CA1104497A - Rumen-stable pellets - Google Patents

Abstract

Abstract of the Disclosure Pellets adapted to be orally administered to ruminants are disclosed. The pellets have a core comprising a nutrient and/or medicament, and a coating which protects the core in the environment of the rumen is also provided to allow utilization of the core in the abomasum and/or intestine. The coating comprises a polymeric matrix which is resistant to the mildly acidic environment of the rumen, and a hydrophobic substance and a flake material dispersed throughout the continuous matrix. The core may contain a neutralizer if desired.
The continuity of the polymeric matrix is destroyed in the more acidic environment of the abomasum.

Description

Thls invention relates in g~neral to pellets adaptet to be orally admini~tered to ru~inants and which are beneficial to ruminants after passing the rumen and reaching the abomasum and/or intestines.
More partlcularly, this invention relates to pellets having, ln terms of structure, a core maeerial such as a nutrient or medlcament, ant an imperforate coating over the core material which protects the core in the environment of the rumen, but which loses continuity under the more acid$c conditions of the abomasum to render the core material available for utilization by the animal.
In ruminants, ingested feed first passes into the rumen, where it is pre-digested or degraded by fermentation. During this period of fermentation the ingested feed may be regurgieated to the mouth via the reticulum where it is salivated and ruminated. After a period of fermen-tation regulated by natural processes and variable depending on the animal and the feedstuff, adsorption of digested nutrients starts and continues in the subsequent sections of the digestive tract by the ruminant anlmal.
This process is described in detail by D. C. Church, "Digestive Physiology and ~utrition of Ruminant3", Vol. 1, O.S.U. Book Stores, Inc., of Corvallis, Oregon.
The rumen, the largest of the four stomach compartments of ruminants, serves as an important location for metabolic brea~dGwn of ingested foodstuffs through the action of microorganisms ~hich are present therein. Ingested foot i9 typically retained in ehe rumen for from about 6 to 30 hours or longer in some instances, during ~hich time it is sub~ect to metabolic breakdow~ by the rumen microorganisms. ~uch ;i ingested protein ~aterlal is broken d~wn in the rumen to soluble peptites and amino acids and utilized by the rumen microorganisms. I~hen the rumen conten~s pass into the ab asum and intestine, the microbial mass is digested, thus providing protein to ehe ru~inant. Thus, the natural nutritional balance of the ruminant a.~imal is primarily a function of the microbial composition and population.
In preparing nutrients and medicaments intended for administraeion

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11~4~g7 to ruminants, lt 1s ~mportant to protect the ~ctive ingredionts against the environmental condltions of the rumen, i.e., microbial degradation and the effects of a pH of about 5.5, so the active substance will be saved until lt reaches the particular location where adsorption takes place. It is well known that the rate of meat, wool and¦or milk pro-duction can be increased if sources of growth limiting essential amino acits, and/or medicaments, are protected from alteration by microorganis~s residing in the rumen and become available for direct absorption by the animal later 1Q the gastrointestinal tract.
Materials which protect the core against degradation by the rumen contents should be resistant to attack by the rumen fluid which contains enzymes or microorganisms but must make the active ingredient available rapidly iQ the more acidic fluid of the abomasum at a p~
within the normal physiological range of about 2 to about 3.5. To more easily coat or encapsulate active ingretients in protective materials, the protective materials should be soluble in certain organic solvents for coating purposes.
Because proteins are subject to breakdown in the rumen, it has been suggested that protein-contaiQing nutrients fed to ruminants be treated so as to permit passage without microbial breakdown through the rumen to the abomasum. Suggested procedures have included coating the proteic material, for example, with fats and vegetable oils; heat treating of the protein material; reactirg the protein material with various compounds such as formaldehyde, acetylenic esters, poly~erized unsaturated carboxylic acid or anhydrites and phosphonitrilic halides, etc.
It is well known that all proteins found in animal and plant life are chemical compounds containing different combination~ of over 20 am~no acids, the number and arran8ement of such acids being fixed in any par~icular protein. Twelve of these amino acids can be synthesized in 30 nutritionally adequate amounts from other substances by biochemical processes normally present in most animals, but the remai~ing lO essential amino acids are not synthesized iQ surficient quantities and must be 11~44~7 ingested by the animal. Since the proportions of the constituent amino acids in a particular protein cannot be varlet, the essential amino acid least in ~upply limit~ the amount of that protein which can be produced by the animal. Consequently, for any given diet, there will be a parti-cular essential amino acid which limits the production of protein incor-porating that essential amino acid unless, of course, two or more such amino acids are equally limiting.
The appreciation of ehe above principles leads to the formula-tion of diets for nonruminant animals which provide the optimum proportion of amino acids and have enabled significant increases in protein produc~ion to be achieved. In the ruminant, dietary proteins and amino acids are, to a variable extent, broken down eo ammonia and various organic compounds by microbial fermentation in the first t~o compartments of the stomach (the rumen and reticulum). The bacteria and protozoa in these organs utllize these metabolites for their own growth and multiplication and the microbial protein so formed passes on to the abomasum, the compart-ment of the stomach corresponding to the stomach of nonruminants, where it is partially digestet. The process i8 completed in the small intestine and the amino acids are absorbed.
It is likewise ~ell-known that medicaments are more zffective when they are protected from the environment of the rumen. See, for example, U.S. Patent ~09. 3,041,243 and 3,697,640.
In accordance with the present inveneion, a polymeric coating having a hydrophobic substance ant a flake material dispersed therein, which is resistant to envlronmental conditions of the rumen but releases the core material under the environmental contitions of the abomasu~, provide~ a very desirable utilization efficiency by ru~inants. The core material may also contain a neutralizer to provide a pH above about 5.5.
The coating material has the ability to withstand euvironmental condltions of the rumen, and the ability to expose the core material of the pellet in the environment of the abomasum. Thus, the coating material is resistant to p~ conditions of abcut 5.5 for at least about 24 hours.

The coating material releases the core material upon exposure to abomasum environmental conditions having a pH of about 3.5 after a time of about 10 minutes to about 6 hours. The exposure of the core may occur by the coating becoming permeable to the fluids therein or by dissolving or disintegrating. Another requirement for the coating material is to have the ability to withstand storage conditions of relatively high heat and/or humidity with-out a significant amount of blocking.
Core materials having an adjusted pH of greater than about 5.5 and a water solubility of about 10 to about 70 grams per hundred grams water at 25C. are most useful in this invention.
Thus, any core material which is beneficial to the reminant such as a nutrient or medicament having characteristics within these para-meters may be used. Preferred core materials include amino acids, proteins, various other nutrients, as well as antibiotics and other medicarnents.
Thus, in accordance with the present teachings, there is provided a pellet which is adapted for oral administration to a ruminant which comprises a core material beneficial to the ruminant postruminally, and a coating surrounding the core material, the coating being resistant to pH conditions of about 5.5 for at least six hours and adapted to release pellet core material after exposure to a pH of about 3.5 after a time of about 10 minutes to about six hours and comprises a) a film-forming polymeric material containing at least one basic amino grouping in which the nitrogen content is from 3 to 14% by weight of the total molecular weight of the polymeric material, the polymeric material comprises at s ~ -5-~J .

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least one polymer, copolymer or blend of polymers which selected from the group consisting of cellulose propionate morpholinobuty-rate, aromatic basic amino-containing polymers, dialkylamino ethyl acrylates and methacrylates in which the alkyl group contains from 1 to 6 carbon atoms, condensatiGn polyesters and polyamides, b) from about 2 to 50%, based on the weight of the polymeric material, or a hydrophobic material dispersed in the polymeric material and selected from the group consisting of waxes, resins, polymers, fatty acids having from 12 to 32 carbon atoms, aluminum salts of fatty acids having from 12 to 32 carbon atoms, and polyfunctional carboxylic acids which have a ratio of from 10 to 22 carbon atoms per carboxyl group and a molecular weight of from 400 to 1000, and c) from about 10 to 200~, based on the weight of the polymeric material, of a physiologically acceptable flake material dispersed in the polymeric material.

