Considerable interest has been generated by instances of tampering involving placement of dangerous foreign substances, particularly in drug or other pharmaceutical packages While there have been various improvements made to more assure the consuming public of the safety and efficacy of the packaged product, it is still difficult for a customer to determine if the package has been tampered with, particularly if the tampering was by injection of a substance by a fine hypodermic needle. In such event, the normal package material has sufficient elasticity or rheological properties to allow the resultant aperture to effectively close after removal of the needle, at least sufficient to be unobservable unless very careful inspection is made. Such would necessitate time-consuming viewing over the entire surface of the package to ascertain any small puncture mark. As a practical matter, the public cannot be taught to perform such inspection without imposition of fear and an adverse feeling against the product and its manufacturer. The overall problem has been exacerbated by poison contamination of capsules causing deaths to users and wide spread recalls of various products.
In an attempt to solve these problems, special seals have been developed for the caps sealing pharmaceutical bottles. Inflated packages, as exemplified by U.S. Pat. No. 4,449,631, have been suggested, which when ruptured would lose the inflation and a printed pattern thereon, which after deflation would be distorted and apparent to the consumer by casual inspection. The same patent discusses another attempted solution of employing color-changing pH sensitive sensors in the package which display a different color under atmospheric pressure than at a higher pressure. Such a system would be relatively expensive. U.S. Pat. No. 4,546,881 provides a heat-sealed elastomeric material vacuum-formed over the container to its elastic limit which will rupture and split upon being punctured. U.S. Pat. No. 4,436,203 includes an inner pressurized enclosure and an outer enclosure, one or both being of bellows-like configuration, the outer enclosure being closed after its internal pressure is reduced. If the outer package is pierced the package bellows sections expand or pop out giving a visual indication of tampering. While this arrangement appears operable the use of two enclosures would be costly in material and manufacturing cost and expensive in assembly over the product to be protected.
U.S. Pat. No. 2,137,745 shows a tape packaging container comprising a pair of nesting elements with a melted-in-place sealing gasket providing an hermetic seal therebetween when air is removed from the interior of the container. External pressure tends to hold the nesting elements together. A coin is used to pry the elements apart to break the gasket seal and admit air to the interior allowing overall opening of the container. In U.S. Pat. No. 4,449,632, pressured gas fills a space between two container and elastic layers tightly stretched thereover. The device deflates upon tamper-puncturing and such condition is observable. U.S. Pat. No. 4,150,744 discloses an impermeable foil envelope which is purged of air to form a vacuum around an oxygensensitive inner medication dispenser bottle. U.S. Pat. No. 4,522,666 discloses the sealing and bonding of sealed telescoping capsule parts involving a vacuum and melting of the gelatin of the capsule to form a seal. Separate ring seals have been suggested, as seen in U.S. Pat. No. 4,573,582, which fracture or distort when a closure is removed thus indicating tampering.