Note: Descriptions are shown in the official language in which they were submitted.
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INJECTION DART SYSTE~
Field of the Invention
The present invention relates to a dart cont~; n; ny
lS drug-delivery implants ~or insertion into the body of a subject,
such as an ~n;m~l, and a system for injecting the dart into the
subject.
~ackground O~ the Invention
~n;m~l s, particularly An;m~ls in the wild, have long
been injected with tranquilizers and other drugs through the use
o~ hypodermic darts propelled by means o~ a ri~le or similar
device. Such darts are constructed to lodge into the skin of the
~n; m~ 1 and to release their drug charge upon impact. The dart
needs to be removed from the ~n;m~l 8hortly after use, in order
to avoid infection or other injury to the ~n; mA 1
On the other hand, the need often exists to provide
drug treatment to an ~n; m~ 1 over extended periods o~ ~ime.
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Moreover, the druy may be of a type, such as a somatotropin,
which would be broken down by the ~nim~l 'S digestive system if
~m; n; ~tered with its food supply. United States Patent No.
5,266,325 gr~nt~ to Kuzma et al. on ~.~v~Ler 30, 1993 suggests
that drugs which need to be ~m;n;~tered over an ~t~n~A period
of time be provided in a su8t~;n~ relea8e drug-delivery imrl~nt
which is injected subcut~n~o~ y into the living tissues of the
subject. In accordance with Kuzma et al., the ;mrl~nt is
introduced into the subject through a c~nn~ of a large
hypodermic needle/syringe-like instrument, which is l~"oved from
the subject's body ;mm~ tely after injecting the implant.
However, this method of introducing drugs is unsatisfactory for
treating large groups of ~n;m~l S . For example, when treating
cattle or pigs in the field, it would not be convenient to
sterilize the hyro~rm;c needle or to use a new needle for each
~n;m~l, The danger therefore exists that a needle cont~m;n~ted
by one ~n;m~l could infect an entire group.
Another shortcoming of utilizing implants is that they
tend to shift in position. It therefore becomes very difficult,
if not impossible, to detect whether a subject has or has not
received an ;~rl ~nt Kuzma et al. suggests using a radioacti~e
material within the implant to permit detection. However, in the
field, this is not a satisfactory solution.
Broadly, it is an object of the present invention to
provide a system for introducing sustained release implants into
~nim~ls, which system avoids the shortcnm~ngs of known systems of
this type. It is specifically contemplated that the system be
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capable of introducing implants to a large group of ~nim~l S
without the risk of spreading infection or disease among them.
It is another object of the inv~nt;on that drug
~ cont~in;ng ;~r1~nt~ introduced into an ~n~m~l be c~r~le o~
rPm~;n;ng within the ~n~m~l for ~tPn~ periods Of t~me, while
their presence or the ~act o~ their having been intrnA--~e~ is
readily detectable, despite the depletion o~ the drug, and
without the use of complex instrl-m~nts.
It is yet another object of the present invention to
inject implants cont~n;ng one or more drugs into a subject
~n~ m~ 1 without the need to invasively penetrate the bodies o~
multiple ~n;m~l S with a common instrument.
It is also an object o~ the present invention to
provide a system and apparatus ~or introducing drug cont~in;ng
implants into the body o~ a subject, which qystem and apparatus
are simple, convenient, and reliable in use, yet relatively
inexpensive in construction.
In accordance with the present in~ention a dart
cont~;n;ng drug-delivery implants is provided, which can be
introduced and implanted readily in the subject's body at a given
site, for ~Y~mple~ subcutaneously in a pig's ear, without the use
o~ an instrument which invades the subject's body.
In accordance with a preferred embodiment o~ the
invention, the dart i9 of plastic material having a hollow
cylindrical body and a solid head, generally o~ a cylindrical
shape. The ~ace o~ the dart head has a 5coop shape and the
exposed edge sur~ace o~ the ~ace has a ~illet radius that starts
_
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at the tOp edge of the dart body and tapers downwardly and
forward from the hollow body. This forms a relatively long
narrow blade at the lower part of the head, the l~; n~ edge of
which is formed with a 5harp chi~el point, to provide f or
S penetration entry of the dart i~to the subiect'8 body.
Flexible st~h;li~;n~ wings are provided on either side
of the dart head. The stab;l;~; ng wings sweep outwardly and
backward toward the hollow cylindrical body and serve as a lock
or barb to prevent the dart ~rom being pulled out of the subject
once it has entered the subject's body part.
