PRODUCTION OF A GRANULAR ENZYME PRODUCT AND ITS USE IN DETERGENT COMPOSITIONS

Abstract: The granulate detergent enzyme product produced according to the invention comprises a core of a microbial enzyme containing material with an enteric coating. Due to the coating the enzymatic stability is enhanced, in the presence of other detergent components, especially strong bleaching agents. The coating is carried out in a fluid bed in which an aqueous dispersion of the coating agent is introduced. Also coatings with antioxidants and acid coatings enhance the enzymatic stability.

Description: TECHNICAL FIELD The technical field to which this invention pertains comprises a method for production of a granulate detergent enzyme product comprising a core of a microbial enzyme containing material and a coating. BACKGROUND ART The field of enzymatic detergent additives has been rapidly growing during the last decades. Reference is made to e.g. the article "How Enzymes Got into Detergents", vol. 12, Developments in Industrial Microbiology, a publication of the Society for Industrial Microbiology, American Institute of Biological Sciences, Washington, D.C. 1971, by Claus Dambmann, Poul Holm, Villy Jensen and Mogens Hilmer Nielsen, to the article "Production of Microbial Enzymes", Microbial Technology, Sec. ed., Vol. I, Academic Press, 1979, pages 281 - 311, by Knud Aunstrup, Otto Andresen, Edvard A. Falch and Tage Kjaer Nielsen, and to P.N. Christensen, K. Thomsen and S. Branner: "Development of Detergent Enzymes", a paper presented on 9 October 1986 at the 2nd World Conference on Detergents held in Montreux, Switzerland. The most common enzymatic detergent additive is a proteolytic additive, but also amylolytic, cellulolytic, and lipolytic detergent additives are described, e.g. in GB patent No. 1 554 482, BE patent No. 888 632, and US patent No. 4,011,169, column 4, line 65 to column 5, line 68. The above list of enzymes is not exhaustive, but represents the most common enzymatic additives used in detergents. Enzymatic detergent additives for use in powder detergents are usually prepared in the form of dust-free granulates. These granulates can be produced in several different ways. Reference can be made to GB patent No. 1 362 365 which describes the production of enzyme containing granulates used as detergent additives by means of an apparatus comprising an extruder and a spheronizer (sold as MARUMERIZER®), and to US patent No. 4 106 991, which describes the production of enzyme containing granulates used as detergent additives by means of a drum granulator. Reference is also made to European patent publication EP-A-0170360 which describes enzyme granulates containing certain salts to improve the storage stability. Whereas enzyme granulates prepared according to known methods are entirely satisfactory for use in many commercial powder detergents, we have recognized that enzyme stability of these granulates is reduced in certain detergent formulations and at certain storage conditions. These include particularly detergents with high water content and/or high pH and/or high content of bleaching agents and particularly storage at high humidity and temperature. In FR patent No. 2.058.421 a method for production of detergent or bleaching agents containing enzymes protected with a coating of an enteric coating agent is described. However, the applicant has shown that the coating effect, i.e. the improvement of enzymatic stability, is absent, very small or even negative, probably due to the fact that the particle size of the powder is too small in comparison to the small amount of coating agent used, and that the coating agent is not coated on the powder in an optimal manner. Also, this method involves the use of a solution of the coating agent in an organic solvent. Thus, we have recognized that a need exists for an easier and more efficient method for production of a particulate detergent enzyme product which is modified in such manner that the enzymatic stability is improves considerably in adverse detergent formulations and/or at adverse storage conditions, whereby this modification in no regard should impair any process or material related to the continued storage and later use of the product. After considerable research, on new additives and/or coatings, and application techniques for such coatings we have surprisingly discovered that a coating of the particulate detergent enzyme with only one specified category of coating agents, out of many possibilities, combined with a specific coating technique will modify the particulate detergent enzyme in the wanted manner, i.e. this coating will improve the enzymatic stability at adverse conditions, without any accompanying unwanted side effects. Thus, the method according to the invention for production of a granulate detergent enzyme product comprising a core of a microbial enzyme containing material and a coating of an enteric coating agent thereon, whereby the weight of the enteric coating agent is between 1 and 40% of the weight of the product, preferably between 1 and 5% of the weight of the product, is characterized by the fact that the cores