Disposable tube for rectal injection of drugs

A disposable tube includes two compartments separated by a breakable partition. One of the compartments initially contains one element of a medicament, the other compartment initially contains a second element of the medicament. The first compartment, includes a bellows, maintained compressed in its initial condition. The partition is breakable whereby the first and second elements are mixed together. The bellows is expandable from its initial condition whereby the second element is drawn into the first compartment for mixing the first and second elements together. A hollow tip permits evacuating the interior of the first and second compartments for administration of the mixture.

This invention relates to a disposable tube for rectal injection of 
medicaments. Till now such tubes have mainly been used for injecting an 
apportioned quantity of a laxative. Contrary to tubes intended for 
cosmetics or paints and glue and having a short neck, which is closed by a 
screw-cap, then syringe-tubes have a comparatively long neck making it 
possible to conduct the medicament high enough up to act on the colon. 
Except for laxatives, medicaments to be administered by the patient 
himself, e.g. pain-stilling remedies or antibiotics, till now have been 
given in the form of pills, while e.g. stronger and quick action 
analgesics are injected by means of hypodermic needles and are 
administered by experts. Pills which are swallowed must pass the stomach 
and this has at best a delaying effect as an absorption at the earliest 
takes place in the intestinal canal, and at worst they have such an 
irritating effect on the stomach that they may lead to a gastric catarrh 
or even to vomiting. 
Therefore there exists a requirement for medicaments which can be given 
rectally. Such do exist. E.g. there are analgesics available which are 
meant for rectal injection in a liquid state, but these are not stable in 
their ready condition, and consequently they are supplied in the form of a 
powder and a dissolvent which will be mixed immediately before they are 
injected. Therefore, syringe-tubes as above are not applicable, as it is 
unpredictable how long a time will elapse from the charging and 
weld-closing of the tube till it is emptied by a user. 
There exist tubes divided into two chambers by a partition, said tubes 
being intended for containing a drug component each, e.g. a powder and a 
solvent, which must not be mixed till immediately before use. Precedents 
of such tubes are for instance described in U.S. Pat. No. 2,176,923. The 
tube described therein is divided into two chambers by a dividing wall 
having weakening lines or thin areas, so that said wall is broken by 
pressure thus allowing a liquid to flow from one chamber into the other. 
Another example of such tubes are described in U.S. Pat. No. 3,347,410 
which deals with a double-walled tube. A barrage membrane between the 
walls can be perforated by a tack attached to a bellows-shaped tube neck, 
so that said tack penetrates the membrane when the tube neck is 
compressed. 
Such tubes are not very suitable for rectal injection of drugs to be mixed 
in the tube when the injection must be carried out by the user 
himself/herself. 
In order to obtain a swift and safe dissolution of the powdered drug 
component, the greater part of the solvent must be conducted to the 
chamber containing the powder, which implies that the two chambers must 
have almost the same volume. This increased volume alone makes the tube 
unwieldy for the user, but add to this that a partition placed in the 
middle of the tube-casing makes it difficult to have a sufficient emptying 
of the tube when it is squeezed together. An insufficient emptying not 
only mean loss of some medicament, but also a doubtful dosing of the 
latter. 
It is the aim of this invention to manufacture a disposable tube for rectal 
injection of the above sort, being divided into two chambers by a 
partition and having means to break the partition wall and not taking up 
more space than would a tube containing the ready-mixed drug, without 
making it more complicated to use it than anybody being able to manage. 
According to the invention this is obtained by the fact that the section of 
the tube-casing reaching from the partition wall to the tip of the tube is 
shaped as an extractable bellows. 
In its normal state, i.e. when the tube is delivered charged with drug and 
dissolvent, and when injection is carried out, the bellows is compressed. 
When the medicament is going to be ready-mixed the partition wall is 
perforated in a well-known way, either bursting it by a strong pressure on 
the tube or perforating it with a pointed rod which is put down through 
the tip of the tube, after which the bellows is drawn or pressed out thus 
providing so much space that all of or nearly all of the dissolvent can be 
contained. When the drug is dissolved the bellows-shaped part of the 
casing can be compressed again and the injection be carried out just as 
easily and conveniently as with a normal one-chamber tube made for rectal 
injection. 
In order to make it possible to fill the tube in the usual way through its 
not yet closed and sealed end, according to an embodiment of the invention 
the dividing wall may be constituted of the bottom of a tubular insert, 
which when the powdered drug has been charged is inserted into the tube to 
bear against the bellows-shaped part of said tube. When the dissolvent has 
been charged, the closing of the tube can be done in the usual way, viz. 
by simultaneously welding the insert and the tube-case along the 
compressed bottom edge.

The tube shown in the drawing consists of a thin-walled case 1, the top of 
which is shaped as an extractable bellows 2. In FIG. 2 the bellows 2 is 
shown in its extracted state. The tube has a hollow tip 3 of which the 
exterior is slightly conical, and until it is used said tip is closed by 
e.g. a pressed-on cap, or as shown in the drawing by a rod-shaped plug 4 
which has an extension 13 ending in a point 14. By a partition 12 the case 
1 is divided into two compartments 5 and 6; the compartment 5 which is 
constituted of the extractable part of the case is designed to contain the 
powdered drug, whereas the compartment 6 is intended for containing a 
solvent. As it appears from FIG. 2 the partition 12 is made up of the 
bottom section of a tubular, thin-walled insert 7 which, when the powdered 
drug has been charged, is inserted into the smooth part of the case 1, 
and, when filled with the solvent, it is welded together with the case 
along its bottom edge as shown in FIG. 1. 
As it is known from the previously mentioned U.S. Pat. No. 2,176,923, the 
bottom 12 of the casing 7 may have weakenings making it burst at a strong 
pressure. A simpler, and a fully as reliable design is obtained by 
providing the tube with a rod-shaped plug 4 as it is shown in the drawing. 
FIG. 1 shows the plug partially drawn out, so that its point 14 does not 
touch the dividing wall 12. If the plug is pushed the whole way down, as 
shown in FIG. 2, but before extraction of the bellows-shaped section 2 of 
the case, then said point 14 of the rod 13 will perforate the partition 
wall 12, so that the solvent in compartment 6, when the case section 2 has 
been extracted, can be squeezed up into the now profusely enlarged 
compartment 5, and the powder be dissolved by shaking the tube. When the 
tube has been pressed back to its original size and the plug 4 has been 
pulled out, the tube is ready for injection. 
In FIG. 2 the insert 7 is shown having a diameter slightly smaller than the 
interior diameter of the tube case. In fact the insert fits tightly into 
the tube case. As it appears from the same figure the bottom of the insert 
12 may be arched upwards or shaped as a truncated cone. This gives the 
bottom a certain rigidity. 
As it will appear from the above explanation the partition 12 is fairly 
near the tube's tip 3 when the tube is in its compressed state (FIG. 1), 
whether said partition wall in a well-known manner is directly attached to 
the tube case or is the bottom of an insert as in the embodiment shown, 
and therefore it will not impede the compression of the tube.