BACKGROUND
U.S. Patent No. 3,619,200 relates to chemically modifying pellets and/or using a surface coating therefor. Pro-teinaceous feed is protected from breakdown within the rumen by the modification of protein itself, by the application of a pro-tective coating to the feedstuff, or by combination of both.
Various polymers are disclosed in this patent including copolymers of vinylpyridine and styrene. Canadian patent No . 911, 649 dis-closes treatment of proteinaceous materials with substances which are capable of reacting with proteins to form a polymeric protein-aceous complex on the surface of the material or by treating the proteinaceous material with a polymer or copolymer of a basic , ..,~, ,' -5a-~?4~97 vinyl or acrylic monomer. This patent also discloses the use of copolymers and terpolymers derived from essentially a basic substituted acrylate or methacrylate monomer and at least one ethylenically unsaturated compound as rumen stable coatings.
U.S. Patent No. 3,880,990 and British Patent No. 1,346,739 relate to an orally administratable ruminant composition wherein a medicin-al substance is encapsulated or embedded in a normally solid, physiologically acceptable basic polymer. The compositions are produced -5b-,:, .

~Q4~7 by dispersing a medlci~al substance in a first solvent and adding thereto a second solvent which is mi~cible with the firqt ~olvent but in which the polymer and medicinal substance are substantially insoluble. There i9 no suggestion of modifying the polymer by the use of additlves. ~'.S.
Patent ~'o. 3,041,243 relates t5 coatings for oral medicament These coating3 ars water-lnsoluble but acid-soluble film-forming polymers. An example mentioned in this patent i9 2-methyl-5-vinyl pyridine copolymerlzed ~ith vinyl acetate acrylonitrlle, methyl acrylate or styrene.
U.S~ Patent No. 3,697,640 relates to materlals such as meticaments and nutrients for ruminants which are coated with nitrogen-containing cellulosic materials such as, for example, cellulose propionate morpholino butyrate. Thi3 patent, however, fails to suggest the use of any additives in the nitrogen-containing cellulosic materlal, and U.S. Patent No. 3,988,480 ~; relates to a proteinaceous feedstuff for ruminants which has been treated wlth acetic acid to render it rumen stable.
U.S. Patent ~o. 3,383,283 relates to coating pharmaceutical r~" pellet3 with a plurality of charges of fatty acid as a melt or in solution.
The ~atty acid may then be dusted with a fine inert powder such as talc.
There ls no suggestlon of using a continuous matriæ polymer.
,- 20 U.S. Patent No. 3,275,518 relates to a tablet coating composition ; comprising a film-forming resin or plastic and a hart water-soluble or water-dispersible 3ubstance. Stearic acid i9 mentloned as an optional water-insoluble wax which may be included as an additive. Additional materials such as dyes, pigments, ~ater-insoluble waxes, plasticizing agents, etc., may also be addet to the coating. however, the film-formi~g resin or olastic according to this patent is selected from the group consisting of poly(methylstyrene), methylstyrene-acrylonitrile copolymers, polytvinylchloride), poly(vinyl butyral), pentaerythritol or alkyd esters of rosin or modified rosin and terpene terived alkyd resins.
There is no suggestion of the polymers according to applicants' invention.
In fact, the plastic or resin i9 described as water-permeable, and the coating apparently i3 not designed for ruminant3.
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~ ~ ~?4 ~ ~7 ~ S. Patent No. 3,~23,9g7 relates to a methot of ~ealing polymeric material walls of minute capsules by treating the capsules ~ith a waxy material. The wax i9 introduced in a solvent whlch is subsequently dried and the wax is left as a resldue in the walls. The capsule walls shrink and lose solvent and then entrap the wax tightly as a sealing material. There i~ no indication, however, that the polymer coating is de~igned to function for ruminants, and the wax is used a~ a sealing material. Applicant's hydrophobic substance is dispersed in the polymer.
U.S. Patent No. 3,073,748 relates to tablets coated with a solution of an amphoteric film-forming polymer. The polymer is described as one selected from the group conslsting of copolymers of (a) vinyl-pyridines with (b) a lower aliphatic a,3-unsaturated monocarboxylic acld of 3 to 4 carbon atoms and copolymers of (a), (b) and a neutral co-monomer selectet from the group consisting of methyl acrylate, acrylonitrile, vinyl acetate, methyl methacrylate and styrene. There is no suggestion of using a disp2rsed additive.
British Patent ~o. 1,217,36; and Canadian counterpart ~o. 851,128 relate to a particulate feed additive composition for ruminants wherein each particle comprises one or more amino acids totally encased in a continuous film of protectlve material which is transportable through the rumen without substantial degradation therein but which releases the active substance posterior to the omasum when the particles have a density withi~ the range of 0.~ to 2.0 and diameters in the range of 200 to 2,000 microns. Suggested as ?rotective materials are fatty acid triglycerides such as hydrogenated vegetable and animal fats, waxes such as rice-brand wax, and resin wax blends which are emulsified and/or dissolved in the intestinal tract.
PELLETS
The pellets according to this invention are adapted for oral administration to a ruminant. The pellets are of a suitable size, such as between about 0.OS in. and 0.75 in. in diameter. Also, the pellets 9~

must be of 3uitable de~sity, i.e., a 3pecific gravlty of bet~een about 1 and 1.4, have acceptable odor, taste, feel, e~c. The pellet~ include a core ant a continuous, fil~ or coati~g completely enc2p~ulating the - core. The shape is usually not critical, except the pellets are commonly 3pherlcal for ea~e in coating.
CORE ~ATERIAL
The core is of a material beneficial to the ruminant upon pa3sing the rumen and reaching the abomasum antJor intestine. Normally, the core ic a solid material ~hich has been formed into particles, such as by pelletizing. The cores may then be rountet if tesiret, by con-ventional means, such as by tumbling. The core shoult have sufficient body or consistency to remain intact during handling, par~icularly during the coating operation. Suitable core materials include various medicaments and nutrlents such as, for example, antibioticc, relaxants, drugs, anti-para3ites, amino acids, proteins, sugars, carbohydrates, etc. The core may also contain inert filler material such as clay.
Some amino acids suitable for use as a core material, thelr p~
and solubility are as follows:
~mino Acids Solubilitv ant ~H of Saturated Solutions Solubility ~./100 g. water at 25C. pH
DL - Alanine 16.7 6.2 L - Asparagine 3.1 4.7 L - Arginine 21.6 11.8 L(-) - Cysteine 0.01 3-7 DL - ~ethionine 4.0 5.7 L(-) - Lencine 2.0 4.8 L(-) - Tyrosine 0.05 7.3 DL - Phenylalanine3.0 5.6 Other 3uitable active core materials include glucose, bacitracin, thyrotropin releasi~g factor and inoeitol. Proteins fram various sources are valuable for practice of the invention. Generally, proteins are polymers derived from various combinations of a~ino acids. Proteins are amphoteric substances which are soluble or suspentable in aqueous media either more acidic or more bas.ic than the particular protein being c~n~.ldered.
The core material may be made ready for coating by the following methot. The nutrient, medica~ent, or the like, and core neutralizer, if used, are mlxed with water, binders, a basic substance for ad~usting the core p~, and sometimes inert inorganic substa~ces added to atjust the specific gravity of the pellet and the resulting plastic dough-like mas~
i9 extrudet or rolled to obtain sultable size particles. Adhesive binders are added to strengthen the pellet and can be nontoxic vegetable gums, starches, cellulose derivatives, animal gums and other similar substances well-known in the art of food thickening and tablet making.
Inorganic additives uset to ad~ust the 3pecific gravity of the pellet inclute such substances as insoluble, nontoxic pigment-like materials such as metal sulfates, oxides and carbonates having a relatively high density. The final desirable range of specific gravity for the rumen protected pellets is fr~m 1.0 to 1.4. After creating suitable slze pellets by extruslon, rolling or other sultable means, the pellets are dried to remove the water. The pellets are then coated by contacting them with a solution of the protective coating material in a suieable ; 20 solVe~t or mixture of solvents a9 hereinafter describet. Typical solvents of value include lower alcohols, ketones, esters, hydrocarbons, and chlorinated hydrocarbons.
CORE NEUTRALIZATION
Core materials may be raised in pH to a predeter~ined degree by mixlng a basic neutralization substance therewith or by coating the core with a basic neutralization substance. The acidity is modified by adding nontoxlc, insoluble, baslc substances such as alkaline earth oxides, hytroxides, or carbonates, to the core materlal before the pellet forming step: Basic compounds of aluminum such as the various forms of hydrated alumina, alumi~um hydroxide, ant dibasic aluminum salts of organic acid3, hav~ng les~ than 6 carbon atoms, such as dibasic ; aluminum acetate may also be used. These basic substances are atded to _ g _ the pellets by mlxing the core material, ba-ic ~ubstance, and blnders as descrlbed abo~e before adding water. The amount u~ed depends on both the solubllity and rélative acidic nature o~ the proteinaeeous substance, on the coating composltlon used to obtain r~men protectlon ant on the thlc~ness of the coating applied. The amount of basic substance used i9 that quantlty which will theoretically neutralize or raise the p~ at least to 5.5, preferably to about 7.
The core material may be neutralized by the following method.
~o~toxlc, insoluble baslc substances such as oxides, hydro~ides, carbonates, and basic salts of magneslum, calcium, and aluminum are blended with finely-divided nutrient andlor therapeutic substances at the time these are prepared for pelletizing. The amount of basic substance used depends on several interacting factors related to the relative acidlty and/or solubiliey of the pellet, the time requiret for rumen proeection, and the time required for release in the abomasum. Normally, the weight of ba~ic substance will be within the range of 1-20Z of ehe total weight of the core. I~ atditlon to the nutrient or therapeutic substance and the basic substance, the pellets may contain binters, denslty modifl2rs, and other minor ingretients required for special properties, as is common practlce in the art of tablet making. In this practice of the i~vention, the various powdered ingredlents are-first dry blended to obtain a more or less homogeneous mixture, then water is atded to obtain a plastic dough-like mass. The tough ls then pelletlzet by extrusion, extrusion and tumbling, or by any method known to the art of pelletizing or tabletmaking. The water i9 re~oved by trying at ambient contl~io~s, in heated oven~ or fluidized beds. The dry pellets are then ready for subsequent coatlng operations performed by any method such as pan coatlng, fluitized bed coating, or spray coating or combination~ thereof.
Another method of core neutralizaelon ls based on the concept that, whereas the coating is permeable to water and acidic water borne molecules, not all of the pellet interior is required to be neutralized.
In this method of practicing the invention, the nontoxic inorga~io basic .