of the microbial enzyme containing material and an aqueous dispersion of the coating agent are introduced into a fluid bed drying apparatus, whereafter the material leaving the apparatus is collected as the product. It is an important advantage that it is unnecessary to use any organic solvents during the production; if, however, the use of organic solvents for some reason should be desired, organic solvents can be used as well. The fluid bed method can be carried out batchwise or continuously. Any fluid bed method can be used in the method according to the invention, e.g. a usual fluid bed process, a Wurster bed process or a rotor bed (Glatt) process (vide e.g. David M. Jones, "Factors to consider in fluid-bed processing", Pharmaceutical Technology, April 1985). However, any other process than a fluid bed process by means of which a satisfactory coating can be applied on a particulate material without unwanted agglomeration due to adhesion between particles, is considered a technical equivalent and can be used, e.g. a coating pan process or a coating process in a mixer (e.g. a Lödige mixer) can be used for manufacture of the product according to the invention. If more than one coating is to be applied to the particulate material, each individual coating can be applied by any usable coating method. In this specification with claims the detergent concept is to be understood in a broad sense. Thus, the term granulate detergent enzyme product is intended to include any granulate enzyme product which is a part of or is intended later to be a part of any cleaning or cleansing composition, e.g. a bleaching agent, a softener, a color clarification agent or a pure surfactant. Further, the detergent according to the invention comprises any cleaning or cleansing composition containing the product according to the invention, and the detergent component according to the invention comprises for instance a bleaching agent, a softener, a color clarification agent or a pure surfactant containing the product according to the invention. The invention is only concerned with microbially produced enzymes, as other enzymes are not suited as enzymatic detergent additives, mainly due to cost and stability considerations. In the pharmaceutical art an enteric coating is a well defined material, i.e. a special coating applied to tablets or capsules which prevents release and absorption of their contents until they reach the intestines. For a description of a typical enteric coating agent reference can be made to e.g. Manufacturing Chemist, August 1986, p. 35-37. It is to be understood that most, maybe all enteric coating agents which can be used in the pharmaceutical field, can be used in the invention as well. Typical examples of enteric coating agents are: cellulose acetate phthalate (Cellacephate®, CAP), vinyl acetate crotonic acid copolymer (Luviset®), methacrylic acid, (meth)acrylic acid ester copolymer (Eudragito®), hydroxypropyl methylcellulose phthalate. Due to the nature of an enteric coating the particulate detergent enzyme product according to the invention exhibits most favorable stability enhancing characteristics in an acid environment, e.g. when mixed with a powerful acid bleaching agent. Such powerful acid bleaching agents are described e.g. in Fette Seifen Anstrichmittel 88′ Jahrgang, Nr. 5, 1986, 159-165, and GB patent no. 2,135,347 A. According to US home laundering practice powerful acid bleaching agents are added separately from the detergent to the washing machine, i.e. are not previously mixed with the other alkaline detergent components. Thus, the particulate detergent enzyme produced according to the invention may be mixed with such acid bleaching agents. If the particulate detergent enzyme product is added to other detergent components of an alkaline nature, the stability enchancing effect may be lowered, due to the solubility of the enteric coating at high pH-values. However, in such instances special precautions for keeping stability at a high level may be taken, as is explained later in more detail. The enteric coating agent does not generate any disturbing influence during the washing process, as it will dissolve in the washing liquid (which typically are of a pH value at which the enteric coating agent is easily soluble) whereafter the enzyme can exert its wanted activity on the laundry. Also, especially in a damp atmosphere and at relatively high temperatures it has been found that the enzymatic stability is satisfactory during storage of the product according to the invention in the presence of powerful bleaching agents. In Acta Pharmaceutica Technologica 31 (1) 1985, p. 38-41 non-enteric and enteric film coating of commercial pancreatin tablets is described. From Fig. 2 (B) of this paper it appears that the enzyme stability of the non coated tablets and the tablets coated with Eudragit® L are equal, suggesting to a skilled worker in the art that Eudragit® L is not an advantageous coating agent for pancreatin tablets in the pharmaceutical field. GB patent No. 1 294 557 discloses a method for production of microcapsules containing a detergent enzyme during which a