Patent Publication Number: US-2020299669-A1

Title: Processes for the Manufacture and Use of Pancreatin

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/703,813 filed Jul. 29, 2005, which is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     Described herein is a process for the manufacture and use of pancreatin in which the concentration of one or more viral contaminants therein is reduced by heating the pancreatin. 
     BACKGROUND 
     Pancreatin is a substance which is derived from mammalian pancreas glands and comprises different digestive enzymes such as lipases, amylases and proteases. Pancreatin has been used to treat pancreatic exocrine insufficiency which is often associated with cystic fibrosis, chronic pancreatitis, post-pancreatectomy, post-gastrointestinal bypass surgery (e.g. Billroth II gastroenterostomy) and ductal obstruction from neoplasm (e.g. of the pancreas or common bile duct). For the application of pancreatin in pharmacological products it is preferred to substantially maintain the intrinsic high level of activity of the different digestive enzymes. However, these enzymes can be subject to degradation, e.g., upon storage, and are particularly sensitive to elevated temperatures. Thus, pancreatin requires carefully controlled conditions during the overall handling, manufacturing and storage process. 
     Due to the animal origin of pancreatin, this may further comprise other components which are unwanted such as one or more biological contaminants. During more than 100 years of commercialization of pharmaceutical products containing pancreatin, no case has been reported where patients have been affected by pancreatin contaminated by any virus. However, companies producing pharmaceutical products derived from biological tissues and/or body fluids experience increasing pressure from the regulatory bodies to increase the level of safety of their products by reducing all kinds of contaminants to the lowest level possible, independent of whether any concerned contaminant is considered a human pathogen or not. For the application of pancreatin in pharmacological products, it is therefore desirable to minimize the concentration of biological contaminants therein down to generally accepted detection limits. 
     Hence, for the manufacturing, handling and storage process of pancreatin, the skilled person is faced with the challenge of tailoring such processes in a way that a high level of activity of the different digestive enzymes is maintained while at the same time the concentration of one or more biological contaminants therein is minimized. 
     The current manufacturing processes of pancreatin would not seem to allow efficient inactivation of biological contaminants, in particular of specific viruses. 
     Different approaches are known to reduce the concentrations of viruses and bacteria within enzymatic compositions. Such methods include heat treatment, filtration, the addition of chemical inactivants or sensitizers, treatment with irradiation and extended heating. These methods are described below. 
     Heat treatment implies that the product e.g. be heated to 60° C. for 70 hours which can be damaging to sensitive products. In some instances, conventional heat inactivation can actually destroy a substantial amount of the enzymatic activity of a product. 
     Filtration involves filtering the product in order to physically remove contaminants. Unfortunately, this method may also remove products having a high molecular weight. Further, in certain cases, small viruses and similarly sized contaminants and pathogens may not be removed by the filter. 
     The procedure of chemical sensitization involves the addition of noxious agents which bind to the DNA/RNA of the virus and which are activated by either UV or other radiation. The radiation produces reactive intermediates and/or free radicals which bind to the DNA/RNA of the virus, break the chemical bonds in the backbone of the DNA/RNA, and/or crosslink or complex it in such a way that the virus can no longer replicate. This procedure requires unbound sensitizer to be washed from products since the sensitizers are toxic, if not mutagenic or carcinogenic, and cannot be administered to a patient. 
     U.S. Pat. No. 3,956,483 (Lewis) discloses a method of preparing pancreatin having suitable amylolytic, proteolytic and lipolytic activities and of eliminating harmful bacteria therefrom while maintaining said activities. Said method comprises heating the pancreatin to a sufficiently high temperature between 120° F. and 180° F. (approx. 49-82° C.). Lewis, however, fails to provide a process which would be suitable to minimize the concentration of viruses down to presently accepted detection limits. 
     U.S. Pat. No. 6,749,851 (Mann) suggests the treatment of compositions comprising digestive enzymes by stabilizing the compositions in a first step by either (a) reducing the temperature of, (b) reducing the solvents of, or (c) adding a stabilizer to the composition, followed by irradiation of the composition in a second step. 
     Braeuniger et al. (Braeuniger et al., Int. J. Hyg. Environ. Health 203, 71-75, 2000) suggest the use of heat for the inactivation of the bovine parvovirus. It has been demonstrated that the bovine parvovirus which can be deactivated is dependent upon exposure and residual moisture. In general, higher moisture contents allow shorter heat exposure durations providing the same inactivation as a lower moisture content in combination with a longer exposure duration. However, Braeuniger et al. do not disclose anything about the effect that heat has on enzymes such as lipases, amylases and proteases forming part of animal pancreatin. Thus, there is a need for a process which provides pancreatin having enzymes with a high level of activity while sufficiently reducing the concentration of biological contaminants. 
     It has now been found that select conditions can be employed in the manufacture of pancreatin in which the concentration of one or more biological contaminants therein has been reduced and in which the enzyme activity is maintained at an acceptable level. In particular, it has been found that a process as disclosed and claimed herein is useful to decrease the concentration of viral contaminants in pancreatin. Furthermore, the process described herein has been found to effectively meet various regulatory requirements regarding the removal of viruses from biological products (e.g. “Note For Guidance on Virus Validation Studies: The Design, Contribution and Interpretation of Studies Validating the Inactivation and Removal of Viruses”, issued from the Committee For Proprietary Medicinal Products (herein after referred to as “CPMP/BWP/268/95”)) while at the same time maintaining enzyme activities (e.g. lipase, protease and amylase) at an acceptable level. 
     Another advantage of the process described herein, and the resulting pancreatin, as well as the pharmaceutical compositions comprising the pancreatin obtained by the process described herein, is its applicability for laboratory scale, pilot scale and production scale. 
     SUMMARY 
     Accordingly, one embodiment disclosed herein is a process for the manufacture of pancreatin in which the concentration of one or more biological contaminants, in particular of viral contaminants, has been reduced by heating the pancreatin for a period up to about 48 hours at a temperature of at least 85° C. wherein the solvents in the pancreatin are less than about 9% by weight at any point during the heating step. Such process provides pancreatin, in which the enzyme activity is maintained at an acceptable level and in which the concentrations of one or more biological contaminants, in particular of one or more viral contaminants, are reduced. Described herein is a process for the manufacture of pancreatin, comprising heating a dispersed form of pancreatin containing one or more solvents at a temperature of at least 85° C. for a period of up to about 48 hours, and wherein the total amount of solvents present in the pancreatin is less than about 9% by weight at any point during the heating step. 
     Another embodiment disclosed herein is a process for manufacturing a pharmaceutical composition comprising pancreatin, in accordance with the disclosed process wherein such pharmaceutical composition is in a dosage form suitable for oral administration and for immediate and/or modified release, such dosage form can be selected from tablets, microtablets, pellets, micropellets, microspheres, granules, granulates, powders, suspensions, emulsions, dispersions, capsules, sachets as well as other dosage forms. 
     Another embodiment is a pharmaceutical composition comprising
         (1) a pharmacologically effective quantity of pancreatin wherein said pancreatin has been heated in the form of a dispersed pancreatin containing one or more solvents, wherein the total amount of solvents present in the pancreatin is less than about 9% by weight at any point during the heating step, to a temperature of at least 85° C.; wherein the titer level of a viral contaminant present in the pancreatin after heating is at least about 1000 times less than the titer level of the viral contaminant present in the pancreatin prior to heating; and   (2) one or more pharmaceutically acceptable excipients.       

     Another embodiment is directed to a pharmaceutical composition in the form of a capsule or sachet wherein the capsule or sachet comprises pancreatin subjected to the disclosed process. 
     Another embodiment is directed towards a method of treating pancreatic exocrine insufficiency by administering a safe and effective amount of pancreatin obtained by the process described herein. 
     Other objects, features and advantages will be set forth in the detailed description of embodiments that follows, and in part will be apparent from the description or may be learned by practice of the claimed invention. These objects and advantages will be realized and attained by the processes and compositions particularly pointed out in the written description and claims hereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1 : Lipase activity after heating pancreatin at temperatures of 80° C., 85° C., 90° C., 95° C. and 100° C. with a solvent content of 1%. The lipase activity was determined after 2, 4, 6, 12, 15, 18, 21, 24 and 30 hours. 
         FIG. 2 : Lipase activity after heating pancreatin at temperatures of 90° C. and 95° C. with a solvents content of 3%. The lipase activity was determined after 2, 4, 8, 15, 24 and 48 hours. 
         FIG. 3 : Lipase activity after heating pancreatin at a temperature of 80° C. having a solvent content of 3%, 6%, 9% and 12%. The lipase activity was determined after 0.5, 1.0 and 3.0 hours. 
         FIG. 4 : Log titer reduction of porcine pancreatin spiked with porcine parvovirus (hereinafter referred to as “PPV-spiked pancreatin”) at temperatures of 80° C., 85° C., 90° C., 95° C. and 100° C. having a solvent content of 1%. The virus concentration was determined after 6, 12, 15, 18, 21, 24 and 30 hours. 
         FIG. 5 : Log titer reduction of PPV-spiked pancreatin at temperatures of 90° C. and 95° C. having a solvent content of 1% and 3% for a period of 12 hours. The virus concentration was determined after 3, 6 and 12 hours. 
     
