Although they have been around since the 1950s, pressurised metered-dose inhalers (pMDI) most have a significant design flaw because there is nothing to indicate when they are empty, claims Valois. This may have serious risks for the patient, for example in the event of a sudden attack of asthma, for example.
According to a study conducted at the University of Michigan in 1995, this shortcoming "likely causes patients to extend the use of their meter-dose inhalers beyond the specified maximum number of actuations [and] this practice may well contribute to the documented rise in asthma morbidity and mortality."
In addition, the study found that as many as 54 per cent of patients were not aware of the maximum number of actuations in their canister and only 8 per cent of patients actually tracked the number of actuations used. This has led to calls for dose counters to be included as standard on pMDIs.
For example, in March 2003, the US Food and Drug Administration published guidelines requiring the pharmaceutical industry to incorporate dose counters in all pMDIs used in new products intended for the US market. Valois said it had anticipated this and was already working on a counter - called Landmark - which is now available less than 18 months later.
The company claims the Landmark counter can be incorporated in any type of pMDI, and can be adapted to count up to 200 doses. It indicates the quantity remaining in the device using a digit and colour display system.
Landmark is also arriving on what is a particularly buoyant pMDI market, representing a total of 500 million units a year, according to Valois.
At present, dose counters are mandatory only in the US, but the company believes the concept will be adopted in other countries, including Europe, in the near future. And European companies are already signing up for this type of technology: last December, Italy's Chiesi licensed rights to a dose counter developed by Canada-headquartered Trudell Medical International, both for the US and international markets.
Several drug products incorporating Landmark are already in product development phases. The first of these will be on the market within three years, said Valois.