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substances are deposi~ed on the surface of ~he core ~aterlal prior to applicatlon of the coat~g. In practlce, the prefor~ed pellets are placed in a fluidizet bed or other coating apparatus and a di3perslon of an oxide, hydroxide, carbonate, or basic ~alt of magnesium, calcium, or aluminum in water or an organic liquid i~ sprayed on the pellet. The dispersion of basic substance preferably contains a binder and may also contain a protective colloidal substance where~n the ratio of binder plu3 protective colloidal subYtance to baslc substance is less than about 1:3. The amount of basic substance coated onto the pellet is normally from about 1 to about 20% of the ~eight of the core material.
The binder and protective colloidal substance can be the same substance or different and are preferably soluble or dlspersible in water and in the organic liquid used to suspend the basic ~ubstance. 8uch binder materials as relatively low molecular weight cellulose derivatives, synthetic polymers, and natural gums kno~n to the art of tablet making are ~uitable for the practlce of the invention. The organic liquld can be any havlng suitable solvent power and boiling in the range of fr 40-140~C.
COATING
The coating maeerlal is capable of forming a continuou~ film around the core by the evaporation of solvent from the coating material.
It has the ability to withstand environmental conditions of the rumen, and the ability to expose the core materlal of the pellet in the environment of the abomasum~ Thus, the coating material should be resistant to pH
conditions of greater than about 5 for from about 6 to about 30 hours.
The coating material should release the core material after exposure to abomasum environmental conditions having a p~ of about 2 to about 3.3.
Release shoult occur within the r2sidence time in the abomasum or later in the intestinal tract but at least within a time period of 6 hours after contacting p~ 3.5 or less. The exposure of the core may occur by the coating beco~ing permeable to the contents of the rumen, such as by dissolving, disintegrating, or extensive swelling. The coating material 4~97 is physiologically accepeable, i.e., the coating ~aterial should not l~terfere wi~h the ruminant~' healthy or normal body fu cti ing.
Another requirement for the coating ma~erial is it8 ability to withs~and abrasion in handling and ~torage conditions of relatively high heat antlor humidity without a significant amount of blocki~g. It should have a sticklng temperature of greater than about 50C. Sticking temperature is defined as the temperature at which adheslon sufficient to cause rupture of the coating upon forceable separation between coated particles occurs when an applied force of 0.25 Rg/cm2 holds the particles in contact for 24 hours. Also, the coating material is preferably soluble or dlspersable ln organic solvent3 having boiling points of between about 40C. and 140C. to permit conventional coating processes such as spray coating to be used. Particularly suitable solvents include methylene chloride, chloroform, ethanol, methanol, ethyl acetate, acetone, toluene, isopropanol or mixtures of these.
The coating or fil~ forming material accorting to this invention include~ a mixture or blend of at least one polymeric substance, at least one hydrophobic ~ubstance, and at least one flake material. Generally, the more acidic and more soluble core materials require greater ratios of hydrophobic substance and flake material to polymeric substance, while more baslc ant less soluble core materials require lesser ratios of hydrophobic substance and flake material to polymeric substance within this range. The hydrophobic substar~ce and flake material are nor~ally dispersed in the polymeric ma~rlx. The hytrophobic subs~ance is normally present in amounts of between about 2 and about 40% and the flake material is normally present ln amounts between about 10 ant 200~, based on the weight of the polymeric material POL~ER
The polymeric substances which are useful in the coatings of -~ 30 thi~ invention include those which, in c~mbination with the hydrophobic substance describet hereinafter, are physiologically acceptable ant resistant to a pH of greater than about 5 but capable of releasing the core of the pellets at a pH of less than about 3.5, at the normal body temperature o~ rumlnants (37C.). The polymeric Rubstances include polymers, copolymers and mixtures of polymers andlor copolymers having basic amino groups in which the nitrogen content of the polymeric sub stance is between about 2 and about 14% and typical lecular weights between about S,000 and 300,000. The basic amino groups may be of the aliphatic type in which case they will contain from about 2% to about 10% by weight of nltrogen ln the basic amlno groups. The baslc amlno groups may also be of the aromatic type in which the basic amino groups are attached directly to the aromatlc ring, or are part of the aromatlc ring structure in which case they will contain from about 6~ to about 145' nitrogen in the basic amino groups. The polymeric substances are macromolecules of sufficient molecular weight to have film-forming properties when the polymer is deposited from a solution and after removal of a solvent, dispersing medium or on cooling from a melt.
Polymeric substances havlng the characteristlcs deflned herein include certaln modified natural polymers, homo- and interpolymers obtained by addition polymerization methods, ho - and copolymers obtained by condensation polymerization methodg and mixtures thereof. The polymeric 20 material is comprised of at least one polymer, copolymer, or blend of polymers selected from the group consisting of cellulose derivatives such as cellulose propionate morpholinobutyrate; containing addition-type monomeric moietles such as acrylonitrile; vinylated derivatives of pyridlne; fltyrene; methylstyrene; vlnyl toluene; esters and amides of methacrylic acid; esters and amides of acrylic acid; polymerizable ethylenically unsaturated aliphatlc hydrocarbon monomers such as ethylene, propylene or butadiene; vinyl esters such as vinyl acetate, vinyl propionate or vinyl stearate; vinyl ethers such as methyl, ethyl, propyl or stearyl, vinyl substituted heterocyclic ring or condensed ring compounds containing 30 basic nitrogen configurations such as vinyl carbazole, vinyl quinoline, N-vinylpyrrole and 5-vinyl pyrozoline; containing condensation-type polymers wherein a diacid such as phthalic, terephthalic, and succinic .