    
    
     DETAILED DESCRIPTION 
     Unless defined otherwise, all technical and scientific terms used herein are intended to have the same meaning as is commonly understood by one of ordinary skill in the relevant art. 
     As used herein, the term “sterilize” is intended to mean a reduction in the concentration of at least one biological contaminant found in pancreatin, in particular dispersed pancreatin, being subjected to the process described herein. More specifically, the term “sterilize” is intended to mean a reduction in the concentration of at least one viral contaminant found in pancreatin, in particular dispersed pancreatin, being subjected to the process described herein. 
     As used herein, the term “pancreatin” is intended to mean pancreatin originating from any mammalian pancreas glands, such as bovine and porcine pancreatins. For example, pancreatin which is produced according to the processes described in U.S. Pat. No. 4,623,624 or according to analogous processes may be used for the purposes of the present disclosure. To achieve the preferred results of decreasing the biological contaminants in the pancreatin, the use of a dispersed form of pancreatin which is compatible with the process conditions described herein is preferred. Dispersed forms of pancreatin comprise e.g. powders, pellets, micropellets, microspheres, granules and granulates. Preferred results are achieved with pancreatin powders, e.g. pancreatin powders directly obtained from a process to produce pancreatin. The pancreatin as used herein may also comprise one or more pharmaceutically acceptable excipients which are compatible with the process conditions as described herein and which may be e.g. selected from the pharmaceutically acceptable excipients provided below. 
     As used herein, the term “biological contaminant(s)” is intended to mean a contaminant that, upon direct or indirect contact with pancreatin, may have a deleterious effect on the pancreatin or upon a recipient thereof. Furthermore, the term “active biological contaminant” is intended to mean a biological contaminant that is capable of causing a deleterious effect, either alone or in combination with another factor, such as a second biological contaminant, in the preparation of pancreatin or to the recipient of the pancreatin. Such biological contaminants include, but are not limited to, viral contaminants and/or germs. Germs include, but are not limited to, bacteria, molds and/or yeasts. A biological contaminant may be a human pathogen. 
     As used herein, the term “virus” or “viral contaminant(s)” is intended to mean particularly non-enveloped viruses. More specifically, the term “virus” or “viral contaminant(s)” includes so-called highly resistant viruses like the parvoviridae, in particular the porcine parvoviridae, the circoviridae, in particular the porcine circoviridae, and the caliciviridae, in particular the porcine caliciviridae. The porcine parvovirus (PPV) may serve as a generally accepted model or indicator virus for the whole class of highly resistant viruses, in particular highly resistant porcine viruses. Furthermore, the term “virus” or “viral contaminant(s)” in the context of the present disclosure also includes the picornaviridae, in particular the porcine picornaviridae, the reoviridae, in particular the porcine reoviridae, the astroviridae, in particular the porcine astroviridae the adenoviridae, in particular the porcine adenoviridae and the hepeviridae, in particular the porcine hepeviridae. 
     As used herein, the term “solvent” or “solvents” is intended to mean the amount or proportion of liqiud which is present in the pancreatin, either as bound or complexed liquid or as freely available liquid in the pancreatin. Freely available liquid means the liquid present in the pancreatin being heated that is not bound to or not complexed with the pancreatin. Said liquids present in the pancreatin usually comprise water and enzyme friendly organic solvents and mixtures of water with said enzyme friendly organic solvents. Suitable enzyme friendly organic solvents are usually volatile organic solvents like e.g. acetone, chloroform, dichloromethane or straight-chained or branched C 1-4 -alcanols, particularly methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, tert.-butanol or mixtures of said solvents. 2-propanol is preferred as enzyme friendly organic solvent. Typically, the ratio of water to enzyme friendly organic solvent is between 50:1 and 3:1, more typically between 30:1 and 10:1. 
     Whenever a temperature range, e.g. of from 85° C. to about 100° C., is used, it is intended to mean a temperature anywhere within the expressly mentioned range as well as a temperature profile leading to different temperatures within the expressly mentioned range. The temperature range during the process as disclosed herein can be applied continuously or discontinuously, as long as the overall periods of time within the disclosed temperature ranges are met. 
     The process described herein comprises heating the pancreatin for a period up to about 48 hours at a temperature of at least 85° C. wherein the total amount of solvents present in the pancreatin is less than about 9% by weight at any point during the heating step. 
     In one embodiment of such a process, the solvents content of the pancreatin is typically less than about 8%, even more typically less than about 6%, usually less than about 5%, mostly less than about 3.5%, preferably from about 0.1% to about 3.5%, more preferably from about 0.1% to about 3% and even more preferably from about 0.1% to about 1.6% by weight. In other embodiments, the solvent content is less than about 7.5%, 7.0%, 6.5%, 6.0%, 5.5%, 5.0%, 4.5%, 4.0%, 3.5%, 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, or 0.5%. 
     In one embodiment, the process described herein uses a dispersed pancreatin, in particular a pancreatin powder, with an initial solvents content of about 9% by weight or less, typically between about 2% and about 3.5% by weight. The pancreatin is then heated to the desired process temperature which may be from 85° C. to about 100° C., e.g. 90° C. During the initial heat-up phase, the solvents content in the pancreatin will typically decrease as a function of time and temperature. It is to be understood that the duration of said initial heat-up phase is a function of batch-size and initial batch temperature and therefore may take between approximately 15 minutes and as long as about 10 hours. After the heat-up phase, the pancreatin is heated at a temperature of at least 85° C., usually within the range of 85° C. to about 100° C., e.g. about 90° C., and for the disclosed process time, i.e. for a period of up to about 48 hours, e.g. for a period of 24 hours. When using the process within the parameters disclosed herein (typically under atmospheric pressure), the solvents content reached at the end of the heat-up phase can typically be found to be from about 0.1% to about 1.6% by weight. It can be observed that the solvents content of about 0.1% to about 1.6% by weight reached at the end of the heat-up phase will be relatively constant over the entire range of the preferred process parameters. After termination of the process as described herein, the heated pancreatin may again be exposed to normal ambient conditions (e.g. room temperature and normal moisture conditions). The decrease in viral contaminants in the pancreatin which has been achieved via the process described herein will be maintained under these normal ambient conditions because any viral contaminants as described herein will have been irreversibly deactivated under the process conditions. 
     In another embodiment, the pancreatin is heated for a period of from about 1 hour to about 36 hours, more preferred for a period of from about 8 hours to about 30 hours, yet more preferred for a period of from about 10 hours to about 24 hours. In an additional embodiment of such process, the dispersed pancreatin is heated for a period of from about 1 hour to about 36 hours, such as, e.g., about 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, 30 hours, 31 hours, 32 hours, 33 hours, 34 hours, 35 hours, or 36 hours, and in another embodiment of such process, the dispersed pancreatin is heated for a period of from about 10 hours to about 30 hours. 
     In another embodiment, the pancreatin is heated at a temperature of from 85° C. to about 100° C., specifically at a temperature of 85° C., 86° C., 87° C., 88° C., 89° C., 90° C., 91° C., 92° C., 93° C., 94° C., 95° C., 96° C., 97° C., 98° C., 99° C., 100° C., or any temperature in the ranges between these given integer temperature values. In a further embodiment of such process, the pancreatin is heated at a temperature of from 85° C. to about 95° C., specifically at a temperature of 85° C., 86° C., 87° C., 88° C., 89° C., 90° C., 91° C., 92° C., 93° C., 94° C., 95° C. or any temperature in the ranges between these given integer temperature values. In other alternatives of this embodiment, the pancreatin is heated at a temperature of from about 90° C. to about 100° C., specifically at a temperature of 90° C., 91° C., 92° C., 93° C., 94° C., 95° C., 96° C., 97° C., 98° C., 99° C., 100° C., or any temperature in the ranges between these given integer temperature values. In a more preferred alternative of this embodiment the pancreatin is heated at a temperature of from about 90° C. to about 95° C., specifically at a temperature of 90° C., 91° C., 92° C., 93° C., 94° C., 95° C. or any temperature in the ranges between these given integer temperature values. 
     In another embodiment of such a process, the solvents content of the pancreatin is from about 0.1% to about 3.5% by weight and the pancreatin is heated for a period of from about 8 hours to about 30 hours at a temperature of from 85° C. to about 100° C. 
     In another embodiment of such a process, the solvents content of the pancreatin is from about 0.1% to about 3.0% by weight and the pancreatin is heated for a period of from about 10 hours to about 30 hours at a temperature of from 85° C. to about 95° C. 
     In another embodiment of such a process, the solvents content of the pancreatin is from about 0.1% to about 1.6% by weight and the pancreatin is heated for a period of from about 10 hours to about 30 hours at a temperature of from 85° C. to about 95° C. 
     With each single and combined embodiments of such process, the concentration of one or more biological contaminants in the pancreatin is decreased, in particular the concentration of one or more viral contaminants, without substantially affecting the activity of the pancreatin. In one embodiment, the concentration of highly resistant viruses in the pancreatin, more preferably in the concentration of the porcine parvovirus, is decreased. 
     Also disclosed is a pancreatin obtainable by the process described herein. All provisions made above for the process described herein are also applicable for the pancreatin obtainable by such process. 
     Another embodiment is directed to a process for manufacturing a pharmaceutical composition comprising pancreatin in accordance with the process described herein wherein such pharmaceutical composition is in a dosage form suitable for oral administration. The oral dosage form can be for immediate and/or modified release, such dosage form can be tablets, microtablets, pellets, micropellets, microspheres, granules, granulates, powders, suspensions, emulsions, dispersions, capsules sachets as well as other dosage forms. 
     In one embodiment of such process for the manufacturing of a pharmaceutical composition, the pancreatin and/or its dosage form is further coated with a gastric acid resistant coating. 
     In another embodiment of such process for the manufacture of a pharmaceutical composition, the optionally gastric acid resistant coated pancreatin or its dosage form is further filled into sachets and/or capsules. 
     Described herein is a pharmaceutical composition comprising
         (1) a pharmacologically effective quantity of pancreatin wherein said pancreatin has been heated in the form of a dispersed pancreatin containing one or more solvents, wherein the total amount of solvents present in the pancreatin is less than about 9% by weight at any point during the heating step, to a temperature of at least 85° C.; wherein the titer level of a viral contaminant present in the pancreatin after heating is at least about 1000 times less than the titer level of the viral contaminant present in the pancreatin prior to heating; and   (2) one or more pharmaceutically acceptable excipients.       

