CASE HISTORY: Packaging Saves Time, Space

Suppliers worked with a pharmaceutical maker to produce unit-dose packaging that saves nurses time and frees storage space.

When the engineers at Stone Pharmaceuti-cals (Philadelphia) decided to design a new unit-dose package for the firm's mouthwash and other liquid pharmaceutical products, they wanted to create one that would be easier to use and would take up less storage space than conventionally packaged liquids. They took into account the effort nurses currently expend when dispensing such pharmaceuticals—either by measuring equal doses from one container or counting out and keeping track of separate unit-dose containers—and the emphasis hospital administrators place on reducing storage costs. The engineers envisioned a stackable package that would reduce storage costs without changing the dosage amounts of the units.


To produce such a package, Stone engineers needed to find materials for the cups and the lid stock as well as machinery to form, fill, and seal the cups. "We needed a film with a low moisture vapor transmission rate so the product could be stored for 12 months," explains Robert Malerman, general manager at Stone. The material also had to be capable of holding liquids with alcohol content or with high or low pH.

Finding the right lid stock was more challenging. "We had three criteria for the lid stock: it had to be rigid enough to hold the 12 unit doses, it had to have a tight seal, and it had to peel cleanly and easily without tearing," says Malerman.

Stone engineers also had to obtain a new machine that could handle all the forming, filling, and sealing. "A precise registration of ±1 mm was essential," explains Malerman, "because the blisters were to be formed in a continuous web, filled, sealed with lid stock, and then the sealed containers were to be cut out of the web."


After more than two years of collaborating with three suppliers, Stone introduced its new liquid unit-dose packaging: a set of 12 1-oz thermoformed cups sealed to a perforated sheet of rigid lid stock that is designed to stack compactly by fitting the bottom of one 12-unit set into the bottom of another. According to Malerman, the nestable packaging allows hospitals to store 24 doses "in half the space of conventional right-side-up trays of doses stacked one on top of the other."

Each 1-oz unit holds up to 3/4 oz of fluid and can be detached from the sheet for dispensing. Pull tabs at the corners ease opening.

The Stone engineers worked with Gordonsville, VA—based Klöckner Pentaplast of America from the beginning of the project. For the thermoformed cups, they chose the firm's Pentapharm 757/ 08, a clear vinyl that has a thickness of 25 mil. After trying several materials, Reynolds Metals (Richmond, VA) developed a lid stock and a heat-sealable coating compatible with both the blister film and the liquid. Because of the lid stock's rigidity, no secondary packaging is required; the lid stock acts like a tray.

Reynolds also created a seal that retains integrity even when the package is turned upside down. The lid stock and the seal had to be designed so that nothing from the product would migrate through the heat-sealed coating and cause the foil to delaminate.

After locating Klöckner Medipak's (Clearwater, FL) Compacker-3 form, fill, and seal machine at a trade show, Stone engineers first used it for manufacturing other types of containers. "Although we also use it to produce conventional liquid or paste unit-dose packages, we bought the CP-3 with this nestable package in mind," Malerman explains.

Not only does the CP-3 thermoformer perform the entire packaging process, but its deep-draw and quick changeover capabilities will allow Stone Pharmaceuticals to expand its contract packaging services.


Photo courtesy of Reynolds Metals Co.

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