Medical Device Link.

Originally Published July 2000

PHARMACEUTICALS

Desiccants: Automating Insertion

To find the right desiccant for your application, carefully examine your automation requirements and your product volumes.

Desiccants are vital for maintaining the integrity and effectiveness of a wide range of pharmaceutical, nutritional, and in vitro diagnostic (IVD) products. To meet demand for specialized applications, desiccant manufacturers have devised a variety of formats—canisters, packets, tablets, capsules, filled stoppers, and more—to hold the silica gel, montmorillonite clay, or molecular sieve desiccant. The workhorses accounting for the greatest share of this market, however, are desiccant canisters and continuous-strip packets for high-speed automated dispensing.

Süd-Chemie markets the effervescent-PAK as an alternative to foil for nutritional and pharmaceutical effervescents.

Your choice in desiccants depends upon a variety of requirements, including production, volume, environmental, and regulatory ones. Before determining a particular style—or before switching from one style to another—check out the latest developments in automation, technologies, and regulations.

CANISTERS VS. PACKETS

In the beginning, desiccants were available only in packets for the pharmaceutical industry. As volumes increased, manufacturers began to look for ways of automating desiccant insertion. The desiccant canister was developed to meet that need for high-speed, automated insertion.

Because canisters were so much more expensive to manufacture than packets, though, desiccant suppliers and equipment manufacturers continued to search for a way to automate the dispensing of packets. Eventually, they hit upon the idea of manufacturing continuous spools or fanfolded strips of packets to be dispensed from a piece of equipment descended from an automated label cutter/dispenser.

The early-model automated packet dispensers offered in the late 1980s, however, left a lot to be desired in terms of dispensing packets efficiently and reliably. One persistent problem was the slicing of packets in the middle, which contaminated the entire packaging line with spewed desiccant. Automated packet insertion got a bad reputation.

Engineers have now solved the reliability problem. In 1999, Multisorb Technologies Inc. (Buffalo, NY) spun off a sister company, Active-Pak Automation (APA; Orchard Park, NY), to offer the APA series of automatic packet dispenser systems. AZCO Corp. (Elmwood Park, NJ), a leading manufacturer of high-precision feeding and cutting machines for all flexible materials, offers the SP (Sure Pack) family of packet dispensers. Both have incorporated sophisticated electronics to ensure alignment or registration of the packet strip at startup, replaced the pinch or nip rollers that were prone to slippage with more-reliable flat belts, and employed a photoregistration device to detect the clear area or punched holes between packets as a target for cutting. (See the sidebar below, "Did the Desiccant Drop?")

APA's dispenser accurately cuts and places packets into 30-cm³ bottles at speeds up to 300 bpm.

While manufacturers were working out the kinks with packet dispensers, however, canister dispensers became the gold standard for automated desiccant insertion. They are entrenched in high-speed, high-volume pharmaceutical and nutritional-product lines.

Not only reliability but also speed makes canister dispensers tough to beat. Omega Design Corp. (Exton, PA) claims speeds up to 500 canisters per minute for its in-line canister desiccant feeder. The highest speeds quoted for packet dispensers are around 300 packets a minute, for AZCO's SP-110 and APA's APA-2000. APA recently delivered a system to a drug maker that places desiccants into bottles at a speed of 300 packets per minute.

Nevertheless, the powerful lures of lower cost and greater availability have prompted manufacturers to take another look at packets. Often as little as half the cost of canisters, packets dispensed at slightly slower speeds will still net the manufacturer a cost savings.

Furthermore, canisters are available in a limited range of standard sizes from only three main suppliers in the United States. Because these suppliers were overwhelmed by demand last year, "they were quoting lead times up to 16 to 20 weeks to some customers," remembers Brad Wolk, business development manager for Desiccare Inc. (Santa Fe Springs, CA). "This shortage led a lot of customers to believe that the switch to packets is imperative if they want to survive," he adds.

To remedy this shortage, Süd-Chemie Performance Packaging (New Belen, NM) recently upgraded its canister production, adding three high-capacity canister-filling lines. The first produces 2- to 3-g canisters at speeds up to 500 canisters per minute; the second produces 1-g printed canisters at speeds up to 1000 canisters per minute; and the third, a sister to the second, features high-speed labelers and will run at speeds up to 1000 canisters per minute. The firm says such high-capacity production will make canisters more cost-effective than before.

MAKING THE SWITCH

The problem with switching from canisters to packets for mature product lines, of course, has been the regulatory hurdles that must be overcome when any packaging component is changed. These hurdles shrank in November 1999 when FDA's Center for Drug Evaluation and Research (CDER) published the guidance document "Changes to an Approved NDA or ANDA." A manufacturer can now implement a change of desiccant as soon as FDA has received its submission of a "Supplement—Changes Being Effected in 30 Days," or CBE-30.