     In an embodiment of such pharmaceutical composition, the pancreatin is present in a dosage form which is suitable for oral administration. The oral dosage form can be for immediate and/or modified release, such dosage form can be tablets, microtablets, pellets, micropellets, microspheres, granules, granulates, powders, suspensions, emulsions, dispersions, capsules, sachets, as well as other dosage forms. 
     In another embodiment of such pharmaceutical composition the pancreatin and/or the pharmaceutically acceptable excipients are further coated with a gastric acid resistant coating. 
     Also disclosed is a pharmaceutical composition in the form of a capsule or sachet, the capsule or sachet comprising the pancreatin described herein. 
     In an embodiment of such pharmaceutical composition, the composition further comprises pharmaceutically acceptable excipients. 
     In another embodiment of such pharmaceutical composition, the composition is in a dosage form suitable for oral administration. The oral dosage form can be for immediate and/or modified release, such dosage form can be tablets, microtablets, pellets, micropellets, microspheres, granules, granulates, powders, suspensions, emulsions, dispersions, capsules, sachets as well as other known dosage forms. 
     In another embodiment of such pharmaceutical composition, the pancreatin and/or the pharmaceutically acceptable excipients and/or its dosage form is further coated with a gastric acid resistant coating. 
     The pharmaceutical compositions described herein may comprise pharmaceutically acceptable excipients. Pharmaceutically acceptable excipients for use in the compositions described above are exemplified by: sugars such as lactose, sucrose, mannitol and sorbitol; starches such as cornstarch, tapioca starch and potato starch; cellulose and derivatives such as sodium carboxymethyl cellulose, ethyl cellulose and methyl cellulose; calcium phosphates such as dicalcium phosphate and tricalcium phosphate; sodium sulfate; calcium sulfate; polyvinylpyrrolidone; polyvinyl alcohol; stearic acid; alkaline earth metal stearates such as magnesium stearate and calcium stearate; stearic acid; vegetable oils such as peanut oil, cottonseed oil, sesame oil, olive oil and corn oil; non-ionic, cationic and anionic surfactants; ethylene glycol polymers; betacyclodextrin; fatty alcohols; and hydrolyzed cereal solids, as well as other non-toxic compatible fillers, binders, disintegrants, agents, e.g. talcum; buffers, preservatives, antioxidants, lubricants, flavoring and other excipients which are acceptable for use in pharmaceutical formulations. 
     Generally, a pharmaceutical composition according to the invention may comprise about 0.1% to about 100%, such as, e.g., about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%, preferably of from about 25% to about 90%, such as, e.g., 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%, more preferably from about 50% to about 90%, such as, e.g., 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90% by weight, of pancreatin and the remaining proportions, if any, being made up by pharmaceutically acceptable auxiliaries, excipients and/or carriers. 
     In one embodiment, the pharmaceutical compositions comprise (a) from about 50% to about 90% by weight of pancreatin obtained by the process described herein, and (b) from about 10% to about 50% by weight, of pharmaceutically acceptable excipients, e.g. ethylene glycol polymers, in particular ethylene glycol 2000, 3000, 4000, 6000, 8000 and/or 10000. 
     In another embodiment, the pharmaceutical compositions comprise (a) from about 55% to about 85% by weight of pancreatin obtained by the process described herein, (b) from about 5% to about 35% by weight of ethylene glycol polymers, (c) from about 1.0% to about 20% by weight of propan-2-ol, and (d) optionally from 0% to about 10% by weight of paraffin. Other compositions comprising pancreatin are e.g. disclosed in EP 0 583 726 and in EP 0 826 375. 
     The processes described herein may be carried out at any temperature of at least 85° C. which does not result in an unacceptable level of damage to the pancreatin. In accordance with the processes described herein, an “acceptable level” of damage may vary depending upon certain features of the particular processes described herein being employed, such as the nature and characteristics of the particular pancreatin being used, and/or the intended use of the pancreatin being heated, and can be determined empirically by one skilled in the art. An “unacceptable level” of damage would therefore be a level of damage that would preclude the safe and/or effective use of the pancreatin being heated. The particular level of damage to a given pancreatin sample may be determined using any of the methods and techniques known to one skilled in the art. 
     When used in pharmaceutical compositions, a residual enzyme activity after heating of 50% or more, preferably about 70% or more, more preferably about 85% or more and most preferably about 90% or more, of the original enzyme activity is desirable. 
     To establish the conditions to minimize the level of enzyme activity decrease, experiments were conducted. In several series of such experiments, the original enzyme activity and the residual enzyme activity of lipase as the leading enzyme were determined before and after heating at certain experimental conditions which are described in detail below. 
     In a similar series of experiments, the decrease in the concentration of biological contaminants therein was determined. In such experiments, the virus titer values of the highly resistant porcine parvovirus as the leading virus were determined before and after heating under certain experimental conditions which are described in detail below. For each experiment, porcine parvovirus-spiked porcine pancreatin samples were utilized. 
     The virus titers including standard deviations of the PPV-spiked samples were determined by endpoint titration and subsequent calculation of the half-maximum tissue culture infectious dose (=TCID 50 ) according to the Spearman-Kaerber formula as described in the German “Bundesanzeiger” No. 84, May 4, 1994. Therefore, serial one-to-three dilutions of the aliquots were made using cell culture medium and aliquots of each dilution were added using eight-fold replicates in 96-well microtiter plates containing the corresponding target cells. Following an incubation period of six to seven days, the target cells were inspected microscopically for a virus-induced CPE. The virus titers were calculated as mentioned above and these are presented as log 10  TCID 50  per ml with 95% confidence limits. The capacity of the treatment to deactivate or remove viruses was described by means of the logarithmic reduction factors (LRF). This LRF was calculated according to the EC guideline 111/8115/89-EN (now replaced by CPMP/BWP/268/95), appendix II as the difference of the viral titers between the hold control samples and the samples which had been exposed to heating. 
     When used in pharmaceutical compositions, a decrease in the concentration of biological contaminants therein, in particular a decrease in the concentration of viral contaminants, of at least about 3.0, preferably about 3.5, more preferably about 4.0 and most preferably about 4.5 or more log titer reductions is desirable. To comply with authority recommendations on the viral safety of biological products (see e.g. CPMP/BWP/268/95), a process which can provide 4.0 log titer reductions is usually considered robust in terms of virus deactivation and therefore deemed satisfactory. 
     A log titer reduction thereby indicates the reduction in virus concentration in logarithmic units to the basis 10 (=log 10 ), i.e. a log titer reduction of 3 would comprise a 1000-9999-fold reduction of the viral concentration, while a log titer reduction of 4 would comprise a 10000-99999-fold reduction of the viral concentration. A process for sterilizing pancreatin can be said to be most effective if application of this process results in a satisfactory decrease of even highly resistant viruses in the pancreatin. 
     To establish the conditions for the most effective log titer reduction, experiments were conducted. Due to technical limitations, it is currently only possible to determine decreases in the concentration of biological contaminants in pancreatin samples of about 4.5 to about 5.0 log titers (detection limit). 
     In a first series, experiments were conducted in which the lipase activity after heating for specific periods and different but constant temperatures was determined. In the first experiment, the lipase activity after heating for 0, 2, 4, 6, 12, 15, 18, 21, 24 and 30 hours at 80° C. at a solvents content of about 1% was determined. In a second experiment, the lipase activity after heating for 0, 6, 12, 15, 18, 21, 24 and 30 hours at 85° C. at a solvents content of 1% was determined. In a third experiment, the lipase activity after heating for 0, 6, 12, 15, 18, 21, 24 and 30 hours at 90° C. at a solvents content of 1% was determined. In a fourth experiment, the lipase activity after heating for 0, 6, 12, 15, 18, 21, 24 and 30 hours at 95° C. at a solvents content of 1% was determined. In a fifth experiment, the lipase activity after heating for 0, 6, 12, 15, 18, 21, and 24 hours at 100° C. at a solvents content of 1% was determined. The results of this first series of experiments are shown in table 1 and illustrated in  FIG. 1 . 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Heating of Pancreatin at 80° C., 85° C., 90° C., 95° C. and 100° C.  
               
