liquid oral reformulation solves a significant and growing issue for patients who cannot tolerate the current tablet formulation of metronidazole, especially for the elderly and children who often have difficulty taking solid oral medicines” said CEO Don Cilla in a statement.

“This patent recognizes innovative research by Appili Therapeutics to fill this significant gap in the treatment paradigm, and further strengthens (the product’s) position as a more convenient antibiotic treatment option on the market.”

Cilla, who was previously Appili’s chief development officer, became CEO in November. He is also an adjunct professor at Northeastern University, where he teaches biotechnology and economics to graduate students.

His predecessor, Armando Balboni is now the Appili’s chairman, as well as director of the Life Sciences Research Center at the United States Air Force academy.

Metronidazole, meanwhile, is widely used to treat a range of bacterial infections, such as rosacea, dental abscesses and postoperative infections. More than 10 million prescriptions for the drug are written annually in the U.S.

The patent announcement comes six months after Appili announced a deal to produce a tularemia vaccine for the U.S. Department of Defence.

The deal, worth US$14 million over two years, is an expansion of an existing agreement from February of last year. It was originally slated to see the Department of Defence spend US$10 million to fund Appili’s “nonclinical” manufacturing and regulatory activities related to the vaccine with the ultimate goal of filing a new drug application with the Food and Drug Administration.

Listed on the Toronto Stock Exchange, Appili's shares have endured a gloomy couple of years, losing about 95 per cent of their value since May, 2021. On Thursday, they rose half a cent to four cents.