Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Implant or insert
Reexamination Certificate
2000-10-17
2004-08-03
Page, Thurman K. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Implant or insert
C424S438000
Reexamination Certificate
active
06770288
ABSTRACT:
TECHNICAL FIELD
This invention relates to a substance delivery system.
Reference throughout the specification shall be made to the use of the present invention as a drug delivery system for use in animal body cavities, such as the vagina.
It should be appreciated however that the present invention can be used to deliver substances other than drugs and can be used in relation to humans and in other body cavities, for example the rumen, ears and so forth.
BACKGROUND ART
Drug delivery systems are used extensively in controlled breeding and reproductive management. Although considerable research has been invested in the design of these devices, there are still problems associated with them.
Firstly, these devices are required to be retained within the body cavity for the slow release of drugs over a period of time. To facilitate this, various arms and projections have been built into the device which can either engage with the walls of the body cavity, or make the device wide enough such that when in the body cavity it cannot naturally exit the animal through the entrance orifice.
Major problems with the provision of such arms or projections is that they can irritate or even rupture the lining of the body cavity, causing distress to the animal and providing a site for possible infection.
A major problem with drug delivery devices is that traditionally they have been manufactured with the drug impregnated into the material from which the device is made. Typically, this material is in many instances a matrix of silicone.
To manufacture devices from drug impregnated silicone is expensive.
A further disadvantage of using a drug impregnated device is that it is very difficult to dispose. For example, the hormones used in reproductive management are required to be disposed in accordance with heavily regulated environmental procedures. As it is always possible that the drug within the silicone matrix had not been fully delivered to the animal when the device is removed, the whole device will have to be disposed as the whole device is the drug delivery system.
It would be desirable if the devices could be reused.
Another problem with the devices is that they have a specific dose rate which cannot be readily changed. Further with these devices, the treatment cannot be changed or customised according to requirements.
In some animals such as cows, the progesterone dose rate for synchronising oestrus is critical to the reproductive cycle. Typically, in the pre-luteal phase the animal will reproduce follicles which are the stage that ovum are produced. Follicule maturation then occurs and the follicule develops into the corpus luteum in the ovary. Fertilisation can then occur.
Therefore healthy follicules are a pre-requisite for conception.
Exogenous progesterone is often delivered to cows to inhibit follicle maturation as a means of synchronising oestrus. When the treatment is removed progesterone levels fall and the animals cycle in a controlled manner. If however the progesterone blood levels during treatment fall below critical levels oestrus synchronisation may still occur but follicle integrity may be compromised thereby reducing conception rates and fertility. This condition highlights the necessity to maintain adequate progesterone dose using an efficient drug delivery system.
To maintain adequate dose previous drug delivery systems have contained excessively high progresterone dose levels. This has resulted in high residual levels of drug remaining in the device after use which has adverse economic and environmental impacts.
In addition, various applications of a treatment may require different drug delivery periods. For instance, one treatment may require six days drug delivery, another treatment may require ten days drug delivery. In this situation an ability to offer dose choice would be feasible. Also, very large animals of the European breeds may require larger doses than the smaller animals on pastoral systems in countries like New Zealand.
What would be desirable then is a drug delivery device that delivers the drug in a sufficient quantity over the treatment period with a minimum of residual drug remaining in the device matrix after treatment to achieve production economies and to avoid adverse environmental impacts caused by disposing used devices in land fills that contain large quantities of hormones. Flexibility in being able to change or customise the treatment would be desirable.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.
DISCLOSURE OF INVENTION
According to one aspect of the present invention there is provided a substance delivery device,
including a substance dispenser
characterised in that the surface area of the substance dispenser is independent of the supporting structure of the substance delivery device.
The substance delivery device should now be referred to as a drug delivery device such as an intravaginal release device (IRD).
It should be appreciated however that a device in accordance with the present invention can be adapted for use in other body cavities such as the rumen, the auditory system, the gum area and other body cavities.
It should also be appreciated that the present invention can be used in both humans and animals.
In preferred embodiments, the present invention may be used in the treatment of cows.
The applicant has recognised that a dissolution process as a means of drug delivery is very effective provided the drug release process is controlled. The applicant has in his invention concentrated on the principles which aid dissolution, namely the surface area and thinness of the substance dispensers, surface area exposed directly to the body cavity and in some embodiments the holding of drugs in cavities in the dispenser.
It should be appreciated however that other drug delivery methods can be used such as mechanical or electronic.
The present invention can also be used to introduce a biological monitor such as a thermometer.
As a further issue the applicant has also been conscious of providing a ready means by which the drug profile delivered by the substance delivery device can be readily modified. For example, different animal weights require different amounts of drugs.
The substance being delivered may come in a variety of forms. For example, these may be liquid, bullets, powder, gel, and other such forms. However, this list should not be seen to be exhaustive.
In one embodiment, the substance dispenser may be a pod with a housing containing vanes. Preferably, the pod may take the form of an obloid. The vanes may be positioned so that they are axially directed through the centre of the sphere and are in contact with the inside of the sphere at their outer edges.
Having one embodiment of the substance dispenser as a pod should not be seen to be limiting, as the principles of the present invention may be applied using a substance dispenser of a different configuration.
For example the substance dispenser may be a substantially cylindrical device containing vanes, or containing a grid, honeycomb or mesh arrangement. The grid, honeycomb or mesh arrangement may also be applied to the pod configuration for equal effectiveness.
In preferred embodiments, the dispenser may be a temporary attachment to a supporting structure, or could be applied as a permanent attachment to a supporting structure. In a further preferred one embodiment the dispenser may be a free-standing delivery pod within the body cavity.
Preferably the dispenser may be used as a temporary attachment to a supporting structure, such as can be found in New Zealand Patent Application No. 328967. Reference to the device in New Zealand Patent No. 328967 should not be seen to be limiting, as the supporting structure may constitute another form of device while still maintaining the advantages of the dispenser.
In some embodiments in the present invention the dis
Finnegan Henderson Farabow Garrett & Dunner LLP
George Konata M.
Page Thurman K.
Pfizer Products Inc.
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