U.S. patent application number 10/659610 was filed with the patent office on 2004-03-11 for pellet implant system for immediate and delayed release of antiparasitic drug.
Invention is credited to Kenison, Dale C., Spurlin, Stanford R..
Application Number | 20040047888 10/659610 |
Document ID | / |
Family ID | 22590937 |
Filed Date | 2004-03-11 |
United States Patent
Application |
20040047888 |
Kind Code |
A1 |
Kenison, Dale C. ; et
al. |
March 11, 2004 |
Pellet implant system for immediate and delayed release of
antiparasitic drug
Abstract
A parasiticidal pellet system which delivers both immediate and
long term control of parasite infestation in an animal as part of a
single implant procedure. The system includes an implanter
apparatus for subcutaneously implanting parasiticidal pellets in an
animal through the bore of a hypodermic needle which is operably
coupled to a pellet magazine, and a plurality of pellets sized to
be implanted through the needle and positioned in the magazine for
selective alignment of a pellet with the needle. The pellets
include at least one immediate release parasiticidal agent first
dose pellet and at least one extended release parasiticidal agent
dose second pellet. The combined pellets are packaged in the
magazine in sequential order for simultaneous delivery of an
immediate dose and an extended dose as part of a single injection.
The system permits both immediate and sustained release of an
effective dose of the parasiticidal agent, in order to control
present parasite infestation and to prevent reinfestation for a
period of up to about 150 days.
Inventors: |
Kenison, Dale C.; (Overland
Park, KS) ; Spurlin, Stanford R.; (Lenexa,
KS) |
Correspondence
Address: |
SONNENSCHEIN NATH & ROSENTHAL LLP
P.O. BOX 061080
WACKER DRIVE STATION, SEARS TOWER
CHICAGO
IL
60606-1080
US
|
Family ID: |
22590937 |
Appl. No.: |
10/659610 |
Filed: |
September 10, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10659610 |
Sep 10, 2003 |
|
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09163646 |
Sep 30, 1998 |
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6645192 |
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Current U.S.
Class: |
424/405 ; 514/29;
604/500 |
Current CPC
Class: |
A61K 9/1652 20130101;
A61K 9/0024 20130101; A61P 33/10 20180101; A61P 33/14 20180101;
A61M 37/0069 20130101; A61K 9/1635 20130101 |
Class at
Publication: |
424/405 ;
514/029; 604/500 |
International
Class: |
A01N 043/04; A01N
025/00; A61M 031/00 |
Claims
What is claimed and desired to be secured by Letters Patent is as
follows:
1. A method for providing immediate and long term control of
parasite infestation in an animal; said method comprising: (a)
providing an implanter apparatus for implanting parasiticidal
pellets in an animal's ear through the bore of a hypodermic needle
which is operably coupled to a pellet magazine; (b) loading the
pellet magazine with at least one immediate release parasiticidal
agent pellet dose and at least one extended release parasiticidal
agent pellet dose; (c) inserting the hypodermic needle under the
skin of an animal's ear and injecting said at least one immediate
release pellet dose and said at least one extended release pellet
dose; and (d) withdrawing the hypodermic needle from under the skin
of the animal's ear thereby leaving said at least one immediate
release pellet dose and said at least one extended release pellet
dose beneath the skin of the animal's ear.
2. The method according to claim 1 wherein said immediate release
and said extended release parasiticidal agent pellet doses
separately comprise a parasiticidal agent selected from the group
consisting of avermectins, milbemycins, milbemycin oximes,
fenbendazoles, lufenerons, derivatives and mixtures thereof.
3. The method according to claim 2 wherein said parasiticidal agent
comprises an avermectin selected from the group consisting of
ivermectin, doramectin, moxidectin, eprinomectrin, abamectin,
derivatives and mixtures thereof.
4. The method according to claim 1 further comprising the step of
providing a plurality of discrete pellet doses.
5. The method according to claim 4 further comprising the step of
providing at least one discrete immediate release dose in a first
pellet and at least one discrete extended release dose in a second
pellet.
6. The method according to claim 1 further comprising the steps of:
(a) inserting the hypodermic needle under the skin of an animal's
ear and injecting said at least one immediate release pellet dose;
(b) maintaining the hypodermic needle in place under the skin of
the animal; and (c) sequentially injecting said at least one
extended release pellet dose.
