Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1998-07-09
2001-05-15
Sykes, Angela D. (Department: 3762)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S117000, C604S071000, C604S239000, C604S272000
Reexamination Certificate
active
06231540
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
The invention relates to an injection member for a jet spray injection device through which device a dose of medicine is administered for subcutaneous or intramuscular injection.
It is often wanted to perform a subcutaneous injection of a medicine dose. The medicine is deposited in the subcutis tissue from where it subsequently finds its way to the blood. Especially diabetics have to frequently inject themselves with insulin to keep their blood glucose content under control. For this purpose a number of injection devices exist.
A conventional injection device comprises a syringe which is provided with a needle which has a length enabling it to penetrate the cutis and enter the subcutis where a dose of medicine is deposited by being pressed from the syringe out through the needle.
However, many people are reluctant to prick themselves with needles and although needles are made very thin and short an injection may still engender the above mention reluctance which may promote a user to cut down the number of injections to a level beyond the warrantable.
To overcome this needle phobia of the patient and to further reduce pain, various jet injection systems have been developed. Such jet injection systems have no needle, but instead use a spray nozzle through which the medicine is sprayed to give the medicine a speed enabling it to penetrate the cutis and be dispersed in the subcutis. However, dosing is difficult, in part due to the anatomical condition of the skin (cutis) where the first layer (stratum corneum) consists of dead keratinized cells. The layer is much more resistant to water penetration than to lipid penetration, and it forms a strong mechanical barrier, especially considering the thickness of the layer, which has a mean of 0.1 mm on the most of the body (thin skin). The stratum corneum is enlarged in a few specific areas (thick skin): e.g., the hand and the foot sole areas where injection normally is avoided. Beneath the stratum corneum lie various other layers of epidermis, with living skin cells, blood vessels, sensory nerve endings etc. Three epidermis is followed by the dermis which is mainly connective tissue. Then follows the subcutis (mostly adipose tissue and connective tissue). The size of the subcutis is very variable in the individual person and between persons. When using spray injection it is difficult to estimate how much of the medicine glances off from the dead cells at the skin surface and how much actually reaches the subcutis.
BRIEF SUMMARY OF THE INVENTION
It is an object of the invention to provide an injection member for a jet spray injection device by which injection member the above mentioned drawbacks are overcome.
An injection member according to the invention is characterised in that it comprises a skin-penetrating member having a length in the range from 0.05 mm to 6 mm combined with a jet spray nozzle.
The use of the injection member according to the invention will reduce the risk of damaging the often very large medicine molecules during the passage through of the skin. Furthermore, less injection force needs to be applied and a more precise definition of the injection depth is possible so that superficial or too profound deposits is avoided. The size of the skin-penetrating member may be so small that it does not cause pain but is, if at all, felt as a small pressure on the skin. The risk for bleeding due to needle trauma is also reduced to almost zero.
According to the invention the skin-penetrating member may have a length in the range 0.05 mm to 4 mm, preferably between 0.3 mm and 2 mm. Such skin-penetrating members will be too short for conventional injection but may be used for jet injection to ensure that the jet has not to penetrate the stratum corneum.
In a preferred embodiment of the invention, the skin-penetrating member has a length from 0.05 mm to 0.3 mm, more preferred 0.1 mm to 0.2 mm. With this length the skin-penetrating member is long enough to weaken or penetrate the stratum corneum but not long enough to cause significant contact with the layer of living cells beneath stratum corneum, and insertion in the subcutis is impossible. Neither will the skin-penetrating member be able to get in contact with the sensory nerve endings located in the cutis. Medicine delivered as a jet through the skin-penetrating member will not partly glance off from the keratine layer, and thus the injected dose will be more accurate. Moreover the risk of pain release as seen with conventional subcutaneous needles will be minimized to that of the jet stream.
The shape of the skin-penetrating member may be that of a conventional needle, but it may have other forms and the peripheral end may be sharp or blunted. The inner diameter of the skin-penetrating member may be from 0.1 mm to 3 mm.
According to the invention the injection member may appropriately be a changeable unit which can be mounted on a jet injection syringe. This will allow the injection ember to be changed each time an injection has been made. Also the skin-penetrating member ay at each injection be chosen to have a length suited for the user and the intended point of injection.
By a number of measurements it is found that the thickness of the cutis and subcutis lies in the intervals described in the following table. The mean values may be seen as the values valid for the preferred injection zones.
Females
Males
min
max
mean
min
max
mean
cutis
1.1
3.6
1.7
1.2
4.1
2.3
subcutis
4.5
30.8
12.1
2.3
26.9
7.2
sum
5.6
34.4
13.8
3.5
31.0
9.5
According to the invention the injection member may be provided with an array of'short skin-penetrating members. Hereby a better distribution of the injected liquid is ensured.
REFERENCES:
patent: 2704542 (1955-03-01), Scherer
patent: 3507276 (1970-04-01), Burgess
patent: 3964482 (1976-06-01), Gerstel et al.
patent: 4235234 (1980-11-01), Whitney et al.
patent: 5505694 (1996-04-01), Hubbard et al.
patent: 5569189 (1996-10-01), Parsons
patent: 5954689 (1999-09-01), Poulsen
patent: 6056716 (2000-05-01), D'Antonio et al.
Bianco Patricia
Novo Nordisk A S
Sykes Angela D.
Zelson, Esq. Steve T.
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