binder, which can be a copolymer of acrylic acid, is used. However, in the known process microcapsules comprising a homogeneous mixture of soluble, inorganic salt, binder and enzyme, are produced, rather than the enzyme containing particles coated with a coating which is specified both in regard to composition and permeability according to the invention. Also, the known microcapsules do not offer the technical advantage exhibited by the product produced according to the invention. In Japanese patent publication No. JP-60-190,497A a method for production of an enzymatic detergent composition is described during which a copolymer containing aliphatic unsaturated dicarboxylic acid monomer in an aqueous medium is used. However in contradistinction to the present invention no impermeable coating for protection of the detergent enzyme is suggested. In a preferred embodiment of the method according to the invention more than 90% of the enzyme granulate cores exhibit particle sizes between 2 and 2000 µm. This particle size range is most useful for a granulate detergent enzyme product. In a preferred embodiment of the method according to the invention more than 90% of the granulate cores exhibit particle sizes between 2 and 100 µm. This size range of granulate is specially suited as a constituent in a suspension containing this granulate and a strong bleaching agent. In a preferred embodiment of the method according to the invention more than 90% of the granulate cores exhibit particle sizes between 250 and 1000 µm. This size range of granulate is specially well suited as a constituent in a granulate detergent formulation comprising a bleaching agent and alkaline detergent components. In a preferred embodiment of the method according to the invention the weight of the coating agent applied to the granulation core is between 10 and 30% of the weight of the coated product. If the weight of coating agent is less than 10% the satisfactory stabilizing effect is not obtained, and with a weight of coating agent above 30% only a little improvement in stability is obtained. In a preferred embodiment of the method according to the invention the weight of the coating agent is between 5 and 20% of the weight of the product. A product with this coating is especially well suited for particles with relatively small particles or particles containing more sensitive enzymes. In a preferred embodiment of the method according to the invention the enteric coating agent is a copolymer of a (meth)acrylic acid or derivative thereof and another (meth)acrylic acid or derivative thereof. It goes without saying that only copolymers with film forming characteristics can be used, e.g. copolymers with a molecular weight above around 100,000 beyond which molecular weight most properties do not change with the exception of viscosity (in solution). Copolymers of this type is sold under the trade mark Eudragit® (Röhm Pharma, GmbH, Darmstadt, Postfach 4347, West Germany) and it has been found that the Eudragit® copolymer is able to form an impermeable enteric coating. In a preferred embodiment of the method according to the invention the copolymer is a copolymer of methacrylic acid and an acrylic acid ester, preferably a methyl or ethyl ester. Such a product is commercially available under the trade mark Eudragit® L 30 D. This enteric coating agent can be applied as an aqueous emulsion in a fluid bed coating process, and thus the use of organic solvents can be avoided. In a preferred embodiment of the method according to the invention the copolymer is a copolymer of methacrylic acid and methacrylic acid methyl ester. Such a product is commercially available under the trade mark Eudragit® L/S. This enteric coating agent can be applied as an organic solution in a fluid bed process, and a coating with a high permeability is thereby obtained. In a preferred embodiment of the method according to the invention the coating agent contains between 25 and 100% of the enteric coating agent (on a dry substance basis). If the coating agent contains less than 25% of the enteric coating agent, the impermeability of the coating is not satisfactory. In a preferred embodiment of the method according to the invention the part of the coating agent which is not the enteric coating agent is a filler, preferably CaCO₃, talc and/or TiO₂, and/or a plasticizer, preferably PEG and/or PVP. The filler may be added for economic and/or cosmetic purposes, and the plasticizer can be added to improve the flexibility of the coating. The coating agent can consist of enteric coating agent entirely, though, and also, other additives than fillers and plasticizers may be present in the coating agent. In a preferred embodiment of the method according to the invention the enzyme is one or more of a protease, an amylase, a lipase, a cellulase, and an oxidase. These are the most commonly used detergent enzymes. Practice of the invention applies to any detergent enzyme. In a preferred embodiment of the method according to the invention the particles of enzyme containing material are commercially available granulates. Usually these granulates are already coated but their