7. In a method of administering a subcutaneous implant to an
animal, the improvement comprising the step of injecting an implant
for retention under the skin of an animal's ear, said implant
comprising an immediate release parasiticidal agent dose and an
extended release parasiticidal agent dose in a single
injection.
8. A method for providing immediate and sustained parasiticide
release in an animal comprising the steps of: (a) providing an
implanter apparatus for implanting pharmaceutical pellets in an
animal through the bore of a hypodermic needle which is operably
coupled to a pellet magazine; (b) loading the pellet magazine with
an immediate release parasiticidal agent pellet dose and an
extended release parasiticidal agent pellet dose; (c) inserting the
hypodermic needle under the skin of the animal's ear and
selectively injecting the immediate release pellet dose; (d)
simultaneously with the step of paragraph (c) also injecting the
extended release parasiticidal agent pellet dose; and (e)
withdrawing the hypodermic needle from under the skin of the animal
while leaving both of said immediate release and extended release
doses beneath the skin of the animal's ear.
9. In an implant adapted for subcutaneous implantation in an
animal's ear by an implanter apparatus through the bore of a
hypodermic needle which is coupled to a pellet magazine, the
improvement comprising: (a) said implant including a plurality of
pellets sized and shaped to be implanted through the needle and
positioned in the magazine for selective alignment of the implant
with the needle; and (b) the pellets of a single implant including
both at least one immediate release parasiticidal agent pellet dose
and at least one extended release parasiticidal agent pellet
dose.
10. The implant according to claim 9 wherein the pellets are
packaged in the magazine in sequential order for delivery of an
immediate release parasiticidal agent dose in at least one discrete
pellet followed by an extended release parasiticidal agent dose in
at least one pellet for subcutaneous placement in a single
injection.
11. The implant according to claim 10 wherein said immediate
release and said extended release parasiticidal agent pellet doses
separately comprise a parasiticidal agent selected from the group
consisting of avermectins, milbemycins, milbemycin oximes,
fenbendazoles lufenerons, derivatives and mixtures thereof.
12. The implant according to claim 11 wherein said parasiticidal
agent comprises an avermectin selected from the group consisting of
ivermectin, doramectin, moxidectin, eprinomectrin, abamectin,
derivatives and mixtures thereof.
13. The implant according to claim 10 wherein said immediate
release parasiticidal agent pellet dose further comprises a
disintegration agent and said extended release parasiticidal agent
pellet dose further comprises a bioerodible matrix.
14. An implant for subcutaneous implantation in an animal's ear
comprising: (a) at least one discrete immediate release
parasiticidal agent pellet dose; and (b) at least one discrete
extended release parasiticidal agent pellet dose, said pellet doses
being combined in a single unit and being injectable into an animal
at the same time for implantation side by side into the same
site.
15. The implant according to claim 14 further comprising an
excipient and wherein each of said immediate release and said
extended release parasiticidal agent pellet doses separately
comprise a parasitical agent selected from the group consisting of
the avermectins, milbemycins, milbemycin oximes, fenbendazoles,
lufemerons, derivatives and mixtures thereof.
16. The implant according to claim 15 wherein said parasiticidal
agent comprises an avermectin selected from the group consisting of
ivermectin,, doramectin, moxidectin, eprinomectrin, abamectin.
derivatives and mixtures thereof.
17. The implant according to claim 14 wherein each immediate
release parasiticidal agent pellet dose further comprises a
disintegration agent and each extended release parasiticidal agent
pellet dose further comprises a bioerodible matrix.
18. An implant adapted for subcutaneous implantation in an animal's
ear comprising: an immediate release pharmaceutical composition
comprising at least one parasiticidal agent and a disintegration
aid; and an extended release pharmaceutical composition comprising
at least one parasiticidal agent and a binding agent.
19. The implant of claim 18, said parasiticidal agent being
selected from the group consisting of avermectins, milbemycins,
milbemycin oximes, fenbendazoles, lufenerons, derivatives and
mixtures thereof.
20. The implant of claim 19, said parasiticidal agent comprising an
avermectin selected from the group consisting of ivermectin,
doramectin, moxidectin, eprinomectrin, abamectin, derivatives and
mixtures thereof.
21. The implant of claim 18, said immediate release pharmaceutical
composition comprising from about 25-125 mg of said parasiticidal
agent.
