| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | May 12, 1987 |
| PATENT TITLE |
Process for formulating a synthetic drug for use in animal feed, and resulting formulation |
| PATENT ABSTRACT | A method of formulating a synthetic drug for use in animal feed, for the purpose of reducing carry-over of the synthetic drug to subsequent lots of animal feed in the feed mill |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | February 15, 1983 |
| PATENT REFERENCES CITED |
Reynolds, A. "A New Technique . . . Spherical Particles", Mfg. Chemist & Aerosol News, 41, 40-43 (1970). Conine et al., "Preparation of . . . Spheres.", Drug and Cosmetic Industry, 106, 38-41 (1970). |
| PATENT PARENT CASE TEXT | This data is not available for free |
| PATENT CLAIMS |
I claim: 1. A substantially-dustless minigranule comprising from about 1 to 40 percent on a dry weight basis of sulfamethazine, or a physiologically-acceptable salt thereof, from about 50 to about 98 percent on a dry weight basis of a physiologically-acceptable carrier and from about 1 to about 10 percent on a dry weight basis of hydrolyzed starch, said minigranule ranging in size of from 0.85 mm to 0.18 mm in diameter and being from about 1.0 to 2.5 times its cross-sectional dimension in length. 2. A substantially-dustless minigranule comprising from about 1 to 40 percent on a dry weight basis of nicarbazin, from about 50 to about 98 percent on a dry weight basis of a physiologically-acceptable carrier and from about 1 to about 10 percent on a dry weight basis of hydrolyzed starch, said minigranule ranging in size of from 0.85 mm to 0.18 mm in diameter and being from about 1.0 to 2.5 times its cross-sectional dimension in length |
| PATENT DESCRIPTION |
BACKGROUND OF THE INVENTION The present invention relates to a method of formulating a synthetic drug for use in animal feed, for the purpose of reducing carryover of the synthetic drug to subsequent lots of animal feed in the feed mill. A growing concern has developed in the animal feed industry concerning the carryover of drugs in medicated animal feeds. Sulfamethazine, as an example of such a synthetic drug, exhibits electrostatic properties which cause it to cling to feed mill equipment so that when the equipment is emptied, and a different lot of animal feed is added to the mill equipment for processing, undesired sulfamethazine residues appear in that subsequent lot of animal feed. This also creates the problem of producing a uniform formulation, as well, if the subsequent lot of medicated animal feed is intended to contain sulfamethazine. A recent study has shown increased sulfamethazine residues in pork liver and kidney due to this drug carryover problem. There is little prior art concerning the reduction of cross-contamination of feed mill equipment by medicated feeds. Chapman, in U.S. Pat. No. 4,211,781, teaches a process for preparing a substantially dustless animal feed premix by merely mixing the active ingredient with a non-toxic oil and an edible carrier. Ludwig, in U.S. Pat. No. 4,048,268, teaches substantially the same process used in the present invention. The purpose of that invention was, however, related to a method of stabilizing the microorganism produced antibiotic tylosin, which is susceptible to deterioration causing a considerable loss of potency, but having no carryover problem. The apparatus typically used in the process of the present invention is disclosed in U.S. Pat. No. RE27214, or U.S. Pat. No. 3,579,719. These patents teach the use of that apparatus for making spherical granules. This invention greatly reduces the carryover of a synthetic drug in animal feed mill operations. SUMMARY OF THE INVENTION The purpose of this invention is to provide a method of formulating a synthetic drug for use in feed which will reduce the carryover of the drug from one lot of feed to a subsequent lot in feed mill operations. The process involves intimately mixing the drug with a carrier, a physiologically-acceptable binder, and water, extruding the mixture through a perforated plate having relatively small aperatures into elongated strands of extrudate, and contacting the elongated strands of extrudate with a moving frictional plate, imparting motion to said extrudate and developing a tumbling, rolling bed thereof wherein the strands are reduced to nearly spherical particles, called minigranules, drying them to remove excess moisture, and sieving the minigranules through meshed wire screens to insure proper particle size. DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for minimizing the carryover of a synthetic drug in animal feed mill equipment. The steps of the process include (A) intimately admixing the synthetic drug with (1) a physiologically-acceptable carrier and (2) water; (B) blending the intimate admixture of (A) with (3) a physiologically-acceptable binder;(C) extruding the thus blended admixture under pressure through a perforated plate forming an extrudate of elongated strands having a length generally exceeding the cross-sectional dimension; (D) reducing the strands of extrudate into nearly spherical particles; (E) removing the excess water from the particles (D); and (F) sieving to form uniform particles termed "minigranules". The term "synthetic drug" has a specific definition in connection with this application. "Synthetic" refers to the method of preparation of the compound, meaning the drug was completely prepared using chemical compounds, and no part of the drug was fermentation derived. "Drug" refers to an animal medicament, a substance for veterinary use in animals such as a growth promotant, coccidiostat, antimicrobial, antibacterial, anthelmintic, or antihistomonad. The term "feed premix", as used in the present application, is defined as the synthetic drug, in the form of the minigranule alone or, more typically, diluted with a suitable edible diluent. Either type of premix is intended to be further diluted with the animal ration, and the final feed mixture obtained then may be formed into pellets, if desired. The carrier used in the first step of the present process can