Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
2001-07-16
2003-03-18
Jones, Dwayne C. (Department: 1614)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
Reexamination Certificate
active
06534526
ABSTRACT:
BACKGROUND OF THE INVENTION
Laminitis is a potentially devastating condition which can strike any hoofed animal, but is primarily known to affect equine. Generally speaking, laminitis is a syndrome involving the sensitive laminae of the hoof. The lamina is a layer of loose connective tissue attaching the distal phalanx to the hoof wall.
The syndrome can proceed through several stages, beginning with little or no visible signs of the disease, though lamellar damage may have already occurred at this point. Once begun, if unchecked, the condition can advance to a chronic stage, which can involve detachment of the lamina from the hoof and palmar rotation or even distal displacement of the bone. At the chronic stage, a horse can be left with continuous mild or severe pain which can last indefinitely. It is generally held that the laminitis syndrome is responsible for the permanent debilitation of countless horses every year, affecting all breeds around the world.
While the pathophysiology of the syndrome has gained understanding in recent years, attempts at treatment and prevention of the disease have met with limited success. In the past, treatment was limited to physical treatment of the affected foot, by, for example, minimizing movement by standing the horse in a deep (18 inch) bed of shavings, or fitting special frog supports for the animal. Chemical treatment of symptoms has also been utilized in the past, such as administration of phenylbutazone for inflammation and pain.
More recently, studies have shown that laminitis may begin as a primary vascular disease, and treatment methods have focused on vascular control mechanisms. For example, it has been proposed that digital venoconstriction may be the primary disturbance occurring in the initial stages of laminitis. As a result, certain substances have been examined that may interrupt this process. For example, certain catecholamine antagonists have been examined for possible efficacy. Catecholamines are believed to be mediators in the hormone cascade which can lead to vascular constriction. Specifically, certain &agr;-adrenergic antagonists have been examined as possible agents for inhibiting suspected hormone cascades which can lead to the vasoconstriction found in early laminitis. Success has been limited, however. For example, the &agr;-adrenergic antagonist phenoxybenzamine has been associated with side effects such as hypotension, recumbency, and a prolonged duration of action. Similarly, when the &agr;-adrenergic antagonist acepromazine maleate has been examined, undesirable side effects such as sedation and cholinesterase inhibition can occur in the animal.
In spite of the recent advances in understanding the development of laminitis, specific hormone cascades and possible mediators to the vasoconstriction remain unsubstantiated. Successful treatment of the syndrome remains frustratingly infrequent and uncertain. The present invention is related to a method for treating laminitis and preventing the damage which has been known to occur in the chronic stages of the disease.
SUMMARY
In general, the present invention is directed to a method for treating laminitis in animals. More specifically, the present invention is directed to a method for treating the symptoms associated with the laminitis syndrome.
When laminitis proceeds to a chronic stage, laminar detachment can occur, which in turn can lead to palmar rotation and/or vertical displacement of the distal phalanx. The method of the present invention, properly administered, can prevent this laminar detachment.
Laminitis is believed to be due to microcirculatory system impairment. The method of treatment of the present invention includes administering to an animal suffering laminitic symptoms a composition which includes an &agr;-adrenergic antagonist. The &agr;-adrenergic antagonist chosen for treatment is preferably one which does not cross the blood-brain barrier, thus allowing treatment without neuroleptic side effects. In one particular embodiment, the &agr;-adrenergic antagonist can be domperidone.
The &agr;-adrenergic antagonist used for treatment of the animal can be administered to the animal by any suitable method. For example, the &agr;-adrenergic antagonist can be administered to the animal orally, subcutaneoously, or intramuscularly. Generally, the &agr;-adrenergic antagonist will be administered to the animal in an amount from about 0.2 mg to about 3.3 mg per kg weight of the animal. When the treatment is administered to the animal subcutaneously or intramuscularly, the dosage can be, for example, from about 0.08 mg to about 1.32 mg per kg weight of the animal. Administration of treatment can occur at least once per day up to about six times per day (every four hours).
Lamellar damage due to laminitis is known to occur primarily in horses, but it can occur in any hoofed animal. The treatment of the present invention is therefore equally efficacious for other hoofed animals, such as, for example, cattle, camels, goats, pigs, and sheep.
Other objects, features and aspects of the present invention are discussed in greater detail below.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention, which broader aspects are embodied in the exemplary construction.
The present invention is generally directed to treatment of laminitis in hoofed animals. More particularly, the present invention is directed to various processes and methods for treating laminitis and prevention of lamellar damage due to laminitis in animals. The process of the present invention can be used either as a prophylactic for laminitis in hoofed animals or alternatively as a treatment for laminitis after physical manifestations of the disease have appeared. In fact, experimental trials of the treatment have led to long term elimination of any signs of the disease as well as speculation of no return of symptoms in the future.
In general, the objects and advantages of the present invention are achieved by administering to a laminitic animal a composition containing an &agr;-adrenergic antagonist. Preferably, an &agr;-adrenergic antagonist should be chosen that does not substantially cross the blood-brain barrier in order to minimize the possibility of the animal suffering adverse behavioral or neurological side effects. For instance, in a preferred embodiment, the &agr;-adrenergic antagonist is domperidone.
Domperidone is the common name for the compound 5-Chloro-1-[1-[3-(2,3-dihydro-2-oxo-1H-benzimidazol-1-yl)propyl]-4-piperidinyl]-1,3-dihydro-2H-benzimidazol-2-one. Domperidone is registered under the Chemical Abstact Service registration system and has been assigned registry number 57808-66-9. Domperidone is chemically unrelated to other &agr;-adrenergic antagonists, such as phenoxybenzamine and acepromazine maleate. Unlike other &agr;-adrenergic antagonists, domperidone does not cross the blood brain barrier. Therefore, central neurological side effects are not a concern when using domperidone as a treatment for laminitis.
Although a great deal of the pathophysiology of laminitis remains unknown, current research suggests it to be a microcirculatory problem. Current research suggests that prior to lamellar damage, an as yet unknown hormone cascade causes blood vessels to constrict in the distal digit of the animal. It is believed that this constriction involves both pre-capillary bed vessels (arterioles) as well as post-capillary bed vessels (venules). In any case, it is generally held that flow of blood to and/or from the laminar capillaries is impeded in the earliest stages of the disease.
Vasoconstriction which impedes the blood flow in the hoof can cause edema in the surrounding tissues. This in turn can lead to an increase in interstitial pressure which can further impede circulation. The net effect, if left unchecked, can lead to ischemia of the surrounding tissues (inclu
Clemson University
Delacroix-Muirheid C.
Dority & Manning
Jones Dwayne C.
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