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are combined with polyfunctional alcohols to form polyesters wherein either the acid or glycol moiety may conta~n basic Qit~ogen not reactive in the polymerization process but reactive to variable pH environments and wherein the same sr similar diacids may be reacted with polyfunctional amines to form polyamide-type polymers containing basic nitrogen not reacted in the polymerization process; and other basic nitrogen containing polymers such as preformed polymers which have been formed by reacting an existing polymer with a nitrogen containing organic or inorganic moiety such as polybutadiene to which ammonia has been reacted with the remaining double bond. Especially preferred are poly(vinylpyridine), polymeric derivatives of vinyl-pyridine, and the copolymers of the various isomers and derivatives of vinylpyridine copolymerized with one or more of the above-mentioned addition type monomers.
A160, especially preferred are copolymers of 2-methyl-5-vinyl-pyridine and styrene, and in particular, the copolymer of about 75-85% by weight 2-methyl-5-vinylpyridine and about 15-25% by weight styrene, as well as the copolymer of 55-65% by weight 2-methyl-5-vinylpyridine and about 35-45% by weight acrylonitrile. These copolymers are commerciAlly avail-able or may be produced by conventional techniques well known in the art.
~ HYDROPHOBIC SUBST~CE
Hydrophobic substances which are physiologically acceptable and have the correct degree of compatability with the polymer are commercially ; available. It is important that the polymer and hydrophobic substance have a degree of compatability to permit the film to remain intact in the rumen environment, but to permit permeation of the abomasal fluld to the core while the pellet is in the abomasum.
While we do not wish to rely on any particular theory as to ,. . .
why the coatings containing the hydrophobic substance are better protective, we believe the function is generally that the cverall susceptibility of the matrix films to aqueous weakly acidic environments is reduced.
Further, we believe that in view of the inherent polar nature of polymer5 containing enough basic nltrogen groups to be functional with respect to 44~7 the differences of rumen and abomosum p~. that a reduction in water susceptibility of the film is required, especially when the core material is acidic and/or very water soluble. Uhile the general theory believed to be true is as described above, there are subtle variations in the precise mode by which the hydrophobic substance is functional. A clas~
of hydrophibic substances of value are fatty acids containing from 10 to 32 carbon atoms such as lauric, oleic, stearic, palmitic and linoleic.
These substances are well known to be water insoluble due to the long hydrocarbon radical but to react to water due to the polar nature of the carboxyl group. In the selected basic amino group-containing polymers, the carboxyl group of the fatty acid is able to react with the basic nitrogen group to form a weak salt-type linkage. This attachment to the polymer serves to cause the fatty acid to be fixed in the polymer matrix.
The hydrophobic hydrocarbon chain of the fatty acid tends to render the matrix water resistant and thereby decreases swelling of the otherwise water suseptible polar film Both the interior of the matrix film and the surface is now water resistant in aqueous environments at pH above about 5Ø However, at pH values below pH 4.5 and especially below about pH 3.5 the affinity of the basic nitrogen group for water and the hydrogen ion overcomes the increased water resistance. The film reacts with the acid environment and loses barrier properties sufficient to allow the core material to escape to the environment.
Polyfunctional carboxylic acids may be derived from natural products or obtained by organic synthesis but the ratio of carboxyl group to hydrophobic organic radical should be at least 1 to 10 based on the molecular weight of the organic radicals. Also included in this class of synthesized organic hydrophobic acids are mono and poly-functional acids containing silicone or flourinated carbon groups located at least 4 atoms distant along the molecular chain from the position of the carboxyl group or groups. Also, included in the class of hydrophobic substances are the nontoxic multivalent metallic salts of the above acids such as the stearates, oleates, fatty acid dimerates, and palmitates .
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of aluminum and iron and the calcium, magnesium and zinc salts of the higher molecular ~eight crystalline analogs of the above acids. When the cation is trivalent as for alumlnum and ferric iron, the molar ratio of organic acid to metal ion is 2 to 1 or 3 to 1 and the acid can be any monofunctlonal organic acid h~ving one carboxyl group and at least 10 carbon atoms in the organic radical attached to the carboxyl group.
When the metal ion is divalent such as ferrous iron, calcium, magnesium or zinc the organic acid may be monocarboxylic or polycarboxylic ant the ratio of metal ion to non-carboxylic carbon atoms is at least 1 to 26.
Na~ural and synthetic waxes and resins added at levels depending on the degree of hydrophobicity and compatibility in the matrix film are of value in the practice of the inventlon. Waxes and resins are useful - that have a molecular weight of from 500 to 2000 and a critical surface tension of less than 31 dynes/cm as determinet by the Zisman method described in "Contact Angle Wettability and Adhesion", Advances in Chemistry Series #43; Edited by Robert F. Gould: published by the American Chemical Society; 1963; Chapter l; and have a solubility in the matrix film of less than 5~. These waxes and resins are dispersed in the film in at least amounts equal to 2 times the solubility and up to 30% of the total weight of the matrix polymer. Typical waxes and resins include ; beeswax, petroleum wax, dammar, hard manila, phenolic resins, rosin and maleated low molecular weight polyhydrocarbons. Also included in the hydrophobic substances are polymers having molecular weights of from 2000 to 10,000, a critical surface tension of less than 31 dynes/cm : measured by methods in the reference to Zisman described above. Useful polymers have a solubility or compatibility in the matrix film of less than 5% on a weight basis and are present in the film at levels at least equal to two times the solubility and up to 30 weight percent of the matrix film. Of particular value are the polymers and copolymers containing silicone groups in the main polymer chain or in a side chain and polymers and copolymers containing flourinated carbon groupq in a side chain.

Regardless of the exact nature of the hydrophobic substance it must be soluble or colloidally dispersible in the coating solvent when one is used. The hydrophobic substance makes up from 1 to about 50% of the combined weight of polymeric material and hydrophobic substance.
Suitable hydrophobic substances also include fatty acids having from 12 to 22 carbon atoms, such as oleic acid and stearic acid, dimer acids, trimer acids, aluminum salts of fatty acids, waxe~, resins, and certain polymers such as polymers containing very hydrophobic chemical groups such as silicone moieties and certain multivalent catlon soaps.
The hydrophobic substance may be amorphous or crystalline and preferably 1~ essentially dispersible in the coating solvent when a solvent is used in which case it should not contribute significantly to the solution viscosity.
Aluminum salts of such acids, for example, aluminum oleates, aluminum stearates, aluminum dimerates, are also useful. Also, the hydrophobic material may be one or more polycarboxylic acids having a ratio of from 10 to 22 carbon atoms per carboxyl group and a molecular weight greater than 300, preferably about 400 to about 1000, are useful, Blends of these acids and/or sales are also useful.
We believe the function of the hydrophobic substance as a dispersed phase in the protective polymer layer:
a. reduces wetting of the coating and therefore initial attack by water, b. reduces total volume of coating affected by water, and c. e~tends the length of permeable pathway the water must travel to core.
FUNCTIONAL FLAKE MATERIAL
In accordance with this invention, a physiologically acceptable flake material is dispersed throughtout the polymeric matrix. The flake material is substantially inert with respect to the environment of the rumen.
Suitable inert flake materials include metal flake, mineral flake, crosslinked organic polymer, etc. Especially suitable are aluminum flake, talc, graphite, and ground mica.

-APPLICATIO~ OF COATI~G
In the practice of his invention, the polymeric material ~ay conveniently be dissol~ed in a suitable organic solvent which would be ?hysio'ogically acceptable in the event there are residues upon evaporation of the solven~, as hereinbefore described. The hydrophobic substance is blended in the solution, wherein the polymeric substance i9 a continuous matrix and the additives are dispersed therein. The coating solution may be applied by various well known means such as, for example, brushing, dipping, spraying, fluidized bed, etc.
A preferred apparatus and process for coating the cores will now be described.
In the drawings:
Fig. 1 is an elevation view in cross~section illustrating the apparatus and showing the gas flows and particle flow path from the annular bed to and through the truncated hollow cone and in return to the annular bed;
: Fig. 2 ls a partial elevation view in cross-section of a modified apparatus and illustrating the addition of an annular airfoil and showing the flow of gases relative to the aerodynamic structure and annular airfoil;
Fig. 3 is a partial elevation view in cross-section of another modified apparatus similar in all other respects to the modification shown in Fig. 2 except that the cross-section of the apparatus below the coating chamber is of the same dia~eter as that of the coatin~ chamber-Fig. 4 is a partial elevation view in cross-section of the upper portion of the apparatus of the invention for illustrating one possible manner of collecting the finally coated particles by use of an air porous bag; and Fig. 5 is a graphic illustration of the height, thickness and angular relationships of the annular airfoil with respect to the aero-dynamic structure, and the height above (ha) and height below (hb) relationships of the aerodynamic structure to the greatest cross-sectional diameter of the-aerodynamic structure.