               
                 (1% solvents content); the data presented in table 1 are mean values 
               
               
                 from two incubations; n/a = not applicable; Temp. = Temperature 
               
            
           
           
               
               
            
               
                 Incubation 
                 Lipase residual activity [%] 
               
               
                 time 
                 Temp. 
               
            
           
           
               
               
               
               
               
               
            
               
                 [h] 
                 80° C. 
                 85° C. 
                 90° C. 
                 95° C. 
                 100° C. 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 0 
                 100.0  
                 100.0  
                 100.0  
                 100.0  
                 100.0  
               
               
                 2 
                 99.3 
                 n/a 
                 n/a 
                 n/a 
                 n/a 
               
               
                 4 
                 99.0 
                 n/a 
                 n/a 
                 n/a 
                 n/a 
               
               
                 6 
                 98.8 
                 98.9 
                 95.0 
                 91.1 
                 84.0 
               
               
                 12 
                 97.7 
                 96.2 
                 91.7 
                 86.1 
                 71.4 
               
               
                 15 
                 96.5 
                 94.7 
                 90.6 
                 84.2 
                 66.3 
               
               
                 18 
                 94.6 
                 93.5 
                 88.6 
                 80.1 
                 60.3 
               
               
                 21 
                 93.6 
                 93.5 
                 87.0 
                 77.8 
                 56.0 
               
               
                 24 
                 92.5 
                 92.1 
                 85.8 
                 77.8 
                 52.8 
               
               
                 30 
                 91.3 
                 90.7 
                 83.7 
                 74.8 
                 n/a 
               
               
                   
               
            
           
         
       
     
     As can be seen from table 1 and from  FIG. 1  for a constant solvents content of 1%, the lipase activity decreases as incubation time increases at a given temperature. Furthermore, the lipase activity declines to a greater extent at high temperatures at a given incubation time. When used in pharmaceutical compositions, it follows that heating conducted for a period of up to and including 30 hours at temperatures up to and including 95° C. provide pancreatin having acceptable residual enzyme activity at a solvents content of 1%. When used in pharmaceutical compositions, it follows further that heating conducted for a period of up to and including 24 hours at temperatures up to and including 100° C. provide pancreatin having acceptable residual enzyme activity at a solvents content of 1%. 
     In a second series, two experiments were conducted in which the lipase activity at a solvents content of 3% was determined after heating. In the first experiment, the lipase activity after heating for 0, 2, 4, 6, 8, 15, 24 and 48 hours at 90° C. and 95° C. at a solvents content of 3% was determined. The results of this second series of experiments are shown in table 2 and illustrated in  FIG. 2 . 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Heating of Pancreatin at 90° C. and 95° C.  
               
               
                 (3% solvents content). 
               
            
           
           
               
               
            
               
                 Incubation  
                 Lipase residual activity [%] 
               
               
                 time 
                 Temperature 
               
            
           
           
               
               
               
            
               
                 [h] 
                 90° C.  
                 95° C. 
               
               
                   
               
            
           
           
               
               
               
            
               
                  0 
                 100.0 
                 100.0 
               
               
                  2 
                 94.1 
                 95.1 
               
               
                  4 
                 91.0 
                 90.2 
               
               
                  8 
                 86.8 
                 81.4 
               
               
                 15 
                 84.0 
                 66.0 
               
               
                 24 
                 71.4 
                 54.1 
               
               
                 48 
                 53.5 
                 31.3 
               
               
                   
               
            
           
         
       
     
     As can be seen from table 2 and from  FIG. 2  for a constant solvents content of 3%, the lipase activity decreases as incubation time increases at a given temperature. Furthermore, the lipase activity declines to a greater extent at high temperatures at a given incubation time. When used in pharmaceutical compositions, it follows that heating conducted for a period of up to and including 48 hours at temperatures up to and including 90° C. provide pancreatin having acceptable residual enzyme activity at a solvents content of 3%. When used in pharmaceutical compositions, it follows further that heating conducted for a period of up to and including 24 hours at temperatures up to and including 95° C. provide pancreatin having acceptable residual enzyme activity at a solvents content of 3%. 
     In a third series of experiments, the lipase activity was determined after heating for 0.5, 1.0 and 3.0 hours at 80° C. at different but constant solvents contents of 3%, 6%, 9% and 12%, respectively. The results of these experiments are shown in table 3 and are illustrated in  FIG. 3 . 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Heating Pancreatin at 80° C. with a solvents  
               
               
                 content of 3%, 6%, 9% and 12%, respectively. 
               
            
           
           
               
               
            
               
                   
                 Lipase residual activity [%] 
               
               
                 Incubation 
                 Solvents Content 
               
            
           
           
               
               
               
               
               
            
               
                 time [h] 
                 3% 
                 6% 
                 9% 
                 12% 
               
               
                   
               
               
                 0   
                 100.0 
                 100.0 
                 100.0 
                 100.0 
               
               
                 0.5 
                 101.2 
                  92.8 
                  63.0 
                  37.8 
               
               
                 1.0 
                 100.5 
                  88.2 
                  50.7 
                  23.9 
               
               
                 3.0 
                 100.1 
                  73.5 
                  33.5 
                  12.8 
               
               
                   
               
            
           
         
       
     
     It can be seen from table 3 and from  FIG. 3  for a constant temperature but different solvents contents of 3%, 6%, 9% and 12%, respectively, the lipase activity decreases as incubation time increases at 80° C. Furthermore, the lipase activity declines to a greater extent at high solvents contents at a given incubation time. When used in pharmaceutical compositions, it follows that heating conducted for a period of up to and including 3 hours at a temperature of 80° C. provide pancreatin having acceptable residual enzyme activity at a solvents content of 6%. When used in pharmaceutical compositions, it follows further that heating conducted for a period of up to and including 1 hour at a temperature of 80° C. provide pancreatin having acceptable residual enzyme activity at a solvents content of 9%. 
     This series of experiments demonstrates that enzymes are sensitive to extended periods of heat and sensitive to high solvents contents. Their high original activity is maintained if heating occurs under controlled conditions, i.e., over short periods, and/or at low temperatures, and/or at low solvents contents. In an embodiment, the high original enzyme activity is maintained if the enzymes are heated at low temperatures and at low solvents contents over a short period of time. 
     To evaluate the reduction in the porcine parvovirus, the log 10  TCID 50  after heating for 6, 12, 15, 18, 21, 24 and 30 hours at 80° C., 85° C., 90° C., 95° C. and 100° C. were determined at a constant solvent contents of 1%. The results of these experiments are shown in table 4. In table 4 and the following tables, titers which are indicated as “smaller than” (≤) express the detection limit. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Heating of PPV-spiked pancreatin at 80° C., 85° C., 90° C., 95° C.  
               