The dart's hollow body is preferably a coil of material
formed with a number of turns into a helix. This gives the body
a degree of flexibility to permit the dart's body shape to change
as it con~orms to the darted site of the subject's body. The
coil also makes the dart body compressible in a lengthwise
direction, to provide rigidity as the dart is inserted under
pressure into the subject. One or more implants, which may
contain the same or di~ferent substances, are located within the
hollow body. There is a passage through the dart head into the
body to provide ~luid cnmm~n~cation between the subject~s body
fluids and the implant. An end cap is frictionally fitted into
an opening at the rear of the body. The presence of the dart
injected into the subject may be determ,~d visually or by
palpation of the subject's darted body part (e.g. the ear).
It is a ~eature of the invention that a dart which is
pervious to body ~luids is provided which carries implants
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concaining one or more substances and that the dart is ltself
implan~ed directly into a subject, such as a pig.
A ~rthe~ feature o~ the invention is that a dart ~or
carrying one or more ;~rl~nt~ i8 per~ioU8 to body fluids and
includes a head with a blade ha~ing a sharp tip for penetrating
the subject's body. The dart body ~nt~;nR one or more implants
with subst~n~es to be relea~ed into the subject, so that the dart
is readily injected into the subject and carries the ;mnl ~nt~C
with it.
It is yet another feature of the invention that a dart
for carrying one or more implants into a subjec~ is pervious to
body fluids and has a body which is ~irm and rigid while being
inserted into the subject, yet may ~r~n~ in its lengthwise
direction, to become flexible after insertion into the subject.
It is a further ~eature o~ the in~ention that the
presence within a subject's body part of an injected dart
cont~;n;ng drug-delivery implants may readily be det~rm;n~
visually or by palpation of the subject's body part.
~rief Description of the Drawings
Other objects and advantages of the present invention
will become more apparent with re~erence to the following
specification in which:
Figure 1 is a top view of a preferred embodiment of a
dart in accordance with the invention;
Figure 2 is a side view of the dart shown in Fig. 1;
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Figure 3 is a sectional view taken along line 3-3 ana
looking in the direction of the arrows in the dart of Fig. 2;
Figure 4 is a ~ront view of the dart in Fig. 2;
Figure 5 i8 an enlarged fr~m~nt~y ~iew of a portion
of the dart of Fig. 1 showing the coils of the body C~ e89ed;
Figure 6 is an oYerall schematiC top view showing the
flexing of the dart body and the ~u~ esqion of the dart wings;
Figure 7 is an overall schematic side view s;m;l~r to
Fig. 6.
Figure 8 is a top view of a dart injection qystem or
applicator in accordance with the present invention.
Figure 9 is a left side view of the injection system of
Fig. 8, with parts shown in section to illustrate further
internal details of the system.
Figure 10 is a fra~~n~y sectional view taken along
line 9-9 in Fig. 8 after the ear of a subject has been captured
and showing the initial insertion of a dart; and
Figure 11 is a view S;m; 1 ~r to Fig. 9 showing the dart
completely inqerted.
D~tailed Description of the Invention
Referring to Figs. 1-7, the dart 10 includes a solid
head 20 generally having an overall cylindrical shape and a
hollow tubular body 30. The dart i9 preferably of a biologically
25 suitable plastic material such as a polycarbonate. The dart 10 r
is pre~erably made by injection molding and preferably in one
piece. The dart head 20 is a solid piece with a top face 22 that
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curves downwardly in a scoop shape ~rom a rear end 23 which is at
the beginning of the front end of body 30. From the head rear
end 23 there is a sur~ace edge l~ ng to concave radiu5 24
~xt~n~;n~ into a shallow, tapered sur~ace 26. This t~m;n~t~ in
an el~n~te~ projecting relatively narrow blade 27 having a
sharpened cutting edge 28 with a downward be~el 29. The bottom
sur~ace of blade 27 is curved. A plow 25 create~ a transition
from the narrow blade 27 (see Fig. 1) to the cylindrical dart
body 30 and ser~es a purpose to be descri~ed more fully below.