- la -il~4~7 The apparatus employs a truncated hollow cone in which the slope or pitch of the walls is such that the particles are accelerated at an increasing rate and noe just at a rate so as to maintain the gas velocity at any given point in the cone at a level greater than that necessary to move .he particles in a continuous upward direction. The slope or pitch of the walls would therefore appear to be more pronounced than the slope or pitch of the cone embodiment disclosed in the Larson et al patent. The significance of the slope or pitch of the truncated hollo~ cone of the invention is that when a particle first enters the cone at one rate of speed, it is then accelerated to a different rate of speed and continues to be accelerated to still different rates of speed as it moves upwardly through the cone. In this manner a separation is brought about between the particles so that after they are coated they may become sufficiently dry before coming into contact with other particles and thereby avoid undesirable clumping or agglomerating together. The pitch of slope is such as to cause a compression of the gas molecules and thereby cause the acceleration at an increasing rate.
In reference to Fig. 1, the coating apparatus is designated in general at 10 and includes a vertically disposed first hollow column 12 Of regular shape. By "regular shape" is meant that it may be cylindrical, octagonal, hexagonal or of other configurations, so long as the hollow column is generally symmetrical with respect to its central axis. The hollow column contains therewithin the particle storage, coating, drying and deceleration zones, which will be described herein.
A truncated hollow cone 14, which may also be a tapered octa~on or other tapered polygonal configuration, in other words, generally cone-shaped configurations, serving as an enclosure in which the upwardly flowing gases are received, co~pressed and accelerated, is centrally disposed within the first hollow column, has a uniformly decreasing cross-section in the upward direction and is of predetermined helght dependent upon the size and weight of the particle to be treated.
Within the truncated hollow cone in ascending order are the coating and drying zones. The cone serves also to separate the coating and drying :

zones from the deceleration zone, which 11es in the region above the upper end of the cone, and from the storage zone, which li2s therebetween the cone and the interior wall surface of the first hollow column.
The first hollow column 12 is provided at its lower end with an inwardly tapered base 16. The lower end of the truncated hollow cone is spaced radially inwardly flom the inwardly tapered base.
A second vertically disposed hollow column 18 of regular shape is connected to the inwardly tapered base of the lower end of the first hollow colu~n, the wall surface of the inwardly tapered base forms a ~uncture with the wall surface of ehe second hollow col = .
Disposed within the second hollow column is a first plenum chamber 20 into which a suitable compressed gas, such as air, may be provided through two or more opposed inlets 22, 24: a gas or air colli-mating plate 26; a second plenum chamber 28 separated from the first plenum chamber 20 by the collimating plate 26; at least one gas shaping or aerodynamic structure 30 disposed within the second plenum chamber; and a particle support or supporting screen 32, which extends across the second hollow column and is located above the aerodynamic structure.
The gas or air collimating plate 26 is a perforated plate 20 which causes the gas or air in the first plenum chamber to pass into the second plenum chamber in an zssentially vertical and uniform flow, a~
lllustrated by the vertical arrows.
The gas shaping or aerodynamic structure 30 in cooperation with the ad~acent wall surface of the second hollow column, compresses and focuses the upwardly moving gas or air flow so that it flows over a portion of the surface of the aerodynamic structure, upwardly through the particle support screen and into the entrance end of the truncated hollow cone. The flow upwardly around the aerodynamic st~ucture constitutes an annular flow, which adheres to the surface of the aerodynamic structure 30 in the nature of a Coanda flow.
A spray nGzzle 34 preferably extends above the top of the aerodynamic structure 30 through which is sprayed a suitable coating material. It is more conv~nient to have the spray nozzle located at the top of the centrally disposed aerodyn~mic structure. The coating materialis supplied from a suitable source (not shown) through a cond~it 3~
extend~ng up through the aerodynamic struc~ure, and an atomizing gas may be supplied from a suitable source (not shown) through a conduit 38, also extending up through the aerodynamic structure, for subsequent mixing at the nozzle. The spray nozzle may also be pressure-operated rather than gas-operated.
The upper surface of the gas shaping or aerodynamic structure is centrally disposed within and extends generally horizontally across the cross-section of the vertically disposed hollow column. In other words, it has a cross-sectional plane generally perpendicular to the vertical axis of the vertically disposed hollow columns. The outer edge of the upper surface i9 equally spaced from the wall surface of the hollow column and defines therebetween with the wall surface of the hollow column a reduced pressure region for acceleration in velocity of the ùpwardly flowing gases in such manner that the upwardly flowing gases form a boundary layer that is directed away from the wall surface of the hollow column and that adheres to the upper surface of the gas shaping or aerodynamlc structure for flow across a portion thereof.
The upper surface of the aerodynamic structure may be flat (not illustrated), but is preferably curved or approximately spherical as illustrated. It may have a height (ha) above the cross-sectional plane (See Fig. 5), therefore, of from about 0% to about 150~, or preferably from about lQ% to about 150% of the greatest cross-sectional diameter (D) (See Fig. S) of the aerodynamic structure.
The surface below the greatest cross-sectional diameter may also be flat (not illustrated) and may therefore have a depth or height (hb) below of from about 0% to about 200% of the greate-~t cross-sectional diameter (D) (See Fig. 5). Preferably, the surface below is formed in the manner disclosed in the drawings.
The aerodynamic structure as disclosed and as described is thus adapted to compress and accelerate the flowing gases near the periphery of the hollow column and direct them ~oward the center of the hollow column at an angle from about 10~ to about 45 from a directionparallel to the flowing gases from the gas or air plenums.
The truncated hollow cone defines at its lower end a large diameter somewhat smaller than the diameter of the vertically disposed first hollow column, and has an increased diameter from about 0% to about 25~ greater than that of the plane of the particle support screen.
The lower end of the truncatet hollow cone is spaced a predetermined amount from the screen and the upper end defines a diameter of from about 20Z to about 80~ of that of the lower end. The height of the cone ranges from about one to about six times the diameter of the lower end.
In operation, particles 40 may be suitably loaded into the coating apparatus 10, as through a closable opening at 42, into the storage zone lying between the wall surface of the first hollow column 12 and the outside wall surface of the truncated hollow cone 14. The particles are thus situated in an annular bed around the truncated hollow cone 14. The sloping outer wall surface of the truncated hollow cone, the inwardly sloping tapered base 16 of the first hollow column and the screen 32 serve to contain the particles in the annular bed prior to starting-up the coating operation.
The gas or air is turned on to start the circulation of the particles or pellets from the annular bed or storage zone into the coating, drying and deceleration zones and in return to the upper portion of the annular bed. The atomizing spray is then turned on and appro-priately adjusted in a suitable manner by controls (not shown~.
As previously pointed out, the Coanda flow or effect is named for the tendency of a fluid, either gaseous or liquid, to cling to a surface that is near an orifice from which the fluid emerges. Such "orifice" in this instance is formed in the region therebetween the closest approach of the aerodynamic structure to the adjacent side wall ` 30 surface. The gas flow emerging from the "orifice" region around the aerodynamic structure is an annular flow which clin~s or adheres to the surface of the aerodynamic structure. The flow, therefore, from any one selected location around the "orifice" is opposed by the other flows so that it is prevented from continuing further over the upper surface of the aerodynæmic structure by being forced upwardly away from the uppes surface at some point for flow into the truncated hollow cone. A
partial vacuum is formed in the reglon ~ust above the upper surface of the aerodynamic structure and at the lower edge of the truncated hollow cone and this aids in the compression and focusing of the rising annular flow of gases. The upward flow is consequently caused to have a conical shape, as seen in phantom lines in Fig. 1 at 44 within the cone, and has a centering effect on the particle impelled upwardly through the cone.
As also pointed out, an important part of the Coanda effect is the tendency of the flow or gas or liquid to entrain, or draw in, more gas or liquid from the surrounding environment. In this latter manner, the particles are pulled from the annular bed or storage zone into the upwardly flowing gas due to the aforementioned partial vacuum or reduced pressure region that exists just above the screen ad~acent the path of upward flow as a consequence of this Coanda effect. This reduced pressure or partial vacuum i8 directed perpendicular to the annular airflow from the "orifice". It is a different effect, however, from the horizontal shunting action occurring in the Wurster et al apparatus described above because there the horizontal shunting would extend not only toward the axis of the apparatus but also inefficiently toward the outer wall surface of the coating apparatus.
Once the particles are pulled into the upwardly flowing gas within the truncated hollow cone, they are impelled upwardly in an accelerating gas or air stream. As the particles pass through the lower central region or coating zone within the cone, they are contacted with an atomized spray coating of material. This atomized spray emerges from ; the spray nozzle 34 because the liquid coating substance is either forced through a single orifice designed to convert bulk liquids into 30 droplets, or the llquid and an atomizing air stream emerge simultaneously from ~ets ad~acent to each other. In either case, the fine droplets of coating material are in a flowable state, because the material is dissolved llQ~9~