A draft guidance document, "Stability Testing of Drug Substances and Drug Products," issued by both CDER and FDA's Center for Biologics Evaluation and Research (CBER), further clarifies requirements for desiccant changes. This guidance document proposes not only to reduce the requirements for stability trials supporting a change from one desiccant format to another but also to change the notification process. "Instead of being required to do stability trials up front, submit an amendment to an NDA, and wait for approval, the firm will be able to make certain desiccant changes and do much-reduced stability work after the fact and file it as part of its annual submission to FDA," explains John Brennan, APA's group leader.

The shortage of desiccant canisters was the impetus for the changes in the guidance documents, Brennan speculates. "FDA is not necessarily concerned with the cost of a packaging component, but when an industry shortage of a component might hinder production of, for example, a life-saving drug, then it becomes an issue that FDA is willing to talk about," he explains wryly.

Multisorb has gone a step further to expedite changes in desiccant format for their customers who desire to do so. Working closely with FDA, they have created a Drug Master File (DMF 7092, section 10, volume 4) that includes equivalency data for packets and canisters.

SPECIALIZED APPLICATIONS

While the vast bulk of desiccants are packaged in canisters or packets, other formats have been developed for niche markets. Polyethylene caps incorporating desiccant stoppers that snap onto polypropylene tubes have been available for years, but screw-top caps with desiccant stopper inserts are a new twist. Spring-loaded cap and tube combinations, another new development, have been developed specifically for the effervescent product market.

Süd-Chemie has designed an insert containing a desiccant that snaps into a threaded cap. This design eliminates the possibility that the end-user of a pharmaceutical or nutritional product will discard the desiccant, thereby compromising product effectiveness, or accidentally ingest the desiccant. Furthermore, if the cap maker supplies the cap and the washer together, then the packager has no need for an insertion machine for desiccant canisters or packets, explains Robert Crossno, Süd-Chemie's regional sales manager.

A few factors limit applications for this technology. The inserts are available in a limited range of standard cap sizes, unless a customer demands a large enough quantity to justify custom manufacturing. Once the desiccant inserts have been placed in the caps, the caps must be packaged, shipped, and stored in conditions appropriate for desiccants, which may be a logistics challenge for cap manufacturers.

"Where these washers I think are going to really fall into place is for people who are packaging powdered vitamins and nutritional products," predicts Crossno. "Currently, manufacturers have no choice but to put the desiccant, either packet or canister, in that powder, and it creates a mess." Pharmaceuticals are a big market as well, he says.

Another new packaging option for the nutritional and pharmaceutical market is Süd-Chemie's effervescent-PAK, which consists of a tube and a pressure-fit cap with the desiccant in a stopper, plus a polyethylene spring to hold effervescent tablets in place. This package is primarily an alternative to foil. With foil, Crossno says, ensuring consistent seals can be a challenge, and the effervescent tablets are easily broken. Effervescent-PAK's rigid tube not only minimizes breakage, but it also can take five-color print work.

Amerilab Technologies Inc. (New Hope, MN) is a contract manufacturer producing about 30 effervescent products, some for the United States and some for world markets. One barrier to entry into effervescence, says Fred Wehling, president and CEO of Amerilab, is the scarcity of equipment. Consequently, Wehling designed and built his own semiautomated equipment. Currently, the tablets are sorted and assembled into lanes automatically, then slipped into the tubes manually. The tubes are then capped automatically. When output reaches 100,000 tubes a month, Wehling says, the firm will be able to justify the cost of a completely automated line. Süd-Chemie points out that there is one U.S. provider that offers such equipment, European Packaging Machinery (Tennent, NJ).

Last year, Süd-Chemie introduced 2AP, a proprietary technology for incorporating desiccant into injection-molded plastic components. The technology has potential for the medical device market, especially for IVDs. "We are looking at injection molding the entire housing of, say, a pregnancy kit, with the desiccant in the plastic," Crossno says.

COST AND SERVICE

Some manufacturers require high-tech desiccant solutions for their specialized applications, and they are paying more for something that works in their product. But most users see desiccants as a commodity item, and the biggest advance they seek is lower cost.

Ralph Hanna, director of materials of LXN Corp. (San Diego), says his company cut material costs by about 60% a year and a half ago by switching suppliers. LXN uses Süd-Chemie's tubes and stopper caps loaded with 2 g of silica gel for packaging the glucose monitoring strips in its Duet and InCharge Diabetes Control Systems. Not only cost but also service drove LXN to switch suppliers. "The package we were using previously wasn't available direct from the manufacturer," Hanna says, "and we had to buy through distribution, with associated longer lead times and lack of connection with the supplier."

Wolk says Desiccare's strategy is to capitalize on the cost-lowering trend by offering high-quality pouch desiccants. "Otherwise, you can go in a million different directions with development, and 10 years from now you may find you've wasted your resources on equipment for a short-lived fad."