Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Specially adapted for ruminant animal
Patent
1996-10-07
2000-02-29
Page, Thurman K.
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Specially adapted for ruminant animal
424439, 424442, A23K 118
Patent
active
060306378
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to pellets or boli for administration to ruminant animals and in particular to cattle and sheep. The invention particularly concerns boli intended to reside in the rumeno-reticular sac and to release predetermined quantities of one or more biologically active substances over an extended period of time.
The delivery of active agents to ruminant animals by administration of pellets or boli is a well established procedure having been practised for over thirty years. The-boli are typically introduced into the rumeno-reticular sac via the mouth using a balling gun and remain there for a period of time which may extend to several months.
There are in general two types of boli in use. They are characterised according to (i) whether the active agent is released continuously with time, or (ii) is delivered as a series of pulses, separated by discrete periods of time during which the animal receives no active agent. Anthelmintics for the control of parasites are commonly administered by both types of bolus.
EP-A-0243111 and EP-A-0164927, for example, describe the construction of continuous release and pulse release boli respectively and boli described in these publications are commercially exploited. These patent applications disclose boli of generally elongate, cylindrical shape where the rate of drug release or the timing of that release is controlled by the rate of axial corrosion in the rumen juices of a magnesium alloy rod or tube. The rod/tube is disposed longitudinally in the bolus and coupled electrically to a cathodic element.
In the case of commercially available boli according to EP 0243111, the active agent is present in the bolus as an ingredient of weighted cathodic tablets contained within a magnesium alloy tube. The rate of corrosion of this tube determines the rate of erosion of the contained tablets, the active agent content of which is released continuously. In the example boli constructed in accord with EP 0164927, the drug is contained in the bolus as a plurality of discrete interlocking tablets disposed over an axial magnesium alloy rod and which carries an iron cathode at one end, the latter also serving as a weight. The animal's rumen juices degrade the alloy rod axially, over a period of time, to-successively release the tablets.
In both cases the amount of benzimidazole required for a cattle bolus with a life of 120 days would be approximately 5-12 grams depending on the tyre of benzimidazole and the size of animal. This occupies a considerable volume and results in a bolus length which may extend to 9 cm. These boli deliver the active agent sequentially, the last doses of drug being released after the corrosion of some 5-9 cm length of magnesium alloy rod or tube.
Both types of release mechanism have their advantages. Pulse release may be preferred to continuous release on the grounds that it can result in the more economical use of an expensive active agent and may also prove less prone to conferring drug resistance to the parasites it is being employed against. However, it is generally more difficult to design and construct effective pulse release boli than is the case with continuous release. There is a need for a more simple and economical pulse release system than has hitherto been employed.
The present invention relates to a pulse release system which is simple and economical to construct and is particularly suited to the delivery of highly active agents such as avermectins where the quantity of anthelmintic required to control parasites is much smaller than is the case with benzimidazole or levamisole. However, the principles used may be applied to the pulse release of other active agents including growth promoters, trace elements, vitamins etc which are commonly administered to ruminant animals. Example active agents applicable to the present invention are disclosed in the aforementioned patent applications.
Thus, the present invention concerns a novel method of delivering active agents to a ruminant animal as a series of pulses by using several indivi
REFERENCES:
patent: 4066754 (1978-01-01), Chou
patent: 4578263 (1986-03-01), Whitehead
patent: 4863455 (1989-09-01), Whitehead
Benston, Jr. William E.
Page Thurman K.
LandOfFree
Pellet for administration to ruminants does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pellet for administration to ruminants, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pellet for administration to ruminants will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-680347