Multisorb's latest innovation to leave inhalable meds high and dry

The company's latest offering for the pharma industry involves incorporating desiccant within a thermoplastic used to make the inhaler structure. "Rather than having a built-in desiccant in an available space, we can take polysorb, which is 40 per cent molecular sieve desiccant in a thermoplastic and make non-functional components,"​ explained global manager of the company's pharmaceutical business, Adrian Possumato, when US-PharmaTechnologist caught up with him at the recent Interphex pharmaceutical trade show in New York. Making the desiccant part of the physical structure of dry powder inhalers, actuators or aerosol pressurised metered dose inhalers offers an alternative moisture management solution to manufacturers that can solve some of the issues common with more traditional desiccant products. For example, Possumato noted that there can often be a problem for consumers when desiccant canisters are used in inhaler products, because when they shake the device they hear movement of particles and assume there is still medication in the inhaler. Even though there may be a counter on the inhaler showing that the device is empty, consumers often still believe there is drug product left which can leave them in danger of trying to evacuate the inhaler and getting no medicine. Although Multisorb has developed a compressed desiccant tablet in coated solid form which offers a solution to this problem (and is currently being used with GlaxoSmithKline's tablet-form migraine product Trexima (sumatriptan and naproxen)), incorporating desiccant within the plastic inhaler structure still has distinct advantages as an alternative solution. One of the key arguments in favour of the product is the role it can play in the case of inhalers based on the new propellant hydrofluoroalkane (HFA), already in widespread use in European inhaler products and due to become increasingly common on the US market following the US Food and Drug Administration (FDA) drive to rid the market of all CFC-based propellants by 2008. The difficulty with HFA, Possumato explained, is that it absorbs moisture very readily which is a problem when it is used in aerosol inhaler products. When the inhaler is used, a dose of drug is discharged from the dosage chamber and released, and the chamber then gets filled with the next dose. "The dosage chamber is not very well protected,"​ said Possumato. "It pulls in moisture, it hydrates and crystallises the drug, which means it can't now pass through the valve system. So it affects dosage control as well as the physical stability of the drug product." ​ The problem for manufacturers producing HFA inhalers is that GlaxoSmithKline (GSK) has pipped them to the post by getting in early and patenting a straightforward moisture management system that the company uses with its HFA-based Ventolin (albuterol sulphate) and Flovent (fluticasone propionate) products. GSK uses a simple desiccant sachet in an aluminium pouch flow-wrapping machine for all of the company's US-distributed HFA aerosol inhalers and has patented this, leaving other manufacturers having to find alternatives. Desiccant-enriched thermoplastic could offer a solution for these manufacturers, and according to Possumato can be used in any moulded device in any inhalation system. Although it could be a couple of years before the solution is actually launched in a pharmaceutical product, the concept has already been proved though use in other non-pharmaceutical applications. The one downside of the solution is the cost. Being more high-tech than a simple drop-in sachet or canister, the thermoplastic products will come with a price tag that reflects the additional complexity of the solution. As the product would involve custom moulds and design work as well as the plastic itself (which would make up 60 per cent of the structure), the cost would probably be a significant step up from the standard line of desiccant products. "It's not cheap for people to get that level of protection,"​ said Multisorb's marketing leader, Rich Burke. "A sachet is very inexpensive, but if you want some sort of long-term protection for your inhaler, you need to work at it." ​ Another point where standard products such as sachets fall down, according to Possumato, is that they can easily be discarded by pharmacists or consumers leaving products with no ongoing protection. The thermoplastic product would provide a second line of protection should the primary protection device such as a sachet or canister be removed. The novel thermoplastic desiccant solution that Multisorb is hoping to bring to the pharma industry could find particular application in the growing field of respiratory drug delivery, which offers the potential of delivering not only small molecules but larger molecules such as insulin or beta interferon. "Inhalation methods can revolutionise the way vaccinations are carried out,"​ said Burke. "It takes away the risk of needle-stick injuries, blood-borne diseases from using the same needle multiple times, it lowers the cost, there's no refrigeration required - and we can stabilise it with our products. We've opened up a whole new market." ​ With Multisorb's pharma business growing at rate of around 38 per cent a year, the company is already enjoying its fairly comfortable spot in the market. However, the confidence the firm has in the blossoming field of respiratory drug delivery and the role that its products can play in enabling these products to successfully come to market suggest that it expects the company's position in the industry to grow ever stronger over the coming years.