Naprelan, being marketed in Canada by Oryx Pharmaceuticals, is a once-daily formulation of naproxen sodium, a non-steroidal anti-inflammatory drug (NSAID) which has been on the Canadian market for treating pain for more than 30 years.
The controlled-release formulation uses Elan Pharma's Intestinal Protective Drug Absorption System (IPDAS) technology, which aims to reduce the impact on the stomach and intestinal mucosa while having a controlled release of the drug.
US approval for marketing Naprelan was gained by Wyeth-Ayerst Laboratories in 1996 and is now held by Victory Pharma, but the drug has not made its way into the Canadian market.
More than 25 per cent of all anti-arthritic prescriptions are for naproxen products, of which there are more than four, making the Oryx launch of Naprelan in Canada a strategic move into the pain relief market, which for anti-arthritics sat at about $680m last year.
"Naproxen is a pretty significant molecule," Oryx president Douglas Reynolds told US-PharmaTechnologist.com.
"There's a real legacy of the product of treating mild to moderate musculoskeletal pain."
Standard formulations of naproxen and naproxen sodium, a rapidly absorbed salt formulation of naproxen, are often associated with gastrointestinal side effects because of the mucosa-irritating nature of the NSAID.
Considering the popularity of the drug, Reynolds said there was a need to provide a formulation of the drug in Canada that did not have the side effects.
"It comes down to patient convenience," he said.
"They don't have to take a pill twice a day and there's a big benefit putting in the technology - better pain control with less irritation."
Naprelan is made up of controlled release microparticle beads that have been compressed into a tablet.
Thirty per cent of the beads are an immediate release formulation released in the stomach, while 70 per cent are a sustained release formulation, which are dispersed throughout the small intestine and thereby reducing the irritative effect.
The controlled release activity is achieved through an undisclosed coating on those particles.
The formulation has been called a "fast on and lasts long" formulation because of its action of pain relief, which Reynolds said was beneficial because of the once-daily dosing and the likelihood of greater compliance with pill taking.
Naprelan is approved in Canada for the management of signs and symptoms of rheumatoid arthritis and osteoarthritis, available in strengths of 375mg and 500mg.
Nearly four million Canadians over the age of 15 suffer from osteoarthritis and rheumatoid arthritis.
Naproxen is also marketed in various formulations as Aleve, Anaprox, Naprosyn, Naprogesic and Synflex.