22. The implant of claim 18, said extended release pharmaceutical
composition comprising from about 50-175 mg of said parasiticidal
agent.
23. The implant of claim 18, said disintegration aid being selected
from the group consisting of magnesium stearate, croscarmellose
sodium, microcrystalline cellulose, derivatives and mixtures
thereof.
24. The implant of claim 18, said binding agent being selected from
the group consisting of lactose, polyethylene glycol, magnesium
stearate, cellulose, ethylcellulose, polymeric supports, binders,
coloring agents, derivatives and mixtures thereof.
25. The implant of claim 18, said extended release pharmaceutical
composition having a delivery period of at least 120 days.
26. A method for providing immediate and extended control of
parasite infestation in an animal comprising the steps of: (a)
providing an implant adapted for subcutaneous implantation in an
animal's ear comprising an immediate release pharmaceutical
composition comprising at least one parasiticidal agent and a
disintegration aid, and an extended release pharmaceutical
composition comprising at least one parasiticidal agent and a
binding agent; and (b) implanting said implant into an animal's
ear.
27. The method of claim 26, said parasiticidal agent being selected
from the group consisting of avermectins, milbemycins, milbemycin
oximes, fenbendazoles, lufenerons, derivatives and mixtures
thereof.
28. The method of claim 27, said parasiticidal agent comprising an
avermectin selected from the group consisting of ivermectin,
doramectin, moxidectin, eprinomectrin, abamectin, derivatives and
mixtures thereof.
29. The method of claim 26, said immediate release pharmaceutical
composition comprising from about 25-125 mg of said parasiticidal
agent.
30. The method of claim 26, said extended release pharmaceutical
composition comprising from about 50-175 mg of said parasiticidal
agent.
31. The method of claim 26, said disintegration aid being selected
from the group consisting of magnesium stearate, croscarmellose
sodium, microcrystalline cellulose, derivatives and mixtures
thereof.
32. The method of claim 26, said binding agent being selected from
the group consisting of lactose, polyethylene glycol, magnesium
stearate, cellulose, ethylcellulose, polymeric supports, binders,
coloring agents, derivatives and mixtures thereof.
33. The method of claim 26, said extended release pharmaceutical
composition having a delivery period of at least 120 days.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention is broadly concerned with a pellet
implant system that simultaneously administers both an immediate
parasiticidal dosage first component and a long term release
parasiticidal dosage of a second component placed in subcutaneous
pellets in order to control internal and external parasites in
domesticated and wild animals. More particularly, it is concerned
with an implanter having a pellet magazine containing parasiticidal
pellets with an associated injection needle, as well as structure
permitting injection of the pellets from the magazine through the
needle for implantation under the skin of an animal. The pellets
are formulated to deliver two separate doses simultaneously. The
first dose is a parasiticidal dose which is immediately available
for absorption. The second dose is a parasiticidal dose which is
available for sustained absorption through bioerosion and diffusion
over an extended period of time.
[0002] The importance of parasite control in animals used for meat
and other agriculture production, recreation and companionship is
well recognized. Meat, milk and fiber producing animals, such as
suckling, growing, grazing and feed lot cattle, domesticated swine,
sheep, goats, poultry and companion animals such as horses, dogs
and cats all serve as hosts for a large number of internal and
external parasites. The presence of such parasites is known to
reduce overall production in animals producing meat and other
agricultural productions. In the case of companion and recreational
animals, the presence of parasites can lead to discomfort, impaired
health and performance, and even death.
[0003] Wild animal populations infested with parasites may
experience substantial harmful effects as well as reduced
reproductive efficiency. Such harmful effects are of particular
concern in populations of endangered species, since it may impair
attempts to reintroduce the species into an environment or to build
the species population up to a level which can be easily sustained
by natural growth. Endangered mammalian species which are
maintained or managed in limited area preserves such as game
preserves, animal parks, national parks or wildlife areas as well
as zoo animals which are maintained in confined areas, are
particularly susceptible to parasite infestation since they inhabit
areas substantially smaller than their natural habitats, with
denser populations of both parasites and their animal hosts.
