Intra-vaginal device for pigs

Details Intra-vaginal device for pigs Intra-vaginal device for pigs

2000-03-02

2002-09-03

Page, Thurman K. (Department: 1615)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Matrices

C424S484000, C424S422000, C424S430000, C424S423000, C424S425000

Reexamination Certificate

active

06444224

ABSTRACT:

This application is a 371 of PCT/N298/00064 filed May 27, 1998.
TECHNICAL FIELD
The present invention relates to improvements in and/or relating to intra-vaginal devices suitable for insertion and retention within pigs.
Intra-vaginal devices are frequently used to deliver an active substance into an animal.
BACKGROUND OF THE INVENTION
One use of intra-vaginal devices is to control the breeding cycles of animals. In this respect under the trade mark CIDR™ this company has manufactured a variery of devices for different animals including but not limited to cattle, sheep and pigs. The prior art devices of this company where they are to be used to synchronise oestrus have usually involved a spine (for example of a nylon plastics material) and an at least partially encasing silicone rubber matrix that has been impregnated with the active substance to be released, eg. progesterone.
The prior art device of this company marketed under the trade mark CIDR™ for pigs is detailed in New Zealand Letters Patent No. 230023 of which the Australian and U.S. equivalents are respectively numbers AUS620523 and U.S. Pat. No. 5,217,450. Appended hereto in the annexed drawings (
FIGS. 4A
to
4
C) are representations of such a prior art form from which it will be seen that a complex construction having wall engaging means at each end has been hitherto required in order to obtain a good measure of retention. In addition a complex construction for the non cervix end was required whereby the retention device at that end could be configured in three different ways, only one of which was its retention condition.
With pigs a great deal of care is required in order to ensure retention against spontaneous ejection and also against withdrawal by another animal.
The full content of the aforementioned patent specifications are hereby here included by way of reference.
The literature adequately explains the purposes for which such intra-vaginal devices containing progesterone or progestagens are delivered into female animals prior to mating.
In addition reference should be made, by way of example, to proprietary information released by suppliers of such active substances including, by way of example, VIRBAC in respect of its SUIPROST™ injectable product which is a synthetic prostaglandin for induction and synchronisation of farrowing in sows. The role however of such intra-vaginal devices usually is to be much earlier, namely, in respect of synchronising the onset of oestrus.
If both the control of oestrus cycle and high fertility are desired in the pigs then an intra-vaginal insert must deliver sufficient progesterone. We know that 15, 25, 50 mg per day (IM) for 14 days results in control of the oestrus cycle. However poor fertility results. We believe a dose of 100 mg per day for 14 days (IM) is desirable to both control the oestrus cycle and give normal fertility.
The present invention is therefore directed to porcine intra-vaginal devices that feature an improved retention characteristic (eg; across hymenal ring positioning and vestibular deployment of retention means), is of sufficient surface area as far as progesterone impregnated matrix or matrices is concerned and/or can deliver progesterone (at least) on both sides of the hymenal ring.
The amount of progesterone delivered by the said device preferably should be at least sufficient to maintain a plasma level of in excess of 4 ng/mL (as measured in an ovariectomised animal over at least a 14 day insertion period).
The present invention in one aspect is directed toward an intra-vaginal device which provides an alternative to the aforementioned prior art device. A preferred device is believed to provide a simplicity of moulding in at least some of its forms whilst providing in such preferred forms enhanced retention characteristics irrespective of the variations within the vaginal tracts of different pigs.
The present invention in other aspects relates to the control of the onset of oestrus and/or the maintenance or enhancement of fertility of pigs (particularly gilts).
BRIEF SUMMARY OF THE INVENTION
In a first aspect the invention consists in a porcine intra-vaginal device of a shape and size adapted to be positionable in the vaginal tract across the hymenal ring of a target animal (eg; a gilt) to extend to both sides of the hymenal ring of the animal, the device having or being (at least in part) a progesterone impregnated matrix or matrices to be on at least either side of the hymenal ring and being at least 150 cm
2
in total area.
Preferably said total area of progesterone impregnated matrix or matrices is greater than 172 cm
2
.
Preferably said matrix or matrices carry a progesterone load of at least 1.9 g.
Preferably said progesterone load is from 1.9 to 2.5 g.
Preferably, for gilts, said progesterone load is about 2.2 g.
Preferably said progesterone load is at least substantially all carried by the matrix or matrices within 1.2 mm of its release surface.
Preferably the device has a nylon (or equivalent) spine with an impregnated matrix formed thereabout.
Preferably the device has variable geometry means which deploy or is deployable upon insertion to retain the device in the vaginal tract. The variable geometry means may deploy on either or both sides of the hymenal ring.
Preferably the variable geometry means comprise at least one resilient wing or a form collapsible under the action of withdrawal.
Preferably the device is elongate of body with a wasted region to lie on the hymenal ring.
Preferably the matrix is a progesterone containing silicone rubber material which has been formed by injection of the uncured progesterone containing matrix as a liquid into a mould for a sufficient time to achieve a mould temperature or temperatures within the range of from 100° C. to 210° C. and a shape retaining at least partial cure thereof.
In a second aspect the invention consists in a porcine intra-vaginal device of a shape and size adapted to be positionable in the vaginal tract across the hymenal ring of a target animal (eg; a gilt) to extend to both sides of the hymenal ring of the animal, the device having or being (at least in part) a progesterone impregnated matrix or matrices to be on at least either side of the hymenal ring, the device having variable geometry means which deploy in the vestibule upon insertion to retain the device in the vaginal tract.
Preferably said matrix or matrices are at least 150 cm
2
in total area.
Preferably said total area of progesterone impregnated matrix or matrices is greater than 172 cm
2
.
Preferably said matrix or matrices carry a progesterone load of at least 1.9 g.
Preferably said progesterone load is from 1.9 to 2.5 g.
Preferably, for gilts, said progesterone load is about 2.2 g.
Preferably said progesterone load is at least substantially all carried by the matrix or matrices within 1.2 mm of its release surface.
Preferably the device has a nylon (or equivalent) spine with an impregnated matrix formed thereabout.
Preferably the matrix is a progesterone containing silicone rubber material which has been formed by injection of the uncured progesterone containing matrix as a liquid into a mould for a sufficient time to achieve a mould temperature or temperatures within the range of from 100° C. to 210° C. and a shape retaining at least partial cure thereof.
In another aspect the present invention consists in an intra-vaginal device having an elongate body (preferably not articulated) to be inserted in a pig with part on either side of the hymenal ring of a pig and having variable geometry retention means dependent from that part of the elongate body to be located in the vestibule of the vaginal tract, said variable geometry retention means being capable of assuming a vestibule engagement form after release from an insertion mode.
Preferably said vestibule geometry retention means is or are capable of assuming a third mode, ie. a withdrawal mode upon the application of an external force to part of said device within said vestibule or to any means dependent therefrom extending towards and/or through the vulva.
Pref

Affiliated with

Also associated with

Rating

Intra-vaginal device for pigs does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Intra-vaginal device for pigs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Intra-vaginal device for pigs will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2890220