               
                 and 100° C. with a solvents content of 1%; n/a = not applicable; 
               
               
                 Temp. = Temperature; h = hours; LTR = Log Titer Reduction. 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 the 109 10  TCID 50  of PPV-spiked Pancreatin 
               
               
                 Incubation 
                 Incubation Temp.: 
               
            
           
           
               
               
               
               
               
               
            
               
                 Time [h] 
                 80° C.  
                 85° C.  
                 90° C.  
                 95° C.  
                 100° C. 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                  0 h 
                 7.2 
                 7.2 
                 7.8 
                 7.8 
                 7.8 
               
               
                  6 h 
                 6.9 
                 6.0 
                 5.5 
                 4.7 
                 n/a 
               
               
                 12 h 
                 5.6 
                 ≤5.1 
                 4.0 
                 3.9 
                 ≤3.8 
               
               
                 15 h 
                 5.8 
                 ≤4.1 
                 ≤3.8 
                 ≤3.8 
                 n/a 
               
               
                 18 h 
                 ≤5.0 
                 ≤4.0 
                 ≤3.8 
                 ≤3.8 
                 n/a 
               
               
                 21 h 
                 ≤4.8 
                 ≤3.9 
                 ≤3.8 
                 ≤3.8 
                 n/a 
               
               
                 24 h 
                 ≤4.6 
                 ≤3.9 
                 ≤3.8 
                 ≤3.8 
                 ≤3.8 
               
               
                 30 h 
                 ≤4.2 
                 ≤3.8 
                 ≤3.8 
                 ≤3.8 
                 n/a 
               
               
                 18 h hold 
                 7.9 
                 7.5 
                 7.7 
                 7.8 
                 7.8  
               
               
                   
                   
                   
                   
                   
                 (24 h hold) 
               
               
                 30 h hold 
                 7.5 
                 7.5 
                 7.4 
                 7.3 
                 n/a 
               
               
                 LTR (18 h 
                 ≥2.9 
                 ≥3.5 
                 3.9 
                 4.0 
                 n/a 
               
               
                 hold 
                   
                   
                   
                   
                   
               
               
                 versus 18 h 
                   
                   
                   
                   
                   
               
               
                 x° C. ) 
                   
                   
                   
                   
                   
               
               
                 LTR (30 h 
                 ≥3.3 
                 ≥3.7 
                 3.6 
                 3.5 
                 4.0  
               
               
                 hold 
                   
                   
                   
                   
                 (24 h hold  
               
               
                 versus 30 h  
                   
                   
                   
                   
                 vs. 24 h at 
               
               
                 at x° C. ) 
                   
                   
                   
                   
                 100° C. ) 
               
               
                   
               
            
           
         
       
     
     Additional pancreatin powder batches 2 to 4 were prepared and processed at 85° C. as described above in table 4 and below in Example 13. To evaluate the reduction in the porcine parvovirus, again the log 10  TCID 50  after heating for 6, 12, 15, 18, 21, 24 and 30 hours at 85° C. were determined at a constant solvent content of 1%. The results of these additional experiments are shown in table 4a. 
     
       
         
           
               
             
               
                 TABLE 4a 
               
             
            
               
                   
               
               
                 Heating of 3 different batches of PPV-spIked pancreatin  
               
               
                 at 85° C. with a solvents content of 1%. Values 
               
               
                 given as “±” denominate the 95% confidence  
               
               
                 intervals. “*” means that no infectious virus  
               
               
                 could be detected; Temp. = Temperature;  
               
               
                 h = hours; LTR = Log Titer Reduction. 
               
            
           
           
               
               
            
               
                   
                 the log 10  TCID 50  of PPV-spiked  
               
               
                   
                 Pancreatin/85° C.  
               
               
                 Incubation 
                 Batch No. 
               
            
           
           
               
               
               
               
            
               
                 Time [h]/Temp. 
                 2 
                 3 
                 4 
               
               
                   
               
               
                  0 h 
                   7.5 ± 0.2 
                   7.5 ± 0.2 
                   7.2 ± 0.3 
               
               
                  6 h 
                   5.9 ± 0.3 
                   5.6 ± 0.2 
                   5.9 ± 0.2 
               
               
                 12 h 
                   4.9 ± 0.3 
                 ≤4.6 ± 0.4 
                   4.8 ± 0.3 
               
               
                 15 h 
                 ≤4.3 ± 0.3 
                 ≤4.3 ± 0.3 
                 ≤4.4 ± 0.3 
               
               
                 18 h 
                 ≤4.1 ± 0.3 
                 ≤3.8 ± 0.2 
                 ≤4.2 ± 0.1 
               
               
                 21 h 
                 ≤3.9 ± 0.2 
                 ≤3.8 ± 0.2 
                 ≤3.9 ± 0.2 
               
               
                 24 h 
                 ≤3.7 ± 0.1 
                 3.7* 
                 ≤3.8 ± 0.1 
               
               
                 30 h 
                 ≤3.7 ± 0.1 
                 ≤3.7 ± 0.1 
                 3.8* 
               
               
                 18 h hold 
                   7.7 ± 0.2 
                   7.7 ± 0.3 
                   7.7 ± 0.3 
               
               
                 30 h hold 
                   7.7 ± 0.3 
                   7.4 ± 0.3 
                   7.6 ± 0.3 
               
               
                 LTR (18 h  
                 ≥3.6 ± 0.4 
                 ≥3.9 ± 0.4 
                 ≥3.5 ± 0.3 
               
               
                 hold versus 
                   
                   
                   
               
               
                 18 h at 85° C.) 
                   
                   
                   
               
               
                 LTR (30 h hold 
                 ≥4.0 ± 0.3 
                 ≥3.7 ± 0.3 
                 ≥3.8 ± 0.3 
               
               
                 versus 30 h  
                   
                   
                   
               
               
                 at 85° C.) 
               
               
                   
               
            
           
         
       
     
     Table 5 shows the log titer reduction in comparison to the beginning of the experiment.  FIG. 4  illustrates the log titer reduction of PPV-spiked pancreatin after heating at 80° C., 85° C., 90° C., 95° C. and 100° C. with a solvents content of 1%. 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Log Titer Reduction after heating of PPV-spIked pancreatin  
               
               
                 at 80° C., 85° C., 90° C., 95° C. and 100° C. with  
               
               
                 a solvents content of 1%; n/a = not applicable;  
               
               
                 Temp. = Temperature. 
               
            
           
           
               
               
            
               
                 Incubation 
                 Log Titer Reduction of porcine parvovirus 
               
               
                 time  
                 Temp. 
               