be any physiologically-acceptable carrier. Suitable physiologically-acceptable carriers include finely-divided materials derived from cereal grains; oil seeds and their by-products; forages, silages, and their by-products; by-products of the lumber, sugar, fruit juice, and vegetable juice industries; clays such as diatomaceous earth; and vermiculite. Because of their widespread availability, solvent-extracted soybean feed, soybean mill run, corn flour, milo flour, wheat middlings, or alfalfa meal are preferred. Especially preferred carriers for use in this novel process include solvent-extracted soybean feed, corn flour, and alfalfa meal, with the carrier of choice being solvent-extracted soybean feed. The carrier may be used in from about 50 to about 98 percent on a dry weight basis to form the admixture. Physiologically-acceptable binders found useful in preparing the admixture include starch, gelatin, polyvinylpyrrolidone, soy protein, cellulose, bentonite, acacia powder and lignin sulfonate. Of these, starch is the binder of choice. However, as noted below in Example 5, it is not alays necessary to add a separate binder since another component may additionally serve as a binder. The binder may be present in from about 1 to about 10 percent by weight of the admixture on a dry weight basis, preferably from about 3 to about 5 percent by weight on a dry weight basis. The exact percentage of the synthetic drug in minigranules prepared according to the present invention will vary somewhat with the identity of carrier and other factors. Generally, the minigranules will contain from about 1 to about 40 percent of the synthetic drug on a dry weight basis. Where the carrier is solvent-extracted soybean feed or alfalfa meal, the full range of 1 to 40 percent is possible. However, with certain other carriers, less than 40 percent of the synthetic drug is possible. For example, those minigranules prepared using a carrier selected from the group consisting of corn flour, milo flour, soybean mill run, and wheat middlings, can contain from about 1 to about 25 percent of the synthetic drug on a dry weight basis. These differences in percent weight content of the drug are due in part to the variation in ability of the carriers to absorb moisture and to thereby form a suitable admixture for processing through the extruder and thence to the forming of the minigranules from the strands of extrudate. The percent of synthetic drug, physiologically-acceptable carrier, and binder is calculated on a dry weight basis and is considered without reference to the water or other components present. Thus, these three components together constitute 100 percent of the composition for purposes of calculating individual percentages. The process of the present invention used to control the carryover of a synthetic drug is described in detail below. In step (A) of the process, the synthetic drug, or a suitable physiologically-acceptable salt thereof, a suitable carrier, and some water, are blended together in a blender. Suitable type blenders include a ribbon blender, tumbling cone, twin shell blender, vertical mixer, paddle mixer, sigma arm mixer, pony mixer, or the like. Preferably, the mixing is done in a ribbon blender. Although unnecessary in production type equipment, it may be desirable in pilot plant equipment to empty the ribbon blender into a suitable container, and the sides, bottom and blades of the ribbon blender be scraped clean. All of the material is then returned to the blender for additional mixing. Thus, step (A) of the novel process is carried out by intimately blending a mixture comprising from about 1 to about 40 percent by weight on a dry weight basis of the synthetic drug, about 50 to about 98 percent by weight on a dry weight basis of a carrier selected from the group described above, and water, to form an intimate admixture. When step (A) is finished, that is, when the blending is adjudged to be complete, step (B) of the process is carried out. The binder, along with some water, is added to the admixture in the blender and mixing continued for as long a time as necessary to provide intimate mixing of the various components with one another. The amount of binder required is calculated on a dry weight basis and equals from about 1 to about 10 percent by weight, preferably from about 3 to about 5 percent by weight of the components of the product of step (A). It has been found that reasonably prolonged mixing does not adversely affect the properties of the material being blended for processing in the extruder, the next step in the process. At the conclusion of this mixing, the mixture appears as a moist but free-flowing particulate material which forms a dough when compressed. This moist but free-flowing particulate material may have an overall moisture content of from about 43 to about 50 percent by weight, most typically and preferably about 47 percent by weight. The admixture prepared as described above is next introduced into an extruder. Extruders are well known to the art. Generally, the material to be extruded is fed into a hopper over one end of a rotating screw auger disposed in a cylinder. The screw auger transports the material to be extruded the length of the cylinder and discharges said material into an annular space defined on one or more sides by a perforated plate. The material is forced through the perforations of the plate by the pressure created by transporting more of said material into said annular space than can be confined therein. The faster the material accumulates in the annular space, the greater the pressure being exerted to force said material through the perforations in said plate. The screen or perforated plate through which the admixture is extruded suitably contains round perforations of from about 0.5 mm. to about 1.5 mm. in diameter. The perforation diameter of choice in the plate is 0.8 mm. This diameter size of extrudate results in a range of particle sizes which is most useful for uniform distribution in animal feeds. The elongated strands of extrudate produced by the extruder will vary in length