coating does not generate a satisfactory enzyme stability in the presence of powerful bleaching agents. Such particles are easily available and are well suited for the invention. In a preferred embodiment of the method according to the invention the particles already possess or are given a coating containing or consisting of an antioxidant, preferably as an undercoat to the enteric coating. This embodiment is specially well suited in such cases in which the granulate detergent enzyme product is mixed with a powerful bleaching agent. In that case small amounts of humidity saturated with bleaching agent may diffuse into the enzyme granules, even through the enteric coating, and impair the stability of the enzyme. In this embodiment, however, the antioxidant in the undercoat will react with the bleaching agent and thus improve the enzyme stability. In a preferred embodiment of the method according to the invention the particles possess a coating containing or consisting of an acid material, preferably as an overcoat on the enteric coating. This embodiment is specially well suited, when it is intended to mix the product according to the invention with alkaline detergent components. In such instances the solubilizing capability of the alkaline detergent components on the enteric coating is inhibited, and thus, the stability of the product according to the invention will be enhanced. In a preferred embodiment of the method according to the invention any two of the three coatings or all three coatings are united to one single, combined coating. This is an advantage from a production point of view. Also, the invention comprises a use of the granulate detergent enzyme product prepared according to the invention as a constituent of a detergent or of a detergent component. In a preferred embodiment of the use according to the invention the product exhibits a particle size interval characterized by the fact that 90% of the granulate cores exhibit particle sizes between 2 and 100 µm, and the detergent or the detergent component appear as a slurry. In this manner a physically stable mixture can easily be obtained by addition of sedimentation inhibition agents. In a preferred embodiment of the use according to the invention the product exhibits a particle size interval characterized by the fact that 90% of the granulate cores exhibit particle sizes between 250 and 1000 µm, and the detergent or the detergent component appear as a particulate material. In this manner it is possible to obtain a mixture, the homogeneity of which does not change with time. In a preferred embodiment of the use according to the invention the product exhibits a particle size interval characterized by the fact that 90% of the granulate cores exhibit particle sizes between 250 and 1000 µm, the detergent component appear as a particulate material, and the detergent component is an acid bleaching agent. It has been found that the stability of the product is satisfactory even in the presence of powerful acid bleaching agents. Finally the invention comprises a detergent or a detergent component, containing as a constituent the product prepared according to the invention. In a preferred embodiment of the detergent or detergent component according to the invention the product exhibits a particle size interval characterized by the fact that 90% of the granulate cores exhibit particle sizes between 2 and 100 µm, and the detergent or the detergent component appear as a slurry. In this manner a physically stable mixture can easily be obtained by addition of sedimentation inhibition agents. In a preferred embodiment of the detergent or detergent component according to the invention the product exhibits a particle size interval characterized by the fact that 90% of the granulate cores exhibit particle sizes between 250 and 1000 µm, and the detergent or the detergent component appear as a non dusting granulate. In this manner it is possible to obtain a mixture, the homogeneity of which does not change with time. In a preferred embodiment of the detergent or detergent component according to the invention the product exhibits a particle size interval characterized by the fact that 90% of the granulate cores exhibit particle sizes between 250 and 1000 µm, the detergent component appear as a particulate material, and the detergent component is an acid bleaching agent. It has been found that the stability of the product is satisfactory even in the presence of powerful acid bleaching agents. The invention will be illustrated by means of the following examples. MODES FOR CARRYING OUT THE INVENTION, INCLUDING BEST MODE EXAMPLE 1 The following enzyme containing products used as starting materials will appear in this example. These four enzyme products are commercially available granulates; they were used as controls and as starting materials for production of the products prepared according to the invention. On the basis of the starting materials 2 and 4 products were produced according to the invention in the following manner. 