            
           
           
               
               
               
               
               
               
            
               
                 [h] 
                 80° C.  
                 85° C.  
                 90° C.  
                 95° C.  
                 100° C. 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                  0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                  6 
                 0.3 
                 1.2 
                 2.3 
                 3.1 
                 n/a 
               
               
                 12 
                 1.6 
                 ≥2.1 
                 3.8 
                 3.9 
                 ≥4.0 
               
               
                 15 
                 1.4 
                 ≥3.1 
                 ≥4.0 
                 ≥4.0 
                 n/a 
               
               
                 18 
                 ≥2.2 
                 ≥3.2 
                 ≥4.0 
                 ≥4.0 
                 n/a 
               
               
                 21 
                 ≥2.4 
                 ≥3.3 
                 ≥4.0 
                 ≥4.0 
                 n/a 
               
               
                 24 
                 ≥2.6 
                 ≥3.3 
                 ≥4.0 
                 ≥4.0 
                 4.0 
               
               
                 30 
                 ≥3.0 
                 ≥3.4 
                 ≥4.0 
                 ≥4.0 
                 n/a 
               
               
                   
               
            
           
         
       
     
     As can be seen from tables 4 and 5 as well as from  FIG. 4  for a constant solvents content of 1%, the log titer reduction increases as incubation time increases at a given temperature. Furthermore, the log titer reduction declines to a greater extent as temperature increases. When used in pharmaceutical compositions, it follows that heating conducted for a period of up to and including 30 hours at a temperature of 80° C. provide pancreatin having an acceptable decrease in the concentration of biological contaminants therein at a solvents content of 1%. Experiments conducted for a period of 12 hours and at a temperature of 90° C. provide pancreatin having a decrease in the concentration of biological contaminants therein at a solvents content of 1%. Experiments conducted for a period of 15 hours and at a temperature of 90° C. provide pancreatin having an even larger decrease in the concentration of biological contaminants therein at a solvents content of 1%. 
     From table 4a it can be seen that the authorities&#39; recommendations on the viral safety of biological products (see e.g. CPMP/BWP/268/95) can be met when the parameters as given in table 4a are applied, i.e. 4.0 log titer reductions may be reached at process temperatures of 85° C. (see e.g. batch 2, LTR after 30 hours). Similar experiments with additional batches processed at 80° C. showed that the authorities&#39; recommendations on the viral safety of biological products could not be met, i.e. that 4.0 log titer reductions could not be reached at process temperatures of 80° C. 
     In another series of experiments, the log 10  TCID 50  after heating for up to 12 hours at a constant temperature and at different but constant solvents content of 1% and 3% respectively was determined. The results of these experiments are shown in table 6. 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Heating of PPV-spIked pancreatin at 90° C. and 95° C.  
               
               
                 with a solvent content of 1% and 3%, respectively. 
               
            
           
           
               
               
               
            
               
                   
                   
                 The log 10  TCID 50  of PPV-spiked Pancreatin 
               
               
                   
                   
                 Temperature 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                 90° C., 1% 
                 90° C., 3% 
                 95° C., 1% 
                 95° C., 3% 
               
               
                   
                 Incubation 
                 solvents 
                 solvents 
                 solvents 
                 solvents 
               
               
                   
                 time [h] 
                 content 
                 content 
                 content 
                 content 
               
               
                   
                   
               
               
                   
                 0 
                 8.2 
                 8.2 
                 8.2 
                 8.2 
               
               
                   
                 3 
                 6.8 
                 6.2 
                 6.4 
                 6.1 
               
               
                   
                 6 
                 5.9 
                 5.8 
                 6.1 
                 5.1 
               
               
                   
                 12  
                 5.0 
                 4.9 
                 4.6 
                 5.0 
               
               
                   
                   
               
            
           
         
       
     
     Table 7 shows the log titer reduction (for the results as presented in table 5) in porcine parvovirus relative to the initial amount.  FIG. 5  illustrates the log titer reduction of PPV-spiked pancreatin after heating at 90° C. and 95° C. with a solvents content of 1% and 3%, respectively. The experiments leading to the results as presented in tables 6 and 7 were performed under slightly different conditions compared with the experiments leading to the results as presented in table 5. 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Log Titer reduction after heating of PPV-spIked pancreatin at  
               
               
                 90° C. and 95° C. with a solvents content of  
               
               
                 1% and 3%, respectively. 
               
            
           
           
               
               
               
            
               
                   
                   
                 Log Titer Reduction of porcine parvovirus (PPV) 
               
               
                   
                   
                 Temperature 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                 90° C., 1% 
                 90° C., 3% 
                 95° C., 1% 
                 95° C., 3% 
               
               
                   
                 Incubation 
                 solvents 
                 solvents 
                 solvents 
                 solvents 
               
               
                   
                 time [h] 
                 content 
                 content 
                 content 
                 content 
               
               
                   
                   
               
               
                   
                 0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 3 
                 1.4 
                 2.0 
                 1.8 
                 2.1 
               
               
                   
                 6 
                 2.3 
                 2.4 
                 2.1 
                 3.1 
               
               
                   
                 12  
                 3.2 
                 3.3 
                 3.6 
                 3.2 
               
               
                   
                   
               
            
           
         
       
