Types of Child-Resistant, Senior-Friendly Drug Closure Systems

Sanner of America decided to adopt a push-and-turn mechanism for its new closure. To assist seniors in opening the closure mechanism, it designed an opening tool that inserts into the top of the screw cap. The tool requires less effort than the traditional push-and-turn process, yet independent testing has shown that children are not able to use the tool themselves. This is due to the tool having to be put into grooves on the closure top just right, while holding and turning it simultaneously.

Captive Plastics decided to design a one-piece push-and-turn closure as opposed to the two-piece design. With the two-piece design, it is difficult to determine when the closure is open. With Captive Plastics’ one-piece design, once you push and turn it, it pops up, providing visual and audible evidence. Not only is this design lightweight, but it also costs less because a high number of cavities can be used during the molding process.

The most popular type of one-piece closure is the squeeze-and-turn design. This design minimizes the force needed to squeeze the cap and open it. However, the challenge facing one-piece squeeze-and-turn closure designers is to find a child-resistant design that seals efficiently.

Another challenge facing closure designers is ensuring that small closures, those under 24mm, pass the CPSC’s protocol. Seniors have difficulty grabbing small objects. But, closure designers don’t feel as though size modification is the solution. The package must be aesthetically pleasing and marketable.

An alternative to the push-and-turn and squeeze-and-turn designs, closure designers have also designed the line-up-the-arrows mechanism. This design requires the consumer to line up corresponding arrows on caps and bottles and lift the lid. The problem with this design is that consumers aren’t patient enough to follow complicated instructions. In a dark room, colored arrows cannot be seen. Colored arrows would also make it easier for children to open the closure.

Many closure designers are incorporating other features to help companies save steps in the packaging process and reduce the number of vendors. Sanner’s closure has a hinged breakaway tab on the top of the lid that pops out when the child-resistant mechanism is activated through either pushing and turning or pulling down on the cap. It provides tamper evidence to the consumer, also. If the tab is absent, it is indicative that the bottle has been opened. It also has a tear band at the base of the closure. The closure can be supplied with a built-in desiccant cartridge that can hold either 2g of silica gel or 3g of a molecular-sieve adsorbing material.

To enable consumers to quickly identify the bottle’s contents, Kerr’s child-resistant closure has a clear cap. Owens-Brockway designed their two-piece push-and-turn closure, named MedTime. It has an indexing mechanism that advances each time it is closed. This helps the consumer keep track of each dose. Rexam Closures combined a flexible blister package with a rigid plastic device. It is a child-resistant "compact-like" molded mechanism that acts as a display carton and a shipping device.

Stull Technologies designed a new child-resistant closure called the StullSure. It, too, passed the protocol testing with a near-perfect success rate. The closure is a one-piece flip-top designed for personal care and cosmetic products containing 10% or more low-viscosity hydrocarbons by weight. The StullSure looks and functions like a standard flip-top closure to maintain an aesthetically pleasing look. The StullSure uses a locking device that snaps on to a bottle, hindering removal.

Alcan Packaging designed an injection-molded, single-piece closure. It features an outer sleeve rotating around an inner sleeve. The closure can only be opened when two buttons are pressed while the cap is turned. This button-lock design is aesthetically pleasing and offers a cost-effective alternative to existing child-resistant closures.

More closure systems will be discussed in Part 2.

Food and Drug Packaging
Information on drug closure systems.