or melted in the region immediately above the spray nozzle.
Further up the truncated hollow cone, the liquid nature of the coating material, as deposited on the pellets or particles, changes to solid by evaporative or other solidification processes. During the transition from l$quid to solid, the coated particles pass through a stage when they are sticky or tacky and would agglomerate lf they contacted each other. This contact is prevented by the slope or pitch of the walls of the truncated hollow cone and consequent accelerating boost of the particles to separate them in the manner previously discussed.
The conical nature of the cone causes a compression and accelera-tion of the rising column of gases and the upward velocity or accelera-tion of the particles occurs at an increasing rate as they rise in the cone. This acceleration causes an increasing vertical separation in space between the particles and therefore reduces the tendency for the particles to contact each other until the coating has become nontac~y.
It i~ this region of the cone that is thus called the "drying zone".
When the compressed gases and entrained particles pass upwardly out of the upper end of the cone, they expand into the larger area of the upper portion of the first hollow column and thus decelerate to a velocity too low to suspend the particles. This is the deceleration zone, where further drying takes place, and the particles then fall by gravity action to the annular bed where they gradually move down, also due to gravity, until they are pulled into the coating zone again. This recycling or recirculation continues until, based on previous experiments, a sufficient coating has been applied.
; The atomized spray is turned off, and the gas or air entraining flow may be shut down or may be increased to drive the coated particles into the uppermost region of the first hollow column, as for collection in the manner illustrated in Fig. 4. Any other suitable manner of 30 unloading the finally coated particles may also be used.
A c~ating apparatus having the design characteristics essentially as shown in Fig. 1, and having a diameter of eight (8) inches across the ~4~

lower end and four (4) inches across the upper end of the truncated hol-low cone, is charged with twenty-five (25) pounds of generally spherlcal pellets of animal feed supplement. The pellets are composed of 90~
methionine and 10~ binders. The average diameter of the spherical pellets is about 3 millimeter. About 250 standard cubic feet per minute of air at about 7 p.s.i.g. is admitted to the plenum chamber 20. This air causes a circulation of pellets through the truncated hollow cone 14, and the height of the cone above the support screen 32 is adjusted to obtain a pellet flow rate such that all the pellets in the annular storage zone move through the cone about once every minute. A coating solution i8 pumped through the spray nozzle 34 at the same time as 5 SCFM of atomizing air at 40 p.s.i.g. is supplied to the nozzle. The pumping rate is ad~usted to pump one (1) pound of solution per minute. The apparatus ls operated for about 45 minutes. The product is a pellet core coated with about a 2-mil layer of the polymer.
If the gases flowing upwardly around the aerodynamic structure could be seen as a series of layers of molecules, merely for sake of dlscussion, it is thought that there is an insignificant flow of molecules or layer or so cf molecules along the interior wall surface of the ; 20 second hollow column. By "insignificant" is meant that such layer or layers of molecules will not perfcrm any supporting function of the particles in the annular bed.
Moving, therefore, radially inwardly from the interior wall surface of the second hollow, the more significant layers of molecules are caused to bend toward the gas shaping or aerodynamic structure, the innermost adhering to the surface of that structure as they pass upwardly through the "orifice" region. This adherence of the molecules to the surface of the aerodynamic structure may be favorably compared to the "teapot effect", which is a low-speed form of the "Coanda effect". When water is poured slowly from a glass, it tends to stick to the side of the glass in the same way that tea sticks to the spout of a teapot.

Hlgh speed fluids behave similarly and adhere to a surface of suitable shape.
As the rlsing molecules flow over the surface of the aerodynamic structure after having passed the "orifice" region, previously mentioned, at some polnt along the upper surface of the aerodynamic structure the opposing character of the annular flow forces the molecules upwardly away from the upper surface as well as the ad~acent molecule layers. A
partial vacuum is created above the aerodynamic structure due to the high speed upward flow of gases, causing an inward bending of the upwardly moving molecules.
In the apparatus herein described, the particles move down in the annular bed by gravity without any "dancing" occurring, and are drawn into the upwardly flowing gases by the partial vacuum. Thus, any attrition that might occur is greatly minimized, and the overall opera-tion is much more efficient.
In reference to Fig. 2 in which a modification is disclosed, the same reference numbers will be used to identify similar elements previously described, except that they will be primed to show that it is a different embodiment under discussion.
Fig. 2 represents an embodiment wherein the size of the coating apparatus 10' has been increased in order to handle larger batch loads of particles for coating treatment. It has been found that it is more practical to add an additional gas shaping or aerodynamic structure or an annular airfoil 50 instead of increasing the size of the aerodynamic structure 30'. In this manner, larger amounts of upwardly flowing gas or air may be supplied undiminished or unobstructed by a larger aero-dynamic structure, and the annular airfoil serves to supplement the com-pression and focusing action on the upward gas flows so that substantially all gas flows move through the truncated hollow cone 14'.
Additional or multiple gas shaping or annular airfoils (not shown) also may be used for still larger coating apparatus. The exact shape and placement of the airfoils are functions of a number of variables.
The most significant of the variables are size of the apparatus, size of ~he particle to be coated, density of the particle, rate of gas or air flow and the rate of recirculation of the particles through the coating zone desired.
In a larger-scale coating apparatus, therefore, one or more annularly shaped and placed gas shaping or aerodynamic structures or airfoils, angled or curved, may be provided concentric with and radially outwardly of the central gas shaping or aerodynamic structure. The annular airfoils may be attached to the central aerodynamic structure or to the walls of the coating apparatus by radial struts in such manner as to exert a minimum deflection of the upwardly flowing gases.
The annular aerodynamic structure is inwardly inclined in the upward direction so that its inclination lies in a plane extending about 10 to about 45, as measured from the axis perpendicular to the diameter of the coating apparatus. The inwardly inclined annular structure provides a surface on which the gas or air impinges for subsequent shaping and direction upwardly into the truncated hollow cone.
The vertical height of the annular structure may be about 10-50% of the perpendicular cross section diameter of the coating apparatus.

