Case Study by on

Glass-coated laminate shows product, protects against moisture and oxygen.

As it searches for new ways to combat diseases, Merck & Co., Ramsey, NJ, simultaneously seeks the cure for some common packaging woes. To that end, the drug manufacturer invented Cap Stick, an injection-molded thermoplastic U-shaped container. Cap Stick is filled with tablets or capsules then sealed with a clear glasscoated polyester laminate. This transparent “fourth W’dll” allows patients to see how much medication remains.

Cap Stick is reclosable. One end of the container has a thread-ed orifice which accepts a senior-friendly, child-resistant screw-in closure.

The package was developed by Leo Bunin, packaging technology manager, Merck & Co. “Losses due to non-compliance amount to billions of dollars a year in the US alone,” he says. ‘~A container whose contents are clearly visible greatly facilitates compliance.”

“People forget what medication they take and when,” Bunin points out “When a patient sees IO tablets inside the container, he can make a better judgment on what he’s already done to follow the therapy regimen. That’s why we want the product to be visible.”

MONEY-SAVER Cap Stick saves money by eliminating packaging operations. It is delivered to a tablet-filling line pre-assembled, eliminating cappers and cottoners.Cap Stick also streamlines the filling process. A stack or column of tablets is deposited in the container in a single drop. This method eliminates the need for a “slot” machine or other sophisticated filling/counting unit. Optical scanning of the stack checks the fill just before loading. Control scanning can be done after loading.

Once filled, a rectangle of ClearFoil • film laminate is positioned over the open edge of the channel body and heat-sealed to become an integral part of the package. The sealant layer of the laminate facing the product is made of the same linear, low-density polyethylene as the body. When attached-actually welded-to tl1e container, it forms a wall that cannot be peeled off or punctured, an important feature for child resistance.

The ClearFoil laminate was specified for Cap Stick to protect the shelflife of the protect inside. “When humidity comes in contact with the active ingredients of a medication, it can cause chemical deterioration,” explains Bunin. “While glass constitutes a very effective barrier against humidity and oxygen, it also makes for a heavy and bulky container.”

ClearFoil is a lightweight, flexible material produced by Rollprint Inc., Addison, IL. An exacting process deposits a thin (less than 1 micron) layer of silicon oxide on the outer surface of polyester film.


Drug manufacturers look for ways to combine senior-friendly and child-resistant features in one package. “You don’t need market research to know that existing child-resistant containers can be difficult to open for people with limited dexte1ity or vision,” says Bunin.

Cap Stick has a small, ratchet-type hidden lock, released by pressing a dot on the face of the package. Product testing has proven that this mechanism prevents small children from opening tile container. At the same time, it requires no complex manipulations or hand/eye coordination. The cap relocks automatically with an audible click when screwed into the 01ifice for reclosing.

Finally, labeling can be eliminated because the ClearFoil film laminate can be reverse or surface printed by means of tlexographic or rotogravure printing processes, and a pre-printed film will serve as a label.