2 or 4 were introduced into a fluid bed drying apparatus with 15 kg/charge, and simultaneously a 30% aqueous dispersion of Eudragit® L 30 D was introduced at a rate of 4.5 kg/hour together with inlet air of a temperature of 60°C to yield a product consisting of the starting material coated with 9% Eudragit® L 30 D. The corresponding two products according to the invention are designated 2i and 4i. The six products 1, 2, 3 and 4 (prior art products) and 2i and 4i (products prepared according to the invention) were mixed with a detergent containing around 4% of an acid bleaching agent in a proportion of 1% w/w. The mixtures are designated Ml, M2, M2i, M3, M4, and M4i. Storage stability tests on the six mixtures were carried out both in vessels with controlled humidity and in closed vessels (dry). The results are tabulated below. The stability tests clearly show that the coating of the product prepared according to the invention exerts the stability improving effect only in the presence of humidity, when mixed with a powerful oxidizing agent. In a dry atmosphere the stability is satisfactory already in the absence of the coating on the product prepared according to the invention. EXAMPLE 2 The formulation of the raw granulate, i.e. the totally unprotected granulate core, is as follows: 15% of fibrous cellulose 9% of carbohydrate binder 4% of TiO₂ ad 100% of Na₂SO₄/ALCALASE® concentrate ALCALASE® (Novo Industri A/S) is a Bacillus licheniformis proteinase. This raw granulate is produced in such enzyme strength which after the coating will generate a final proteolytic activity of 2.0 Anson units/g. Except for differences in composition the production of the raw granulate is carried out as described in US patent no. 4.106.991, example I. The primary coating of the raw granulate is carried out as indicated in US patent no. 4.106.991, example XXII and consists of 7% PEG 4000 and 9% TiO₂, the percentages being calculated in relation to the weight of the raw granulate. This product is designated ALCALASE® T 2.0. The process parameters in relation to the application of the three coatings indicated in the following (in relation to e.g. temperatures, spray pressure and spray rate) and of the coatings in the following examples were as indicated in the section "Processing Date" in the pamphlet Eudragit® L, Technical application Pamphlet (info LD-12/e) from Röhm Pharma GmbH, Weiterstadt, Germany. Almost all coatings are applied in a fluid bed of the type Glatt WSG 5. 6 kg of ALCALASE® T 2.0 is transferred to the fluid bed, and an antioxidant suspension/solution with the composition given below is applied with simultaneous drying: 480 g of sodium bisulfite 480 g of talc 120 g of TiO₂ 240 g of carbohydrate binder 1500 g of water The above components form a coherent layer on the surface of the granules of ALCALASE® T 2.0. After a short intermediate drying the next (enteric) coating is applied. 2.0 kg of a 30% aqueous emulsion of Eudragit® L 30 D is sprayed onto the particles. During the process minor samples corresponding to 1.25, 2.5, and 5% by weight of Eudragit® L 30 D are taken out for later stability testing purposes. The process is interrupted when the coating with Eudragit® L 30 D amounts to 10%. Then the (acid) top coating is applied by means of an aqueous solution consisting of 120 g of citric acid 60 g of talc 30 g of hydroxypropyl cellulose (Klucel E) 600 g of water Now the storage stability of the final product and of the intermediate products are tested in the presence of an acid bleaching agent. The testing conditions were as follows: 1% granulate and 99% acid bleaching composition. 30°C, 60/80% relative humidity (alternating as 60% r.h. for 8 hours, and 80% r.h. for 16 hours, etc.), open vessels. It clearly appears from the above table that all coatings prepared according to the invention do exhibit a significant stabilizing effect. EXAMPLE 3 The reference composition is ALCALASE® T 2.0 as in Example 2. As in Example 2 the reference is coated with an antioxidant coating and with an enteric coating. Also, a reference composition similar to ALCALASE® T 2.0 based on NaCl instead of Na₂SO₄ was prepared and designated ALCALASE® T 2.0 NaCl. ALCALASE® T 2.0 NaCl was coated with an antioxidant, and also with an antioxidant and an enteric coating, and furthermore with an antioxidant, an enteric coating, and an acid coating. All enteric coatings were performed with Eudragit® L 30 D. The storage stability was measured in the same manner as indicated in Example 2. The results appear from the following table. The clear stability enhancing effect of both the antioxidant and the enteric coating appears from the above table. EXAMPLE 4 6 kg of ALCALASE® T 2.0 is transferred to the fluid bed, and a suspension/solution with the composition given below is applied with simultaneous drying: 240 g of TiO₂ 240 g of talc 240 g of NaHSO₃ 160 g of carbohydrate binder 1000 g of water A similar coated product, in which NaHSO₃ in the coating fluid is substituted by Na₂SO₃, is produced. These products are coated with 10% Eudragit® L 30 D, as in Example 2, and were tested as described in Example 2. The storage stability was measured in the same manner as indicated in Example 2. The results appear from the following table 