In reference to Fig. 5, when the annular gas shaping structure has the configuration of an airfoil havlng at least one curved surface extending generally in the directlon of gas flow, the overall angle of a line descrlbed from a point Pl, on the lower rim of the airfoil to a point, P2, on the upper rim in the vertlcal direction, or perpendicular to a line whlch is tangent to the upper curved surface of the centrally disposed aerodynamic structure, ls from about 10 to about 45 inward facing, as measured from the axls perpendicular to the diameter of the coating apparatus.
The cross-sectional configuration of an annular airfoil in a plane described from the center of the cross-sectional area of the coating apparatus to a point, Pl, on the lower rim of the airfoil to a point, P2, in the upper rim of the airfoil is teardrop, or similar to the cross-sectional shape of a lifting aerodynamic shape, and having the thicker cross section on the forward part w$th reference to the direction facing the upwardly flowing ga~es. The thickest part is located about two-fifths (2/5) to about one-half (1/2) of the height in the vertical direction. In other words, the height (~1) of the thickest part (T), or HT is equal to about 2/5 H to about 1/2 H. The thickest cross cection (T) is from about one-sixth (1/6) to about two-fifths (2/5) of the height (H) of the airfoil; or T is equal to about 1/6 H to about 2/5 H.
The size, placement and geometrical configuration of the annular gas shaping structure are such, therefore, that the upwartly flowing gases are deflected radially inwardly at an angle from about 10 to about 45 from a direction parallel to the original gas flow.
In reference to Fig. 3, the same reference numbers will be used to identify similar elements previously described, except that they will be double-primed to ~,how that it is still another different embodi-ment under discussion.
Fig. 3 represents an embodiment wherein the size of the coating apparatus 10" has been increased to the same extent as that disclosed in the Fig. 2 embodiment. The embodiment in Fig. 3 differs from the embodiment in Fig. 2 in that the first and second hollow columns are disclosed as being co-extensive in cross-sectional diameter. In other words, the coating apparatus is disposed within a single hollow column.
It could also be of smaller size so that only one gas shaping or aero-dynamic structure 30'' is employed as in Fig. 1, instead of a size requiring the annular airfoil 50".
The recycling or recirculation in this embodiment is necessarily faster because the particles are not as readily restrained in the annular bed region as they would be if there were an inwardly tapered base to assist in such restraint. Proportionately smaller batch loads may be used, therefore, since the recirculation of the particles is substantially continuous with the particles spending very little time in the annular bed. For this reason, an embodiment of this character is suitable for special purposes, whlle the embodiments of Fig. 1 and Fig. 2 are deemed to be of more general use.
In Fig. 4, this embodiment represents one manner of unloading a coating apparatux, and was briefly mentioned above with respect to one posslble operation of the embodiment of Fig. 1.
Only the upper portion of a coating apparatus 60 ls shown, and it could be used for any of the previously described embodiments. A
conduit 62 is installed within the upper portion of the appsratus, as shown, and a gas or air porous collection bag 64 may be installed at the remote end of the conduit for collecting the finally coated particles in the manner already heretofore described.
In any of the embodiments described above, the truncated hollow cones may be adapted to be adjusted for movement upwardly or downwardly in a vertical plane. The same may also be accomplished with the aero-dynamic structure, the annular airfoils and the spray nozzles, as desired to suit gas or air flows, particle sizes and weights, coating material consistencies and whatever other controlling factors may be concerned.
The particles or pellets to be coated may be batch-loaded and treated; or, if deemed advantageous, two or more such coating apparatus may be arranged in cascaded manner to provide for a continuous coating operation. Tne inlet for the particles in a cascaded arrangement may be diposet above the annular storage of one apparatus and the particles metered in predetermined manner into the annular storage bed, while the outlet to the next coating apparatus may be disposed on the opposite side of the annular storage bed and constitute a weir for outflow of excess coated particles. The inlet may also be disposed for gravity flow of particles to or into the annular storage bed. It may be desir-able to provide for different coatings in different apparatus, or provide supplemental coatings.

. .
Multiple spray nozzles may also be employed, as desired, to achieve different coating effects.

The examples which follow are submitted for a better understanding of the invention. While the examples are based on in vitro tests, the in vitro experiments shown in the examples simulate conditions existing in ruminants thereby permitting the study of coated pellets without the use of live animals. lt has been determined by actual in vivo tests that the testing of pellets in the aqueous media used in the examples, simulating the environmental conditions of the rumen and abomasum with reqpect to temperature, pH, etc., provide reliable data concerning the protection offered by the coatings in the rumen, and releasability of the coatings in the abomasum. Nutrients such as amino acids and proteins which may be used in the core material are known to be beneficial to ruminants when positioned in the intestinal tràct downstrea~ from the rumen.
The following examples are submitted for a better understanding of the invention. Generally, pellets are prepared from the nutrients indicated to a size of between about 8 and 12 sieve size. ~he nutrients are mixed with conventional additives such as microcrystalline cellulose, binders, inert consistency ad~usting substances such as water, etc. The pellets are formed by a conventional pelletizer, dried, sieved, and coated using a coater as described herein. Upon formation of an imperforate coating on the pellets, they are tested for resistance to pH conditions resembling those of the rumen and abomasum by agitating in buffer solutions of pH 2.9 for 0.5 hours and 5.4 for 24 hours. Recovery and protection figures cited for active core ingredients herein contain in them all materials of the original coated pellet that are not completely dissolved in the pH 2.9 buffer, including any undissolved active ingredient in the - original core. For the sake of simplicity, abbreviations are used in the examples as follows:
2M5VP - 2-methyl-5-vinylpyridine AN - acrylonitrile Where coating ratios are used, the first number indicates the number of parts polymer7 the sec~nd number indicates the number of parts hydrophobic substance, and the third number indicates the number of parts inert flake material. In Table II, a coating ratio of 70/30/1~, wherein the flake material is aluminum or graphite, i9 used. In Table I, 25% of the hydrochloride of the lycine.HCl is neutralized using calcium carbonate. Dimer Acid 1010 ls a trademark for dimer acid marketed by Emery Industries.
TABLE I
Protection Achieved on Lysine HCl Pellets with Coating Combinations of 60/40 2M5VP/AN
CoPolymer, Dimer Acid 1010 and Aluminum Powder Example Coating Combination % % Recovered From No Ratio Coating pH 2.9 pH 5.4 1 70/20/10 18.8 24.3 83.7 2 70/20/20 19.8 23.3 84.2

3 70/20/30 19.8 23.1 88.5

4 70/30/10 20.0 -- 82.9 70/30/20 19.9 -- 89.9 6 70/30/30 21.2 17.6 90.3 7 70/30/30 19.1 20.6 79.0 Graphite replaced aluminum in coating combination.
TABLE II
Recovery of Coated Glucose Pellets ExampleRatio of 2M5VP ~ % Recovered From No. to AN Coating pH 2.9 pH 5.4 8 85/15 15.6 12.8 87.7 9 80/20 17.8 20.8 95.5 75/25 16.2 14.5 95.2 11 70/30 16.6 13.3 88.8 12 60/40 16.2 12.2 92.3 . . .
13 50/50 16.7 10.4 80.8 Table III compares results obtained using actual abomasal and duodenal fluid extracted from a ruminant wlth artificial test fluid. In this table, the polymeric material used is an 80/20 copolymer of 2-methyl-

5-vinylpyridine and st~rene (I.V. = 1.23). The core material is 90.9~

:
- 3~ -il~?~

methionine, 3.6% sodium carboxymethyl cellulose and 5.5X sucrose. The pellets are made by first dry mixing 500 g. of methionine, 20 g. sucrose and 10 g. sodium carboxymethyl cellulose. Water (135 g.) is added and mixed to obtain an extrudable wet powder. The mixture is extruded and chopped to obtain pellets to pass 8 mesh screen and remain on 12 mesh. Ten grams sucrose ant 10 g. sodium carboxymethyl cellulose are dry mixed, and added to the wet pellets. The pellets are then tumbled to obtain a uniform coating. Tumbling is continued in hot air to obtain dry pellets.
The coatings are made using the ingredients indicated dissolved or quspended in acetone at 5% solids level. An air suspension coater is used to coat the pellets.
In the examples, the coating comprises 31.5% polymer, 3.5% stearic acid, and aluminum flake and talc as indicated. Ten percent coating, based on the weight of the core, is used. pH of the abomasum simulated fluid is 2.9. pH of the rumen simulated fluid is 5.4. Release is measured after one hour periods.

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~ ne invention therefore provides a pellet adapted for oral administration to a ruminant comprising a core material beneficial to the ruminant postruminallyl and a coating surrounding said core material, said coating comprising a) a film-forming polymeric material containing at least one basic amino grouping and in which the nitrogen content is from 3 to 14% by weight of the total molecular weight of the polymeric material, said polymeric material comprising at least one polymer, copolymer or blend of polymers selected from the group consisting of cellulose propionate morpholinobutyrate, aromatic basic amino-containing polymers, dialkylamino etbyl acrylates and methacrylates in which the alkyl group contains from 1 to 6 carbon atoms, condensation polyesters and polyamides, b) from about 2 to 50%, based on the weight of said polymeric material, of a hydrophobic material dispersed in said polymeric material selected from the group consisting of waxes, resins, polymers, fatty acids having from 12 to 32 carbon atoms, aluminum salts of fatty acids having from 12 to 32 carbon atoms, and polyfunctional carboxylic acids having a ratio of from 10 to 22 carbon atoms per carboxyl group and a molecular weight of from 400 to 1000, and c) from about 10 to 200%, based on the weight of said polymeric material, of a physiologically acceptable flake material dispersed in said polymeric material, and said coating making up about 5 to about 50% of the weight of said pellet, and having a sticking temperature of at least about 50C.
~ne fluid used to simulate environmental conditions of the 30 rumen (at pH 5.5) is prepared by mixing 11.397 grams of sodium acetate witb 1.322 grams of acetic acid and diluting this mixture with de-mineralized water to I liter.

