Environmentally controlled medication container

This invention relates to a container for carrying temperature-sensitive materials, having a case and inner chamber separated by a cavity containing thermal insulation, characterized in that the thermal insulating means includes a heat sink whereby the contents of the inner cavity is protected from a temperature increase for a period sufficient to avoid deterioration under normal conditions of use.

This invention is directed to means for protecting pharmaceutical 
preparations or other chemicals from degradation by ambient conditions of 
temperature and environment. 
BACKGROUND OF THE INVENTION 
Many materials, and notably a large range of important pharmaceutical 
preparations, are subject to accelerated degradation by temperature and 
other environmental conditions. In particular, a number of commonly 
prescribed medications are temperature and light unstable. The best known 
is glyceryltrinitrate. Others include benzodiazepines, prochlorperazine, 
penicillin, pseudoephedrine, promethazine, prednisolone and captopril. 
The manufacturers of glyceryltrinitrate recommend that the tablets be 
stored at temperatures of less than 25.degree. C. and protected from 
light. The standard brown glass bottle falls far short of these criteria; 
for example these types of containers reach an internal temperature of 
25.degree. C. within 20 minutes of removal from a refrigerator, and the 
temperature of tablets carried in a shirt or trouser pocket rapidly 
reaches 35.degree. C. 
There have been two previous attempts to provide an insulated container for 
heat-sensitive materials. Southwick (U.S. Pat. No. 3,472,568; 1969) 
describes a fibre container having an inner insulating layer with a 
removable inner receptacle, the insulating layer being surrounded by a 
hard exterior shell with detachable top. The novel feature of this 
invention was a humidity control device. This invention was not directed 
specifically at protection of pharmaceuticals. Lowe (U.S. Pat. No. 
4,054,208; 1977) describes a container for medicinal tablets, capsules or 
pills, to be carried on the person, consisting of two concentric 
cylindrical tubes, the inner tube being of translucent amber-coloured 
plastic or glass, separated from an outer transparent tube by an air 
space. This invention was intended to protect pharmaceutical products from 
body heat, light, and moisture, as well as from mechanical damage. No 
insulation or heat-protective device other than the airspace was 
incorporated into the invention. 
It is an object of this invention to overcome the defects of the prior art 
by providing a container with superior protective properties, particularly 
against the deleterious effects of heat. 
GENERAL DESCRIPTION OF THE INVENTION 
In a general aspect the invention provides a container having an outer 
case, and an inner chamber, which may for example be cylindrical and 
suitable for holding a small number of tablets. The cavity between the 
chamber and the case contains thermal insulating material, including a 
heat sink, so that the contents of the chamber are protected from 
deleterious rise in temperature following a rise in temperature of the 
case, as will occur when the container is removed from a refrigerator and 
carried on the user's person. 
In a more particular aspect the invention provides a container having an 
outer case and an inner chamber, and thermal insulating means 
therebetween, characterized in that the thermal insulating means includes 
a heat sink whereby rise in temperature of the contents of the inner 
chamber following exposure of the outer casing to an increased temperature 
is delayed for a period sufficient to avoid deterioration of the contents 
of the chamber, under normal conditions of use. 
The outer case is preferably made of opaque, rigid material. 
The heat sink, which may comprise degraded collagen matrix containing 
thermal and chemical stabilizers, is preferably surrounded by a reflecting 
and conductive shield. It may also be surrounded by heat insulating foam, 
for example expanded polystyrene. 
SUMMARY AND DETAILED DESCRIPTION 
The present invention incorporates the use of an opaque, inert, rigid 
construction material to protect the contents of the container from 
mechanical damage and from degradation by light. Insulating layers of foam 
and of aluminium foil, and the use of a heat sink chamber to surround the 
tablet chamber also give excellent protection of the contents from heat.

The container comprises an external case 1 of synthetic resinous material 
having a ridged, hinged lid 2 which carries a stopper, 3 which registers 
with medication tube, 4 to seal the said tube in an airtight manner. The 
container is internally insulated by a multi-layer reflecting shield 
comprising aluminium foil layers 2 and 6, an expanded polystyrene layer 7, 
surrounding heat sink 8, containing degraded collagen matrix and agar 
having metabisulphite as chemical stabilizer. Heat sink 8 surrounds tablet 
tube 4, which is made from a synthetic resin which does not absorb the 
vapour phase of the contained medication e.g. polyethylene or 
polypropylene in the case of glyceryltrinitrate. 
This container will maintain an internal temperature of less than 
25.degree. C. for over 4 hours after removal from the refrigerator and 
returns to base temperature within 30 to 60 minutes when placed in a 
normal domestic refrigerator or freezer. 
The present container is not intended to replace the manufacturer's 
container. It is designed to ensure that prescribed medications remain 
stable whilst they are carried about the person. The following embodiments 
are within the scope of this invention.