[0004] Implant technology, that is to say, subcutaneous implant of
pharmaceuticals and medical devices, is now well accepted and
widespread in the fields of animal health and production
enhancement and human health. Many types of biologically active
compounds, including hormones, vitamins, antibiotics,
antiinflammatory agents, vaccines and biocides are administered as
solid compressed pellets which are injected by an implanter
equipped with a hypodermic needle. The needle is used to make a
small self-sealing and noncoring implant-receiving puncture beneath
the skin at a suitable location on the body of the animal. Small
pellets of the bioactive compound are forced through the needle and
left under the skin as the needle is removed. The ears are a
preferred site for pellet implantation in livestock such as cows,
pigs and sheep. Implanted ears are commonly discarded in
slaughtering, so that no unabsorbed pellet residue will end up in
food products intended for consumption by humans or domestic
animals.
[0005] The pellets are normally implanted in farm animals while the
animal is confined in a chute. An ear is grasped in one hand, and
an implanter device having a large hypodermic needle is used to
puncture the hide and subcutaneously inject a pellet dose into an
implant-receiving puncture. Implantation must be done carefully to
ensure that the pellets are properly placed and that no portion of
the pellet remains extending from the puncture outside the hide.
The procedure must also be carried out quickly since the animals
are not entirely cooperative and may shake their heads to free the
held ear.
[0006] U.S. Pat. No. 5,522,797 (hereinafter "the '797 patent"), and
entitled Slide Action Veterinary Implanter, which patent is hereby
incorporated by reference, discloses an implanter which employs a
slide action mechanism to retract an impeller, store an impeller
driving force in a spring in cooperation with a latch mechanism,
reset a trigger, and advance a pellet magazine, all by a single
trigger actuated reciprocation of the slide mechanism. Operation of
the trigger also forces the pellets from the magazine through the
needle and under the skin of the animal.
[0007] Efficient implants such as that taught in the '797 patent
permit rapid sequential injection of many animals in a single
session and make implant technology particularly well-suited for
administration of parasiticides while the animals are confined for
ear tagging, branding, veterinary procedures or the like. Even
where only a single animal is to be treated, implantation offers a
particularly safe method for administering certain biocides, so as
to allow a user to avoid biocides that could be toxic if ingested
by the animal, for example by licking off residue left on its own
hide or fur or on that of another animal following treatment by
dipping, spraying or dusting.
[0008] A number of effective compounds are available for internal
and external parasite control, including the polyketide
avermectins, the milbemycins and milbemycin oximes, fenbendazole
and lufeneron. The most commonly used avermectins are ivermectin,
doramectin, moxidectin, eprinomectrin and abamectin. However, such
parasiticidal compounds have not previously been available in
implantable pellet formulations which provide for immediate as well
as extended release of the parasiticide.
[0009] Previous avermectin and milbemycin implants such as
disclosed by Hepler in PCT application WO 9625852 and by Wallace in
U.S. Pat. No. 4,847,243 do not provide prolonged controlled release
of the parasiticide dose. Consequently, additional parasiticidal
pellets must be periodically implanted in host animals to treat
parasites in the immediate environment of the host animal.
[0010] This requirement for periodic readministration is not only
cumbersome and inefficient, it increases the likelihood that a dose
will be delayed or missed altogether and that parasites endemic to
the environment will reinfest the host animal. Moreover, each such
procedure subjects the animal to stress and risk of infection at
the injection site.
[0011] A variety of techniques are currently employed to obtain
sustained release of parasiticides. Oral boluses are formulated in
double walled cylinders, with layers of racemates of active
ingredients, with outer and inner layers having polymer coatings,
with wax and fat to retard dissolution, and with heat responsive
carriers.
[0012] While such measures provide for sustained release of
parasiticides over many hours, they do not obviate the need for
periodic redosing. Effective parasite control requires prolonged
sustained release for periods of up to several months in order to
interrupt the parasite life cycle in the environment of the host
animal.
[0013] Accordingly, there is a need for a system which delivers
subcutaneously pellet implants of varying controlled release
parasiticidal dosages to provide immediate as well as sustained
release of the parasiticide for a period of up to several months,
and which does so without requiring periodic redosing.
BRIEF SUMMARY OF THE INVENTION
[0014] The present invention resolves the problems previously
outlined and provides a greatly improved parasiticidal pellet
system which delivers separate doses of both immediate and long
term control of parasite infestation in an animal as part of a
single implant procedure wherein the immediate dose is sufficient
to kill pests already present in the animal and the long term dose
is sufficient to prevent reinfestation.