L~

4~37 ~ ne fluid used to simulate environmental conditions of the abomasum (at pH 2.9) is prepared by mixing 7.505 grams glycine with 5.85 grams sodium chloride and diluting tbis mixture with deminerali2ed water to I liter. Eighnt parts of this solution are mixed with 2 parts of 0.1 normal hydrochloric acid for the test fluid.
~ ne fluids are found to give reliable results in testing the pellets, according to similar experiments using actual rumen and abomasal fluid withdrawn from a ruminant.
Unless otherwise specified, all ratios, percentages, etc., are by weight.
To be useful and practical as a feed for ruminants, it is considered that at least 60% and preferably at least 75% of the active ingredients of the core of the pellets to which this invention relates should be stable in the rumen and release in the abomasum.
The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

- 34a -

Claims (22)

We Claim:

1. A pellet adapted for oral administration to a ruminant comprising a core material beneficial to the ruminant postruminally, and a coating surrounding said core material, said coating being resistant to pH conditions of about 5.5 for at least six hours and adapted to release pellet core material after exposure to a pH of about 3.5 after a time of from about 10 minutes to about six hours and comprising a) a film-forming polymeric material containing at least one basic amino grouping and in which the nitrogen content is from 3 to 14% by weight of the total molecular weight of the polymeric material, said polymeric material comprising at least one polymer, copolymer or blend of polymers selected from the group consisting of cellulose propionate morpholinobutyrate, aromatic basic amino-containing polymers, dialkylamino ethyl acrylates and methacrylates in which the alkyl group contains from 1 to 6 carbon atoms, condensation polyesters and polyamides, b) from about 2 to 50%, based on the weight of said polymeric material, or a hydrophobic material dispersed in said polymeric material selected from the group consisting of waxes, resins, polymers, fatty acids having from 12 to 32 carbon atoms, aluminum salts of fatty acids having from 12 to 32 carbon atoms, and polyfunctional carboxylic acids having a ratio of from 10 to 22 carbon atoms per carboxyl group and a molecular weight of from 400 to 1000, and c) from about 10 to 200%, based on the weight of said polymeric material, of a physiologically acceptable flake material dispersed in said polymeric material, and said coating making up about 5 to about 50% of the weight of said pellet, and having a sticking temperature of at least about 50°C.

2. A pellet according to Claim I wherein said polymeric material comprises at least one polymer selected from the group consisting of cellulose propionate morpholinobutyrate, and polymers, copolymers and blends of polymers selected from the group consisting of acrylonitrile, vinyl pyridine, styrene, methacrylate and methyl meth-acrylate.

3. A pellet according to Claim I wherein said hydrophobic material is selected from the group consisting of fatty acids having from 12 to 32 carbon atoms, aluminum salts of fatty acids having from 12 to 32 carbon atoms, and polyfunctional carboxylic acids having a ratio of from 10 to 22 carbon atoms per carboxyl group.

4. A pellet adapted for oral administration to a ruminant comprising a core material having a pH greater than about 5.68, said core material being beneficial to the ruminant postruminally, and a coating surrounding said core material, said coating being resistant to pH conditions of about 5.5 for at least six hours and adapted to release pellet core material after exposure to a pH of about 3.5 after a time of from about 10 minutes to about six hours and comprising a) a film-forming polymeric material containing at least one basic amino grouping in which the nitrogen content is from 3 to 14% by weight of the total molecular weight of the polymeric material, said polymeric material consisting essentially of cellulose propionate morpholino-butyrate, and polymers, copolymers and blends of polymers derived from monomers selected from the group consisting of 2-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinyl-pyridine, and 2-ethyl-5-vinylpyridine.
b) from about 2 to about 40% based on the weight of said polymeric material, of a hydrophobic material dispersed in said polymeric material selected from the group consisting of fatty acids having from 12 to 32 carbon atoms, aluminum salts of fatty acids having from 12 to 32 carbon atoms, and polycarboxylic acids having a ratio of from 10 to 22 carbon atoms per carboxyl group and a molecular weight of from 400 to 1000, and c) from about 10 to about 200%, based on the weight of said polymeric material, of a physiologically acceptable flake material dispersed in said polymeric material, said coating makes up about 5 to about 50% of the weight of said pellet, and having a sticking temperature of at least about 50°C.

5. A pellet according to Claim 4 wherein said core materials is selected from the group consisting of L or DL mixtures of isomers of alanine, arginine, methionine, tyrosine, phenylalanine, lysine and glycose.

6. A pellet according to Claim 4 wherein said core material is selected from the group consisting of glucose, bacitracin, thyrotropin releasing factor and inositol.

7. A pellet according to Claim 4 wherein said polymeric material is a copolymer of 2-methyl-5-vinylpyridine and styrene.

8. A pellet according to Claim 6 wherein said polymeric material is a copolymer consisting essentially of about 80% 2-methyl-5-vinylpyridine and about 20% styrene.

9. A pellet according to Claim 4 wherein said hydrophobic material is aluminum oleate.

10. A pellet according to Claim 4 wherein said hydrophobic material is stearic acid.

11. A pellet according to Claim 4 wherein said hydrophobic material is dimer acid.

12. A pellet according to Claim 4 wherein said flake material is selected from the group consisting of metal flake, mineral flake, and crosslinked organic polymer.

13. A pellet according to Claim 12 wherein said flake material is selected from the group consisting of aluminum flake, talc, graphite, and ground mica.

14. A composition adapted for use in coating pellets orally administrable to a ruminant, said composition being resistant to pH
conditions of about 5.5 for at least six hours and adapted to release pellet core material after exposure to a pH of about 3.5 after a time of from about 10 minutes to about six hours and comprising a) a film-forming polymeric material containing at least one basic amino group in which the nitrogen content is from 3 to 14% by weight of the total molecular weight of the polymeric material, said polymeric material consisting essentially of cellulose propionate morpholinobutyrate, and polymers, copolymers and blends of polymers derived from monomers selected from the group consisting of 2-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine, and 2-ethyl-5-vinylpyridine, and b) from about 2 to about 40%, based on the weight of said polymeric material, of a hydrophobic material dispersed in said polymeric material selected from the group con-sisting of fatty acids having from 12 to 32 carbon atoms, aluminum salts of fatty acids having from 12 to 32 carbon atoms, and polycarboxylic acids having a ratio of from 10 to 22 carbon atoms per carboxyl group and a molecular weight of from 400 to 1000, and c) from about 10 to about 200%, based on the weight of said polymeric material, of a physiologically acceptable flake material dispersed in said polymeric material.

15. A composition according to Claim 14 wherein said polymeric material is a copolymer of 2-methyl-5-vinylpyridine and styrene.

16. A composition according to Claim 14 wherein said polymeric material is a copolymer consisting essentially of about 80% 2-methyl-5-vinylpyridine and about 20% styrene.

17. A composition according to Claim 14 wherein said hydrophobic material is aluminum oleate.

18. A composition according to Claim 14 wherein said hydrophobic material is stearic acid.

19. A composition according to Claim 14 wherein said hydrophobic material is dimer acid.

20. A composition according to Claim 14 wherein said flake material is selected from the group consisting of metal flake, mineral flake, and crosslinked organic polymer.

21. A composition according to Claim 20 wherein said flake material is selected from the group consisting of aluminum flake, talc, graphite, and ground mica.

22. A pellet adapted for oral administration to a ruminant comprising a core material having a pH greater than about 5.68, said core material being beneficial to the ruminant postruminally, and a coating surrounding said core material, said coating being resistant to pH conditions of about 5.5 for at least six hours and adapted to release pellet core material after exposure to a pH of about 3.5 after a time of from about 10 minutes to about six hours and comprising a) a film-forming copolymer of about 80% 2-methyl-5-vinyl-pyridine and about 20% styrene by weight, b) from about 2 to about 40% based on the weight of said polymeric material, of a hydrophobic material dispersed in said polymeric material selected from the group con-sisting of aluminum oleate, dimer acid, stearic acid and oleic acid, and c) from about 10 to about 200%, based on the weight of said polymeric material, of at least one physiologically acceptable flake material dispersed in said polymeric material selected from the group consisting of talc, aluminum flake and graphite, said coating making up about 5 to about 50% of the weight of said pellet, and having a sticking temperature of at least about 50°C.