A pair of ~lexible wings 40 are formed on the outer
sur~ace o~ head 20 starting at the tapered surface 26. The wings
40 are swept back and overlie the front end of body 30. Wings 40
have a pointed leading edge 41 and lie in a horizontal plane, as
illustrated in Figs. 2-4, that is along the longitll~;n~l center
line o~ the dart body 30 and i5 parallel to a plane tangent to
the bottom of the body as shown in Fig. 2. As seen in Fig. 1,
each wing 40 has a relief slot 42 which is angled inwardly
rela~ive to the body that t~rm; n~ tes in a generally circular end
44. The slots 42 permit the wings to flex inwardly. This
prevents Rtress in the wings 40 when flexed upon insertion of the
dart into the subject.
Body 30 is a coil of se~eral turns 32 wound in a helix
to form a hollow tube. The turns 32 of the coil have opposing
stops 34 in the form of tabs. The tabs 34 ha~e the same curved
shape as the coil turns and are preferably spaced 90~ apart
around each side of each coil turn. The stops 34 of one coil
turn face those of the next ad~acent turn and the stops engage
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when the boay 30 is compressed lengthwise during insertion into
the subject. This is shown in Fig. 5.
One or more ;mrl~nt packages 50 (Figs. 1 and 3) are
located within the body 30 and cont~;n any type of nutritional or
S medicant supplement of desired dosage or a c~mh;n~t;on thereof.
The packages 50 are inserted into t~h~ r body 30 through the
open end of the body remote ~rom head 20. An end cap 54 with a
spherical radius i8 friction ~itted into the end of the body 30
remote from the head.
A hole 60 provide9 a ~mlnicating pas8age through head
20 f rom its top ~ace 22 to the inside of the body 30. Therefore,
when the dart is inserted into the subject, there is fluid
cnmmlln;cation between the body fluids of the subject to and with
the implant packages 50 for release of their contents into the
subject.
Figures 6 and 7 show the flexibility of the body 30 in
all directions. This permits the dart to conform to the
sub~ect's body, permitting norm~l movement of the darted body
part and a~oiding discomfort, irritations or rejection of the
dart by the subject's body. In Fig. 6, the wings 40 are shown in
the compressed state in dotted lines.
~ igure 8 is a plan view of a preferred embodiment of an
implant dart applicator or insertion system 90 embodying the
present in~ention, and Fig. 9 is a partially sectioned side view
illustrating ~urther details of the applicator system in use.
System 90 broadly comprises a main body 91, which includes a
chamber (not shown) adapted to receive a dart 10. At one end of
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g IPEA/I~S 2 2 QUG 1997
body 91, a platen 92 i9 positioned and retained by means of a
hinge member 98 so as to be pivotal relative to main body 91.*
Main body 91, opposite platen 92, also includes a propulsion
mechanism (not shown) is actualable to provide a propulsive force
S to ~he dart 10 inside main body 91, through a push bar 59, which
accelerates the dart towards platen 92. The propulsion mechanism
may be any type of conventional mechanism, but is pre~erably a
spring operated device which may be loaded and then released, as
by a trigger. AS best seen in Figs. 8-iO, main body 91 includes
a top part 93, which has ~. bore 97 in which dart 10 is
accelerated towards platen 92. ~y means o~ hinge member 98,
.~ platen 92 may be conveniently pivoted relative to main body 91 so
as to receive the ear (~) of the subject, into which the dart 10
is inserted. Ear (E) is then maint~;ne~ flat against the top of
platen 92 by means of arms 99, which engage it, and the ear is
formed into a 90~ bend in front of the exit (within the projected
perimeter) of bore 97. In this position, the ear is held captive
between platen 92 and leg 95.
The use of the dart 10 will now be explained. While
description is made relative to inserting the dart into the ear
of a pig, the dart can be used on other body parts or on other
types of subjects, including cattle, sheep, goats or other
livestock, or domestic or wild ~nlm~l S. In Figs. 9 and 10 .the
flat platen 92 lies opposite the top part 93 with a downwardly
2s extending leg 95. The pig's ear (E) has been captured between**
the platen 92 and leg 95 and i~ ret~ne~ in a ~lat po~ition on
top of the platen and ~ormed into a 90~ bend.
*(As used herein, the term platen refers to engagement means for
receiving and retaining a part of an animal body, ln accordance
with the present invention).
** an end 96 of ..~... .. .. ... .
~ ~~S~tEt
-
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In use, platen 92 is pre~erably o~set su~iciently
below the bore 97, which is parallel to the platen, to permit the
ear cartilage C to be aligned generally with or below the bottom
o~ bore 97 (i.e. outside the projected perimeter of the bore).