[0015] Broadly speaking, the pellet system includes an implanter
apparatus for subcutaneously implanting parasiticidal pellets in an
animal through the bore of a hypodermic needle which is operably
coupled to a pellet magazine, and a plurality of pellets sized to
be implanted through the needle and positioned in the magazine for
selective alignment of a pellet with the needle. The pellets
include at least one immediate release parasiticidal agent first
dose pellet and at least one extended release parasiticidal agent
dose second pellet. The combined pellets are packaged in the
magazine in an individual dosing chamber for simultaneous delivery
of an immediate dose and an extended dose as part of a single
injection. Advantageously, the system permits both immediate and
sustained release of an effective dose of the parasiticidal agent,
in order to control present parasite infestation and release
sufficient agent over to prevent reinfestation for a period of up
to about 150 days. The immediate and sustained release agents may
be the same or different parasiticidal agents with the principal
difference between the agents being that the immediate agent is
formulated to completely release into the system of the animal very
quickly after implanting to provide a sufficient systemic amount of
the immediate agent to kill pests that are currently in the animal
and the sustained agent is formulated in a slow release matrix that
slowly releases the sustained agent over a comparatively long time,
for example about 150 days, in a sufficient amount to systemically
prevent reinfestation of the animal.
OBJECTS AND ADVANTAGES OF THE INVENTION
[0016] The principal objects and advantages of the present
invention include: providing a multicomponent parasiticidal pellet
system; providing a pellet system for immediate as well as
sustained delivery of a parasiticide in order to kill both internal
and external parasites present on an animal and which may reinfest
the animal in the future; providing a pellet system which includes
an implanter apparatus for subcutaneously injecting pellets in an
animal through the bore of a hypodermic needle which is operably
coupled to a pellet magazine and simultaneously introduces separate
immediate and extended release parasiticidal pellet doses;
providing such a system and method which permits injection of
predetermined doses of each of a parasiticide for immediate release
and a parasiticide for extended release in a single injection;
providing such a system and method which permits subcutaneous
injection of both an immediate release parasiticidal dose and an
extended release parasiticidal; providing such a system and method
which permits an operator to selectively inject an extended release
parasiticidal dose into the needle; providing such a system and
method which permits serial injection of large numbers of animals
in a single session; providing such a system and method which may
employ a wide range of parasiticidal agents for use in control of
infestation; providing such a system and method which is simple and
efficient and economical to manufacture, which effectively prevents
reinfestation of the animal for a period of up to about 150 days
and which is particularly well-adapted for its intended
purpose.
[0017] Other objects and advantages of this invention will become
apparent from the following description taken in conjunction with
the accompanying drawings wherein are set forth, by way of
illustration and example, certain embodiments of this
invention.
[0018] The drawings constitute a part of this specification and
include exemplary embodiments of the present invention and
illustrate various objects and features thereof.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWING
[0019] FIG. 1 is a fragmentary perspective view of a cow, an
implanter apparatus in accordance with the present invention, and
an apparatus operator;
[0020] FIG. 2 is an enlarged, fragmentary cross-sectional view,
taken along line 2-2 of FIG. 1, illustrating a hypodermic needle
with pellets inside the needle being inserted into an ear of the
cow;
[0021] FIG. 3 is an enlarged, fragmentary cross sectional view
similar to FIG. 2, illustrating subcutaneous placement of a stack
of pellets by the implanter into the ear of the cow.
DETAILED DESCRIPTION OF THE INVENTION
[0022] As required, detailed embodiments of the present invention
are disclosed herein; however, it is to be understood that the
disclosed embodiments are merely exemplary of the invention, which
may be embodied in various forms. Therefore, specific structural
and functional details disclosed herein are not to be interpreted
as limiting, but merely as a basis for the claims and as a
representative basis for teaching one skilled in the art to
variously employ the present invention in virtually any
appropriately detailed structure.
[0023] Referring now to the drawing, the reference numeral 10
represents a pellet implantation system in accordance with the
invention. The implantation system 10 broadly includes a slide
action implanter apparatus 12 which is used to implant solid form
bioactive compounds in various formulations, such as immediate
release compressed pellets 14 and extended release compressed
pellets 16 (FIG. 2) from a magazine strip 18 into an animal 20
through a hypodermic needle 22. The needle 22 is utilized by an
operator 24 to create an opening 26 that produces an implant
receiving puncture 28 in the animal 20.