     
     It can be seen from tables 6 and 7 as well as from  FIG. 5  for a constant solvents content of 1% and 3% respectively, that the log titer reduction increases as incubation time increases at a given temperature. Furthermore, the log titer reduction increases to a greater extent at 3% solvents contents as opposed to 1%. For-use in pharmaceutical compositions, it follows that heating for a period of at least 6 hours at a temperature of 95° C. will provide pancreatin having an acceptable decrease in the concentration of biological contaminants therein at a solvents content of 3%. For use in pharmaceutical compositions, it follows that heating conducted for a period of 12 hours at a temperature of 90° C. provide pancreatin having an acceptable decrease in the concentration of biological contaminants therein at a solvents content of 1% or 3%, respectively. 
     This series of experiments demonstrates that the concentration of porcine parvovirus can be effectively reduced by heating under the conditions set forth above. It can be concluded from the above experiments that the reduction is more effective at high temperatures and/or over a long period of time and/or at higher solvents content. In an embodiment, the concentration of the porcine parvovirus can be effectively reduced if the virus is heated at a suitably elevated temperature and solvents contents over a sufficient period of time. 
     The results obtained for the decrease in the concentration of porcine parvovirus are in contrast to what has been demonstrated for enzymes. Hence, the skilled person in the art is faced with the challenge of designing a process of sterilizing pancreatin in such a way that a high level of activity of the different digestive enzymes is maintained while at the same time the concentration of one or more biological contaminants, in particular of viruses, therein is reduced to an acceptable level. 
     From the above experiments it can be seen that the concentration of porcine parvovirus in pancreatin under experimental conditions is reduced while the lipase activity level remains acceptable for the use in pharmaceutical compositions. These experimental conditions can be summarized as follows: 
     Heating for a period up to 48 hours at a temperature of at least 85° C. at a solvent content of less than about 9% by weight. 
     The steps of adjusting the solvents content and heating may occur at any pressure which is not deleterious to the pancreatin being heated. Generally, the disclosed processes are conducted at atmospheric, reduced or elevated pressure. Suitable pressures can be determined empirically by one skilled in the art. In an embodiment, the processes are conducted at atmospheric or reduced pressure. In another embodiment, the processes are conducted at atmospheric pressure. According to another embodiment, the processes described herein are conducted under vacuum while being sterilized. 
     Similarly, according to the processes described herein, heating may occur under any atmosphere that is not deleterious to the pancreatin being treated. Typically, the processes described herein are conducted in standard atmosphere. According to one embodiment, the disclosed processes are conducted in a low oxygen atmosphere or an inert atmosphere. When an inert atmosphere is employed, the atmosphere is preferably composed of nitrogen or a noble gas, such as helium or argon, more preferably a higher molecular weight noble gas, and most preferably argon. It will be appreciated that the combination of one or more of the features described herein may be employed to further minimize undesirable effects upon the processes described herein, while maintaining adequate effectiveness of the processes on the biological contaminant(s). 
     The solvents content of pancreatin may be reduced by any of the methods and techniques known to those skilled in the art for reducing solvent from a preparation of one or more digestive enzymes without producing an unacceptable level of damage to the preparation. Such methods include, but are not limited to, evaporation, concentration, centrifugal concentration, vitrification, addition of solute, lyophilization (with or without the prior addition of ascorbate) and spray-drying. 
     A preferred method for reducing the solvents content of pancreatin is concentration, which may be accomplished by any of the methods and techniques known to those skilled in the art. Concentration may be achieved either by controlled heating of the preparation and subsequent evaporation of the unwanted solvent or by evaporation via reduced pressure. Also a combination of these two methods under mild conditions, evaporation at low temperature under reduced pressure, may be applied in order to achieve the desired solvents content. Regardless of the method used, the resulting preparation will then have the desired solvents content. 
     The processes described herein may be conducted at any scale, at laboratory scale with preparations having a mass from 1 g to 1000 g; at pilot plant scale with preparations having a mass from 1 kg to 50 kg and a production scale with preparations having a mass from at least 100 kg, preferably from 200 kg to 1500 kg. 
     EXAMPLES 
     The following examples are illustrative, and not meant to limit the claimed invention. Other suitable modifications and adaptations are of the variety normally encountered by those skilled in the art and are fully within the spirit and scope of the claimed invention. 
     Determination of Enzymatic Activity 
     The determination of the lipase activity was performed according to a Solvay testing method which is based on the monograph of pancreas powder in Ph. Eur. (Pancreas Powder, European Pharmacopoeia 5.0, 2179-2182; 01/2005:0350). 
     Determination of Solvent Content 
     The solvents contents related as water referenced herein refer to levels determined by the FDA approved, modified Karl Fischer method (Meyer and Boyd, Analytical Chem., 31:215-219, 1959; May, et al., J. Biol. Standardization, 10:249-259, 1982; Centers for Biologics Evaluation and Research, FDA, Docket No. 89D-0140, 83-93; 1990). Quantitation of the contents of other solvents may be determined by means known to those of skill in the art, depending on which solvent is employed. Further suitable means for determining solvent contents in the pancreatin during or after the process disclosed herein, which are also included in the present disclosure, are e.g. thermogravimetric methods (including infrared drying and microwave drying), spectrometric methods (including infrared spectroscopy, microwave spectroscopy and nuclear magnetic resonance spectroscopy), conductometry, decametry, or thermal conduction. Usually, the preferred method for determining the solvents contents in pancreatin is a thermogravimetric method (e.g. determination of “loss on drying”), since this method would cover all liquids which may be present in the pancreatin, comprising e.g. water and enzyme friendly organic solvents like isopropanol. Thermogravimetric methods are in particular suited for measuring solvents contents of about 9%-3.5% by weight in the pancreatin. Where lower solvents contents are to be determined in the pancreatin, e.g. solvents contents below about 3.5%, more typically of less than 3%, even more typically of less than 1.6% by weight, the proportion of water present in the solvents content of pancreatin will typically outweigh the proportion of enzyme friendly organic solvent present in the pancreatin. It may therefore be advantageous to measure solvents contents below about 3.5%, more typically of less than 3%, even more typically of less than 1.6% by weight by using the more sensitive Karl Fischer method or a modification thereof. For technical batch sizes and continuous measuring, infrared spectroscopic determination of the solvent contents is advantageous, in particular where solvents contents below about 3.5%, more typically of less than 3%, even more typically of less than 1.6% by weight are to be measures, e.g. in the steady state of the heating process after the pre-heating. Preferred are near infrared spectroscopy determination methods (NIR) which are known to those skilled in the art. The infrared spectoscopic methods will typically need to be standardized against a reference method which can be the Karl-Fischer water titration method or a modification thereof. For the reasons as outlined above, the most preferred method of measuring the total solvents content in a pancreatin is a combination of a thermogravimetric method (i.e. determining the loss on drying in the pancreatin, in particular for a pancreatin with a higher solvents content) with a Karl Fischer method or a modification thereof (i.e. determining the remaining water content in the pancreatin, in particular for a pancreatin with a lower solvents content. 
     Determination of Porcine Parvovirus Reduction 
     The virus titers within the treated samples were determined by virus endpoint titration and the TCID 50  was calculated according to the Spearman-Kaerber formula as described in the Bundesanzeiger No. 84, May 4 1994. In order to circumvent incompatibility of the pancreatin with the detector Pk-13-cells (porcine kidney), the test material was diluted by 3 log titers (e.g. 1:2000) prior to titration in each case. The ability of the treatment to deactivate or remove viruses was described by means of the logarithmic reduction factors. In order to be able to estimate the reduction of virus titers independently from obligatory decrease of infectivity during the incubation period, which to some extent may result from the properties of the test material itself, hold samples were taken. The logarithmic titer reduction (LTR) of the samples was calculated as the difference between the virus titer (log 10  TCID 50 /ml) of the hold sample and the final point sample according to the EC guideline III/8115/89-EN, appendix II (now replaced by CPMP/BWP/268/95). 
     Heating 
     For laboratory scale, heating was performed in a drying oven (e.g. from company Memmert, ULE 400) or rotary evaporator (e.g. from company Buchi, R-144) with a water bath (e.g. Buchi B-480). In the pilot plant scale, a vacuum dryer (company: Hosokawa, Vrieco-Nauta®, volume 120 L) was used. In the production scale, a vacuum dryer (company: Hosokawa, Vrieco-Nauta®, volume 4000 L) was used. 
     Preparation of Standardized Pancreatin Powder 
     50 kg to 1000 kg of moist pancreatin (initial solvents content 40-50%) was dried in a vacuum dryer with continuous stirring. The temperature was increased stepwise from 60° C. to 95° C. Drying was then carried out at a temperature of at least 70° C. until a solvents content of &lt;3.5% is reached. To obtain pancreatin powder samples of solvent contents of 6%, 9% or 12% by weight, respectively, samples may be taken at appropriate earlier points during the drying process in a known manner. 
     a) Further steps for the preparation of standardized pancreatin powder on a laboratory scale include heating at the desired temperature until a solvents content of 1%, or 3% by weight, respectively, was reached in accordance with the starting requirements of the experiments described below (examples 1 to 11 below). 
     For an alternative preparation of standardized pancreatin powder having a solvents content of 6%, 9% or 12% by weight, respectively, an appropriate amount of a solvent e.g., water, propan-2-ol or mixtures thereof, may be added to a pancreatin powder with a solvents content of 3.5% by weight, and the obtained moistened pancreatin sample may be homogenized as needed so that a sample with the desired solvents content is obtained. 
     b) Further steps for the preparation of standardized pancreatin powder on a pilot plant and production scale include heating at the desired temperature until a solvents content of 1% by weight and a temperature of from 80° C. to 100° C. was reached in accordance with the starting requirements of the experiments described below (examples 1 to 11 below). 
     Further Processing of Pancreatin for Porcine Parvovirus Studies: 
