Recent domestic events have heightened the need for an effective manner in which to assure the uncontaminated delivery of contained products to a consumer, particularly medicinal products taken internally. Specifically needed is the provision of a container for such products which bears assuring indication to the consumer that the contents have not been tampered with from their point of manufacture to the point of consumer sale.
In one prior art approach toward meeting this need, use is made of so-called "telltale" indication, i.e., a readily discernible characteristic indicative of tampering, such as a visible sign that some person has previously attempted to gain access to the container contents. Broadly speaking, these efforts may be generalized as placing a tamper-indicating member, e.g., an ambient-sensitive element, in the path of access to a container to indicate tampering by discernible change, e.g., change of color of the member. A quite early example of this practice is seen in U.S. Pat. No. 1,095,313 wherein a light-sensitive label is applied to a bottle and the releasably capped bottle with such label is wrapped in a light-impermeable paper. When the wrapper is removed in ambient light, the label changes color and indication is thus provided to a subsequent purchaser that the wrapper has previously been removed. In a practice within the last decade, seen in U.S. Pat. No. 3,899,295, this technique is modernized by including the telltale substance as an interiorly disposed protected component of the wrapper. In the '295 patent, a heat-shrinkable member straddles both the cap and container vessel after capping and has a pH-sensitive integrity indicia imprinted on the interior of the member, the indicia being packaged with a basic gaseous material which maintains the indicia of a given first color. When the heat-shrinkable member is first removed from the cap and vessel, ambient pH causes the indicia to change color.
Another telltale approach is seen in situations in which containers are not releasably capped, i.e., the telltale is a component of a strippable closure member. Examples of this effort are seen in U.S. Pat. No. 3,826,221 and 3,923,198. In the '198 patent, a multilayer member serves to close the access avenue to a container and includes a layer which becomes opaque when subjected to stress. A color backing or printed legend normally visible through the stress-sensitive layer is not seen on tampering, thus providing a color change which is discernible to the user to indicate that tampering has occurred. In the '221 patent, an outer seal is adhesively secured to a container as a closure member and includes an ink which smudges if the closure member is tampered with.
In applicants' view, the latter approach is more desirable in one aspect than the former, since the latter provides indication of tampering directly at the access port rather than at a preceding wrapper removal stage. Thus, the heat-shrinkable member discussed above is a stage removed from the removal of the cap of the container and may not be present at the cap removal. However, such advantage in the latter techniques is obtained at the expense of exposing the telltale to inadvertent activating stress in the course of handling and shipping. It is applicant's further view that tamper indication should be effectively provided without need for such ambient-sensitive telltales or that more effective such ambient-sensitive telltale containers should be afforded to manufacturers.