[0024] A suitable implanter apparatus 12 is illustrated and
described in detail in the '797 patent, and generally includes a
housing 30 having a finger grip 32 with a trigger assembly 34
pivotally mounted therein. An impeller 36 is slidably mounted
within the housing 30 in alignment with an interior bore 38 of the
needle 22 and aligned chambers 40 of the loaded pellet magazine
strip 18. The needle 22 is used to puncture through skin or hide 42
of an animal's ear 44 at the opening 26, and the trigger 34 is
squeezed toward the grip 32 of the housing 30 to initiate injection
of the pellets 14 and 16 and so as to cause the impeller 36 to be
urged through the magazine chamber 40 and needle bore 38, thereby
forcing the pellets 14 and 16 through the bore 38 of needle 22 and
into the puncture 28 in the ear 44.
[0025] Each magazine strip 18 of the implanter 12 typically
contains multiple parallel aligned pellet doses stored in
corresponding pellet chambers 40, which are connected by
interconnecting webs 46. The chambers 40 are slightly conical in
shape and are arranged in a side-by-side parallel relation. The
chambers 40 may have internal frictional formations such as beads
or posts (not shown) to retain the pellets 14 and 16 therein prior
to insertion and which can be easily bypassed by application of
pressure to the trigger 34. A plurality of strips 18 can be
connected in end-to-end relation to increase the implanting
capacity before the implanter 12 requires reloading. When the
pellets 14 and 16 in an individual magazine strip 18 are exhausted,
the empty strip 18 can be detached from the remaining strips 18
located in the implanter 12 and discarded.
[0026] In the present embodiment, each pellet chamber 40 is loaded
with a single immediate release parasiticidal agent dose pellet 14
and five extended release parasiticidal agent dose pellets 16. The
pellets 14 and 16 are composed of an effective amount of one or
more parasiticidal agents, formed into a compressed pellet in
conjunction with one or more excipients.
[0027] A wide range of active ingredients may be employed as
parasiticidal agents, for example, the polyketide avermectins, such
as ivermectin, doramectin, moxidectin, eprinomectrin and abamectin,
the milbemycins and milbemycin oximes, fenbendazole and lufeneron.
As used herein the term parasiticide is intended to include
parasiticides as noted above and other compositions that operably
function under the present invention like parasiticides in
combating and preventing reinfestation by internal and external
parasites and which may be used internally in the particular
species of animal to be treated by the invention. It is noted that
the amount of parasiticidal agent required to produce the desired
treatment varies with respect to the species and size of the animal
to be treated. For example, when treating cattle the immediate
release pellet preferably contains between about 25 and 125
milligrams of ivermectin and the sustained release combined pellets
contain between about 50 and 175 milligrams of ivermectin.
Parasiticidal agents having extended circulatory half-lives, such
as ivermectin, are particularly preferred.
[0028] The pellets are uniquely and separately formulated so as to
be biodegradable in the target animal to the control release of the
parasiticide at different rates. The extended release pellets 16
are formulated to combine an effective dose of a parasiticidal
agent such as ivermectin, with biding agent excipients that
lengthen the implant delivery period by extending pellet 16
integrity and limiting pellet hydration by extracellular fluid
entry into the pellet 16. In this manner, the extended
pharmacokinetics of the parasiticidal agent, delayed bioerosion of
the pellet, and delayed diffusion of the agent dose cooperatively
result in an extended release pellet which makes available for
absorption an effective dose of parasiticidal compound over a
period of up to 150 days.
[0029] Any number of excipients may be employed in the extended
release pellets 16, including lactose, polyethylene glycol, as sold
under the trademark Carbowax.RTM., by Union Carbide, magnesium
stearate, cellulose and its derivatives, especially ethylcellulose
as sold under the trademark Ethocel.RTM. by Dow, polymeric
supports, binders and coloring agents.
[0030] The immediate release pellets 14 make the parasiticide
available for absorption into the bloodstream of the animal
immediately and may include the previously listed excipients as
well as disintegration aids such as magnesium stearate and
croscarmellose sodium, especially as sold under the trademark
Ac-Di-Sol.RTM. by FMC and microcrystalline cellulose, especially as
sold under the trademark Avicell.RTM. by FMC.