4. The above table clearly demonstrates the effect on the storage stability originating from the antioxidant. EXAMPLE 5 The reference composition in this Example is ALCALASE® T 2.0. This reference is coated with antioxidant and/or enteric coating, basically in the same manner as indicated in Example 2, and the thus coated products are evaluated for storage stability of the enzyme. The antioxidant coating is carried out as follows: 8 kg of ALCALASE® T 2.0 is coated in a Lödige mixer (type FM 50) with a mixture of 3,5 kg of talc 3,5 kg of finely milled Na₂SO₄ 0,5 kg of TiO₂ which is bound to the surface of the granulate by means of a binder solution consisting of 400 g of carbohydrate binder 200 g of NaHSO₃ 1600 g of water Powder and binder solution is applied to the granulate in such manner that primarily a fifth of the powder is bound to the surface of the granulate with a fifth of the binder solution, whereafter the next fifth of the powder and the binder solution is applied, and so on. Finally the coated granulate is transferred to a spheronizer (Marumerizer®), in which the surface is compacted and smoothed. Finally the granulate is dried in a fluid bed. In a similar manner a granulate is produced with sodium ascorbate as antioxidant, NaHS03 in the binder solution being exchanged with sodium ascorbate. A portion of the two antioxidant coated granulates are coated with Eudragit® L 30 D in a fluid bed to the extent of 5 and 10% by weight. The storage stability was measured in the same manner as indicated in Example 2. The results appear from the following table. EXAMPLE 6 The reference in this example is ALCALASE® T 2.0 (sulfate based). In a Glatt WSG flud bed coatings of Eudragit® L 30 D corresponding to 10, 20, 30, and 40%, respectively, were applied to the ALCALASE® T 2.0 granulate. The storage stability was measured in the same manner as indicated in Example 2. The results appear from the following table. EXAMPLE 7 6 kg of ALCALASE T 2.0 is transferred to a fluid bed, and a suspension/solution with the following composition is applied with simultaneous drying: 230 g of antioxidant 120 g of TiO₂ 480 g of talc 240 g of carbohydrate binder 1500 g of water The antioxidant is either NaHSO₃ or Na₂SO₃ or a mixture thereof (126 g Na₂SO₃/104 g NaHS0₃). The so obtained products are coated with 2.5 and 5.0% of Eudragit L 30 D, respectively, as described in Example 2. The shelf stability of the products is compared to the shelf stability of ALCALASE® T 2.0 without a protective coating and of ALCALASE® T 2.0 coated solely with 2.5 and 5.0% of Eudragit® L 30 D, respectively, i.e. without any antioxidant. The testing conditions were as follows: 1% granulate and 99% acid bleaching composition, 30°C, 60/80% relative humidity, open vessels, i.e. as in Example 2.

Claims: 1. Method for production of a granulate detergent enzyme product comprising a core of a microbial enzyme containing material and a coating of an enteric coating agent thereon, whereby the weight of the enteric coating agent is between 1 and 40% of the weight of the product, preferably between 1 and 5% of the weight of the product, characterized by the fact that the cores of the microbial enzyme containing material and an aqueous dispersion of the coating agent are introduced into a fluid bed drying apparatus, whereafter the material leaving the apparatus is collected as the product. 2. Use of the granulate detergent enzyme product prepared according to Claim 1 as a constituent of a detergent or a detergent component. 3. Use according to Claim 2, wherein the product exhibits a particle size interval corresponding to the fact that more than 90% of the enzyme granulate cores exhibit particle sizes between 2 and 100 µm, and wherein the detergent or the detergent component appear as a slurry. 4. Use according to Claim 2, wherein the product exhibits a particle size interval corresponding to the fact that more than 90% of the enzyme granulate cores exhibit particle sizes between 250 and 1000 µm, and wherein the detergent or the detergent component appear as a particulate material. 5. Use according to Claim 2, wherein the detergent component is an acid bleaching agent. 6. Detergent or detergent component, containing as a constituent the product prepared according to Claim 1. 7. Detergent or detergent component according to Claim 6, wherein the product exhibits a particle size interval corresponding to the fact that more than 90% of the enzyme granulate cores exhibit particle sizes between 2 and 100 µm, and wherein the detergent or the detergent component appear as a slurry. 8. Detergent or detergent component according to Claim 6, wherein the product exhibits a particle size interval corresponding to the fact that more than 90% of the enzyme granulate cores exhibit particle sizes between 250 and 1000 µm, and wherein the detergent or the detergent component appear as a particulate material. 9. Detergent component according to Claim 8, wherein the detergent component is an acid bleaching agent.

Inventors: FALHOLT, PER
Applicants: NOVO-NORDISK A/S
Application year: 1987
Main classification: C11D3
IPC codes: C11D3, C11D7, C11D17, C12N9