Preserving Product with Desiccants

Companies continue to invest in desiccants to improve the shelf life and stability of new and existing drugs.

by Kassandra Kania

Development of moisture-sensitive drugs is on the rise. Products such as dissolvable films and tablets require new solutions that go beyond traditional desiccants, such as canisters and packets. And with more and more drugs being packaged and distributed globally, companies are paying attention to desiccating them for the purposes of shipping and increasing shelf life. While packets and canisters are still the preferred desiccants for most pharmaceuticals, some companies are finding new ways to keep moisture out. Others are considering oxygen absorbers as an alternative means of preserving product. Here is a look at some of the available desiccants and the drugs they are most suited for, as well as other solutions that are on the horizon.

Sachets and Packets
Industry experts have been noticing an increase in the use of packet or continuous-strip desiccants. “A good portion of the pharmaceutical market has always used canisters,” says William J. Calvo, PhD, principal scientist for Multisorb Technologies Inc. (Buffalo, NY). “There’s always been reluctance to use packets and dispensers. We’re starting to overcome that [reluctance] with more-reliable packets.” This type of desiccant also gives customers greater flexibility, says Calvo. Multisorb’s sister company, Active-Pak Automation, has developed high-speed packet dispensers that dispense both Multisorb’s and its competitors’ packets. “It keeps track of what it dispenses, so if you process 10,000 bottles, you can look at the machine and make sure it’s processed 10,000 packets. The production manager doesn’t have to worry about a couple of bottles that don’t have desiccant in them,” says Calvo. The packets also give customers greater flexibility in terms of product size. “The same product line dispenses a 3-g or a 1-g packet. You can have different production runs on the same production line.”

Brad Wolk, president of Dry Pak Industries (Los Angeles), also sees a trend toward continuous-strip desiccants. They allow customers more flexibility when making purchasing decisions, he says, because they have a variety of suppliers to choose from. In terms of safety issues, he says, packets can also bear a lot of information that helps prevent patients from mistaking the desiccant for the product. 

Canisters

The use of canisters and high-speed insertion equipment is also a popular choice for pharmaceutical companies. At one time, there was a concern about the supply of canisters, says Bob Crossno, director of sales and marketing for Süd-Chemie Performance Packaging (Belen, NM). However, Süd-Chemie has invested close to $9 million in new high-speed equipment and upgrades to increase canister supplies. The company’s Belen, NM, facility has increased canister production by 30%. One of the benefits of using canisters is high-speed insertion, says Mark A. Florez, marketing communications specialist for Süd-Chemie. “Canisters are rigid, so insertion is easy, and you do not have to stop the line.”
 
Canisters can also be custom made in virtually any size. The company is seeing an increased interest in desiccants for blister packaging in the form of a flat canister or capsule. “Companies can still have moisture problems, even if they’re using blister packaging,” says Crossno. Süd-Chemie has developed a flat canister or disk that can be inserted into its own blister. A channel down the center of the blister package creates an air passage from the desiccant to each blister. The blister containing the desiccant is differentiated from the blisters containing the drug by an orange band and a warning to consumers not to ingest the desiccant. 

Covert Desiccants

Süd-Chemie Performance Packaging offers a desiccant disk for blister packaging.

While packets and canisters can be used for a wide range of applications, some companies prefer that the desiccant be hidden from the consumer. CSP Technologies Inc. (Auburn, AL) seamlessly incorporates the desiccant into the package by embedding desiccant particulates within a network of interconnecting transmitting channels in a polymer matrix. Using a two-shot molding process, the company manufactures airtight flip-top vials that contain an inside wall made of desiccant plastic. This type of package is commonly used for diagnostic test strips and effervescent tablets. 



The company also offers desiccant films, which can be fused to the inside of a foil pouch. This type of desiccant solution is also being used by diagnostic manufacturers because it is seamless to the consumer and there is no risk involved. “The desiccant is introduced into a relatively thin-layer film—approximately 0.010 in.,” explains Billy Abrams, CSP Technologies’ vice president of business development. “It can be fused to the inside liner of a pouch. We do not need adhesive to introduce our desiccant polymer into a package,” he explains. “A lot of pharmaceuticals are very sensitive, and adhesives are notorious for releasing vapors.”



Down the road, Abrams foresees the company’s desiccant polymers, coupled with its experience in making moisture-tight seals, translating to other packaging forms, such as active dispensers that dispense a single dose at a time. “As consumers demand more and more convenience, we see a lot of interest in being able to dispense one tablet or one edible film strip at a time,” says Abrams. “The challenge for manufacturers is how to reseal the package and how to incorporate desiccant into that type of configuration. We have the technology to do so.” 



Another covert desiccant that is seeing increased use in the diagnostic industry is the tablet. “We’re getting a lot of inquiries for them and seeing a lot of people pushing toward that in the diagnostic test kit arena,” says Dry Pak Industries’ Wolk. One reason, he believes, is that the cost of tablets is starting to come down. 



Desiccants In Transit

In addition to protecting drugs from moisture on the shelf, it is important to protect them during transportation. Multisorb, Süd-Chemie, and Dry Pak Industries offer a variety of desiccants and temperature and humidity indicators for shipping containers. “There’s a growing trend toward companies wanting to know what happens to their product during shipping,” says Wolk. “FDA is mandating that companies validate temperature and storage controls of their products while in transit and storage. At the same time, these controls will tell you if you’re using enough desiccant.”



One of Dry Pak’s customers is producing bulk pharmaceuticals in the United States and shipping them to a bottling plant in Asia. The company is using an 8-oz silica gel desiccant in each drum and a temperature strip chart recorder on the pallets to monitor temperature and humidity. “The company wanted to know what happened to the goods in transit and whether they were using enough desiccant,” says Wolk. During certain times of the year, the company experienced problems with its internal packaging. The temperature recorder indicated at what point in the transit schedule the problem occurred. Based on the results, the company doubled up its desiccants and used two 8-oz bags instead of one during certain times of the year.



Looking Ahead

Experts agree that there will always be a need for desiccants, although some companies are starting to explore the option of using oxygen absorbers instead. “A lot of companies use desiccants to increase the stability of their products, but the degradation mechanism affecting their products is oxygen,” says Multisorb’s Calvo. The use of oxygen absorbers could allow some companies to market drugs that were previously put on hold because they were too unstable. The use of desiccant films is another area that is being explored further, although the cost may outweigh the benefits for some companies at this time. And as new drugs develop, desiccant manufacturers will continue to improve on existing desiccant technologies to provide moisture protection.  


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