[0031] Each intermediate release pellet 14 is formulated to
dissolve and enter the animal's blood system (systemically) within
a few days, preferably within hours of injection. The extended
release pellets 16 are formulated to release active parasiticide
into the animal's blood system slowly and continuously over a
period of many days, for example about 150 days, in order to
sustain sufficient parasiticide systemically in the animal being
treated to prevent reinfestation by undesirable pests.
[0032] The compressed pellets 14, 16 can be produced inexpensively
and in large quantities by a variety of conventional manufacturing
equipment.
[0033] In the illustrated embodiment, one pellet 14 incorporates an
immediate release parasiticidal dose and the other five pellets 16
incorporate an extended release parasiticidal dose. It is foreseen
that the number of pellets within an individual dosing chamber 40
within a magazine 18 for each release formulation within may vary,
depending on the desired dose of parasiticide to be delivered. As
an example, the extended release pellets 16 may number one or many,
such as the illustrated five.
[0034] Each magazine chamber 40 is prefilled with a preferred
number of discrete pellets 14 and 16, each containing a
parasiticidal dose in a compressed pellet formulation designed
respectively for immediate and extended release, the chamber 40
containing at least one immediate release pellet 14 and one
extended release pellet 16. The magazine strip 18 is preferably
loaded onto implanter housing 30 in an orientation so that the
immediate release parasiticidal pellet will be delivered first,
followed by the extended release parasiticidal pellets 16.
[0035] In use, an operator grasps the implanter 12 by the grip 32
and urges the needle 22 into the hide 42 and under the skin of the
target animal 20 to make the implant receiving puncture 28. The
puncture 28 shown in FIG. 2, is approximately half complete and is
complete in FIG. 2. The operator 24 depresses the trigger member
34, thereby propelling a pin 48 of the impeller member 36 forwardly
through an aligned magazine chamber 40, forcing the pellets 14 and
16 through the needle bore 38 and into the implant receiving
puncture 28. The operator 24 then withdraws the needle 22, leaving
the pellets 14 and 16 in the implant receiving puncture 28.
[0036] The bioerodible excipient disintegration aids included in
the formulation of immediate release pellet 14 allows the pellet 14
to immediately make available for systemic absorption an effective
dose of a parasiticidal compound, such as ivermectin. The long
circulatory half-lives of such compounds ensures protection of the
animal against parasites for up to 30 days. The binders included in
the extended release pellets 16 cause delayed bioerosion of the
pellets and diffusion of the effective dose of the parasiticidal
compound for absorption into the bloodstream of the animal over an
additional period of up to 120 days. This multicomponent
formulation lengthens the pellet delivery period for the
parasiticidal compound dose so that effective blood levels of the
parasiticidal compound are maintained for periods of up to 150
days. In this manner, the internal and external parasites of the
host animal are eliminated, and the animal is protected from
reinfestation until the parasite life cycle in the environment has
been interrupted and persistency, that is to say, repeated
reinfestation of the animal with parasites endemic to the
environment is eliminated.
[0037] Advantageously, the magazine strip 16 may be loaded for
selective injection of any number of immediate release pellets 14
or extended release pellets 16 in order to obtain delivery of a
selected dosage by each formulation tailored to the species,
weight, age or sex in a wide variety of animals. Where a number of
pellets of each formulation of pellets 14 and 16 are to be
delivered, the pellets may be alternated. In other embodiments,
both immediate and delayed release antiparasitic pellets 14 and 16
may be alternated in a stack of pellets of other pharmaceuticals,
for delivery through the implant receiving puncture 28.
[0038] The pellet system 10 of the present invention may be
employed efficaciously with cows, sheep, swine, goats, poultry,
horses, dogs, cats or any other suitable animal, including wild
animals and humans.
[0039] The following example is provided for the purpose of
illustrating the invention and is not intended to be limiting upon
the scope of the claims.
EXAMPLE 1
[0040] A quick release pellet is produced including 100 milligrams
of ivermectin in a quick release matrix of lactose and
microcrystalline cellulose as a disintegration aid. A set of five
sustained release pellets is formulated and formed containing a
total of 125 milligrams of ivermectin in a controlled and sustained
release matrix of polyethylene glycol. Thereafter, all six pellets
are implanted under the skin in the ear of a cow.
[0041] It is to be understood that while certain forms of the
present invention has been illustrated and described herein, it is
not to be limited to the specific forms or arrangement of parts
described and shown.
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