The dart is injected from bore 97 into the exposed top
sur-face of the ear (B). With the blade cur~ed ~ottom surface and
wings ~0 generally p~r~llel to platen 92, the dart is caused to
travel at a sufficient velocity to pierce the ear by propulsion
me~h~n;Qm 94. The dart's narrow, sharp chisel edge 28 cuts
through the skin of the ear (E) with min;m~l resistance. Slight
de~lection occurs when the front of the dart penetrates the skin.
As the dart travels ~urther under the skin, the radius 24 and
bottom plow 25 compensate to neutralize the downward ~orces.
Resistance encountered at the top edge 23 causes the dart to
lift, allowing it to travel across the upper surface o~ the
cartilage. ~ tl~ 24 and wings 40 guide the dart across the
cartilage, preventing blade 27 ~rom penetrating therethrough.
These details o~ these various me~h~nismq are explA;nP~ in more
detail below.
The shallow taper 26 at the inner end o~ the narrow
blade 27 and the radius 24 create a drag that li~ts the chisel
edge 28. Owing to its shape, plow 25 ~urther lifts and prevents
the cutting edge 28 ~rom penetrating cartilage. The bevel 29
continues deflecting the cartilage downwardly as the cutting edge
28 continues to cut through tissue during dart insertion. As a
result, the dart slides along the sur~ace o~ the cartilage as it
advances
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' 1
The wings 40 provide orientatiOn and rotational
stability for the dart as it is being inserted. They also
provide a locking ~eature once the -dart is inserted into the
subject. During insertion o~ the dart, the wings 40 are flexed
inwardly (8hown a8 dotted line8 in Fig. 6). A~ter in8ertion into
the ear, the wings reflex to their outward po8ition (as 8hown by
the solid lines in Fig. 6). The wings stabilize the dart a~ter
entry into the subject. This maintains proper alignment o~ the
dart and m;nim; 7es resistance at entry. A rear angle 46 on the
wings 40 (Fig. 6) causes the wings to engage body tissue and
spread out if the direction of the dart is reversed, thereby
creating the locking feature.
During dart insertion the coils 32 of the body are
compressed along the length o~ the body until the stops 34 engage
(as shown in Fig. 3), owing to the high accelerating velocity
imparted to the dart by the propulsion me~h~n;~m 94 (pre~erably
40-60 mph). This makes the dart collapse so as to be totally
rigid at the point o$ entry into the subject. With the dart in
the ear, there is cnmml~n;cation between the subject's body
fluids, e.g., blood, and the implant package 50 in body 30
through the head passage 60. This facilitates release o~ the
implant contents into the subject~s body.
After entry, upon any movement of the dart outwardly of
the subject, complete ~ wval of the dart is prevented by the
locking wings. The coil turns of the bocv can separate somewhat
as the ear moves so that the dart body is ~ore conformable to the
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ear. This also provides addi~ional cnmm~lnication between the
implants 50 and the subject's body fluids.
The spherical radiu9 shape of body end cap 54 provides
positi~e location with the matching spherical radius 57 (Fig. 10)
of a push bar 59 o~ the injection gun. This controls direction
and prevents the end cap 54 from side slipping as a dart
completes its travel into the ear.
Presence of the dart 10 in the subject can be detected
visually or by palpation of the darted site. It also
contemplated that the dart may include a small metal or magnetic
element to permit its detection by a metal or magnetic detector,
or the like. The dart may also include simple electronics to aid
in detection and identification.
The ~;m~n~ions of the dart 10 depend on a number o~
factors including, the ~m~n~ions o~ and the number of implants
cont~n~A, the type of subject, depth of the dart insertion,
insertion force needed to pierce the subject's skin etc. In the
example of the pig's ear, shown in Figs. 8 and 9 the dart 10 has
an o~erall length of about 45 mm and an outside diameter of about
7 mm.
Althouyh pre~erred forms o~ the invention have been
disclosed for illustrative purposes, those ~killed in the art
will appreciate that many additions, modifications, and
substitutions are possible without departing from the scope and
spirit of the invention as de~ined by the accompanying claims.
For example, although not as desirable, the dart 10 need not be
accelerated into the subject's body part by means of a propulsion
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13
device. Instead, it would be possible to make a small incision
in the subject's body part and to inject the dart into the body
~- part at low speed, as by operating the push bar 59 m~nll~l ly