from something a little more than the cross sectional dimension to a measurement many times the breadth of said strand. The length of strands will vary with the relation of the perforated plate to the vertical. A plate set on the vertical will form strands having a shorter length than those coming from a plate facing down. Furthermore, the cross sectional dimension of the perforations also influences the length of the strands. In any event, the strands of extrudate do not tend to stick together under normal handling and can be spread on trays for drying or added directly to a particle-forming apparatus without encountering aggregation, agglomeration, coalescence, or disintegration. While it is possible to remove the excess moisture from the strands of extrudate prior to forming the minigranules, it is preferred in the present process that such particles must be formed before the excess moisture is removed. The extrudate strands are therefore divided into particles, the length of which particles varies from about 1.0 to about 2.5 times their cross-sectional dimension. The division of the extrudate strands into short lengths is accomplished by contacting the strands with a moving frictional plate, said plate being of either a flat or curved form and having either a smooth or serrated surface, preferably the latter, said frictional plate moving at a velocity sufficient to overcome the inertia of said extrudate. The moving frictional plate sets up a rolling, tumbling bed of extrudate and in such bed, the elongated strands are divided into particles of from about 1.0 to about 2.5 times their cross-sectional dimension in length. Illustrative of devices wherein this operation can be performed are: (a) coating pans used in pharmaceutical and confectionary industries and well known in the art, which pans can be operated satisfactorily whether set in a vertical plane or tilted at an angle; (b) granulating pans, also well known in the art, such as those used in pelletizing "taconite" iron ore for shipment and characterized by being of large diameter and with a relatively low integral circumferential side wall confining the particles on the flat surface (these pans are generally operated at a slight angle, perhaps 15.degree. off the horizontal and are rotated slowly); (c) an apparatus for dividing moist plastic extrusions into short lengths, comprising a stationary vertical cylindrical container having a rotatable flat or outwardly curved circular frictional plate disposed therein, said plate being disposed on a shaft at approximately a right angle thereto, such device being the subject of U.S. Pat. No. RE27214, or U.S. Pat. No. 3,579,719. Preferably, the extrudate reduction is accomplished using the device of (c) above by: (1) contacting said extrudate with a circular frictional plate mounted horizontally in a vertically disposed stationary cylindrical vessel; (2) rotating said plate at a speed sufficient to overcome the inertia of said extrudate; (3) imparting velocity to said extrudate such that said extrudate moves in a curved path toward the periphery of said plate; (4) establishing a moving doughnut-shaped ring of said extrudate; and (5) continuing such movement until said extrudate is reduced to particles of from about 1.0 to 2.5 times their cross-sectional dimension in length. The circular frictional plate is suitably operated at speeds ranging from 1200 to about 1800 rpm. The minigranules produced in the previous step are dried until they contain from about 5 to about 12 percent, preferably about 10 percent residual moisture. The drying operation can be suitably accomplished by spreading said particles on trays and air drying at room temperature; by kiln drying at temperatures up to about 70.degree. C.; or by loading said particles into a fluidized-bed dryer and blowing warm (approximately 70.degree. C.) dry air through the fluidized bed of said particles, this latter being the method preferred. The final step in this carryover control method is the necessity to pass the dried minigranules over meshed wire screens to remove granules greater than 20 mesh and less than 80 mesh. The acceptable particles collected will range in size from 0.85 mm to 0.18 mm in diameter. The dust-free minigranules containing the synthetic drug now possess the proper characteristics to greatly reduce the problem of carrying over the drug to subsequent feed lots. A number of commercially available synthetic drugs may be used in the process taught by this invention to reduce carryover of those drugs in feed mills. Representative examples include, but are not limited to: acetyl sulfamethoxypyridazine N.sup.1 -acetylsulfanilamide acetyl sulfisoxazole amprolium arprinocid arsanilic acid buquinolate carbadox carbarsone clopidol coumaphos decoquinate dibutyltin dilaurate dichlorvos dimetridazole dinitolmide ethopabate furaltadone furazolidone halofuginone ipronidazole levamisole hydrochloride melengestrol acetate nicarbazin nifuraldezone nitarsone nitrofurantoin nitrofurazone nitromide phenothiazine phthalylsulfathiazole piperazine pyrantel robenidine hydrochloride ronidazole roxarsone sodium arsanilate succinylsulfathiazole sulfabenz sulfabenzamide sulfabromomethazine sulfachloropyrazine sulfachloropyridazine sulfadiazine sulfadiazine sodium sulfadimethoxine sulfaethidole sulfaethoxypyridazine sulfaguanidine sulfamerazine sulfamerazine sodium sulfamethazine sulfamethizole sulfamethoxypyridazine sulfamoxole sulfanilamidomethanesulfonic acid triethanolamine salt sulfanilic acid sulfanitran sulfaphenazole sulfapyrazine sulfapyridine sulfaquinoxaline sulfarsphenamine sulfathiazole sulfathiazole sodium sulfazamet sulfisomidine sulfisoxazole thiabendazole and the like. The process of the present invention may be used not only for a synthetic drug alone, and its physiologically-acceptable salts, but also for synthetic drugs in combination with fermentation derived antibiotics |
| PATENT EXAMPLES | available on request |
| PATENT PHOTOCOPY | available on request |
|
Want more information ? Interested in the hidden information ? Click here and do your request. |