     According to generally accepted principles in the scientific and pharmacological communities, pancreatin was spiked with added porcine parvovirus in order to establish proof of principle. The spiking was conducted according to the guideline CPMP/BWP/268/95. 
     After performing the standard drying of the production process (see above) on pancreatin, the pancreatin powder was cooled down and re-suspended in water (resulting in a 40% suspension in order to obtain a homogeneous distribution of the spiked virus within the pancreatin powder). The pancreatin was then spiked with a highly concentrated porcine parvovirus suspension in cell culture medium in a ratio 9:1 (pancreatin suspension: virus suspension). The resulting suspension was then lyophilized and subsequently heated at a temperature of from 80° C. to 100° C. until a solvents content of 1% and 3% by weight, respectively, was reached in accordance with the starting requirements of the experiments described below (examples 12 to 20 as below). 
     Example 1 
     48 kg of standardized pancreatin with a solvents content of 1% was subsequently heated at 80° C. for a period of 30 hours. The lipase activity was determined after 0, 2, 4, 6, 12, 15, 18, 21, 24 and 30 hours. The results of this experiment are shown in table 1 and in  FIG. 1 . 
     Example 2 
     48 kg of standardized pancreatin with a solvents content of 1% was subsequently heated at 85° C. for a period of 30 hours. The lipase activity was determined after 0, 6, 12, 15, 18, 21, 24 and 30 hours. The results of this experiment are shown in table 1 and in  FIG. 1 . 
     Example 3 
     48 kg of standardized pancreatin with a solvents content of 1% was subsequently heated at 90° C. for a period of 30 hours. The lipase activity was determined after 0, 6, 12, 15, 18, 21, 24 and 30 hours. The results of this experiment are shown in table 1 and in  FIG. 1 . 
     Example 4 
     48 kg of standardized pancreatin with a solvents content of 1% was subsequently heated at 95° C. for a period of 30 hours. The lipase activity was determined after 0, 6, 12, 15, 18, 21, 24 and 30 hours. The results of this experiment are shown in table 1 and in  FIG. 1 . 
     Example 5 
     48 kg of standardized pancreatin with a solvents content of 1% was subsequently heated at 100° C. for a period of 30 hours. The lipase activity was determined after 0, 6, 12, 15, 18, 21 and 24 hours. The results of this experiment are shown in table 1 and in  FIG. 1 . 
     Example 6 
     1.5 g of standardized pancreatin with a solvents content of 3% was subsequently heated at 90° C. for a period of 48 hours. The lipase activity was determined after 0, 2, 4, 8, 6, 15, 24 and 48 hours. The results of this experiment are shown in table 2 and in  FIG. 2 . 
     Example 7 
     1.5 g of standardized pancreatin with a solvents content of 3% was subsequently heated at 95° C. for a period of 48 hours. The lipase activity was determined after 0, 2, 4, 8, 6, 15, 24 and 48 hours. The results of this experiment are shown in table 2 and in  FIG. 2 . 
     Example 8 
     1.5 g of standardized pancreatin with a solvents content of 3% was subsequently heated at 80° C. for a period of 3.0 hours. The lipase activity was determined after 0.5, 1.0 and 3.0 hours. The results of this experiment are shown in table 3 and in  FIG. 3 . 
     Example 9 
     1.5 g of standardized pancreatin with a solvents content of 6% was subsequently heated at 80° C. for a period of 3.0 hours. The lipase activity was determined after 0.5, 1.0 and 3.0 hours. The results of this experiment are shown in table 3 and in  FIG. 3 . 
     Example 10 
     1.5 g of standardized pancreatin with a solvents content of 9% was subsequently heated at 80° C. for a period of 3.0 hours. The lipase activity was determined after 0.5, 1.0 and 3.0 hours. The results of this experiment are shown in table 3 and in  FIG. 3 . 
     Example 11 
     1.5 g of standardized pancreatin with a solvents content of 12% was subsequently heated at 80° C. for a period of 3.0 hours. The lipase activity was determined after 0.5, 1.0 and 3.0 hours. The results of this experiment are shown in table 3 and in  FIG. 3 . 
     Example 12 
     1.5 g of porcine parvovirus-spiked pancreatin with a solvents content of 1% was subsequently heated at 80° C. for a period of 30 hours. The virus concentration was determined after 6, 12, 15, 18, 21, 24 and 30 hours. The results of this experiment are shown in tables 4 and 5 as well as in  FIG. 4 . 
     Example 13 
     1.5 g of porcine parvovirus-spiked pancreatin with a solvents content of 1% was subsequently heated at 85° C. for a period of 30 hours. The virus concentration was determined after 6, 12, 15, 18, 21, 24 and 30 hours. The results of this experiment are shown in tables 4, 4a, and 5 as well as in  FIG. 4 . 
     Example 14 
     1.5 g of porcine parvovirus-spiked pancreatin with a solvents content of 1% was subsequently heated at 90° C. for a period of 30 hours. The virus concentration was determined after 6, 12, 15, 18, 21, 24 and 30 hours. The results of this experiment are shown in tables 4 and 5 as well as in  FIG. 4 . 
     Example 15 
     1.5 g of porcine parvovirus-spiked pancreatin with a solvents content of 1% was subsequently heated at 95° C. for a period of 30 hours. The virus concentration was determined after 6, 12, 15, 18, 21, 24 and 30 hours. The results of this experiment are shown in tables 4 and 5 as well as in  FIG. 4 . 
     Example 16 
     1.5 g of porcine parvovirus-spiked pancreatin with a solvents content of 1% was subsequently heated at 100° C. for a period of 30 hours. The virus concentration was determined after 6, 12, 15, 18, 21, 24 and 30 hours. The results of this experiment are shown in tables 4 and 5 as well as in  FIG. 4 . 
     Example 17 
     1.5 g of porcine parvovirus-spiked pancreatin with a solvents content of 1% was subsequently heated at 90° C. for a period of 12 hours. The virus concentration was determined after 3, 6 and 12 hours. The results of this experiment are shown in tables 6 and 7 as well as in  FIG. 5 . 
     Example 18 
     1.5 g of porcine parvovirus-spiked pancreatin with a solvents content of 3% was subsequently heated at 90° C. for a period of 12 hours. The virus concentration was determined after 3, 6 and 12 hours. The results of this experiment are shown in tables 6 and 7 as well as in  FIG. 5 . 
     Example 19 
     1.5 g of porcine parvovirus-spiked pancreatin with a solvents content of 1% was subsequently heated at 95° C. for a period of 12 hours. The virus concentration was determined after 3, 6 and 12 hours. The results of this experiment are shown in tables 6 and 7 as well as in  FIG. 5 . 
     Example 20 
     1.5 g of porcine parvovirus-spiked pancreatin with a solvents content of 3% was subsequently heated at 95° C. for a period of 12 hours. The virus concentration was determined after 3, 6 and 12 hours. The results of this experiment are shown in tables 6 and 7 as well as in  FIG. 5 . 
     Example 21 
     Pharmaceutical Composition Comprising Pancreatin 
     A composition comprising the pancreatin obtained by the process described herein is obtained as follows: 10 kg of pancreatin obtained by the process of example 2 is mixed with 2.5 kg of ethylene glycol 4000 and 1.5 kg of propan-2-ol to give a mixture which was then extruded in a known manner in an extruding press. Pancreatin micropellets are prepared as disclosed in EP 0 583 726 and can be further packed into capsules or sachets. 
     Example 22 
     Pancreatin Micopellets Coated with a Gastric Acid Resistant Coating 
     The pancreatin micropellet cores obtained by example 21 can be provided with a gastric acid resistant coating. For example, the pancreatin micropellet cores can be coated with gastric-juice-resistant film-forming agents such as, e.g., hydroxypropylmethylcellulose acetate succinate (=HPMCAS), hydroxypropylmethylcellulose phthalate (=HPMCP), cellulose acetate phthalate (=CAP) or polyvinyl acetate phthalate (=PVAP). Copolymers known as film-forming agents such as, for example, methacrylic acid/methyl methacrylate copolymers or methacrylic acid/ethyl acrylate copolymers, can also be used. The film-forming agents can be applied to the pancreatin micropellet cores using various film-coating apparatus, e.g. coaters, in the customary use forms, e.g. as organic solutions or organic or aqueous dispersions, optionally with addition of a conventional plasticizer. The resulting gastric acid-resistant film-coated pancreatin micropellets are distinguished by a high bulk density, for example in the range from 0.6 g/ml to 0.85 g/ml, which makes it possible to increase the filling weight per capsule and thus the active compound content of each capsule. Further experimental details on the process for preparing the gastric acid-resistant film-coated pancreatin micropellets are disclosed in EP 0 583 726. 
     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of individual numerical values are stated as approximations as though the values were preceded by the word “about” or “approximately.” Similarly, the numerical values in the various ranges specified in this application, unless expressly indicated otherwise, are stated as approximations as though the minimum and maximum values within the stated ranges were both preceded by the word “about” or “approximately.” In this manner, variations above and below the stated ranges can be used to achieve substantially the same results as values within the ranges. As used herein, the terms “about” and “approximately” when referring to a numerical value shall have their plain and ordinary meanings to a person of ordinary skill in the art to which the particular subject matter is most closely related or the art relevant to the range or element at issue. The amount of broadening from the strict numerical boundary depends upon many factors. For example, some of the factors which may be considered include the criticality of the element and/or the effect a given amount of variation will have on the performance of the claimed subject matter, as well as other considerations known to those of skill in the art. As used herein, the use of differing amounts of significant digits for different numerical values is not meant to limit how the use of the words “about” or “approximately” will serve to broaden a particular numerical value. Thus, as a general matter, “about” or “approximately” broaden the numerical value. Also, the disclosure of ranges is intended as a continuous range including every value between the minimum and maximum values plus the broadening of the range afforded by the use of the term “about” or “approximately.” Thus, recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it there individually recited herein. 
     Use of the phrase ‘the invention’ or ‘the present invention’ is not meant to limit the claims in any manner and no conclusion should be drawn that any description or argument associated with a particular use of the phrase ‘the invention’ or ‘the present invention’ applies to each and every claim. The use of the phrase ‘the invention’ or ‘the present invention’ has been used solely for linguistic or grammatical convenience and not to effect a limitation of any nature on any of the claims. 
     Alternative embodiments of the claimed invention are described herein, including the best mode known to the inventors for carrying out the claimed invention. Of these, variations of the disclosed embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing disclosure. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the claimed invention to be practiced otherwise than as specifically described herein. Accordingly, the claimed invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the claimed invention unless otherwise indicated herein or otherwise clearly contradicted by context. 
     It is to be understood that any ranges, ratios and ranges of ratios that can be formed by, or derived from, any of the data disclosed herein represent further embodiments of the present disclosure and are included as part of the disclosure as though they were explicitly set forth. This includes ranges that can be formed that do or do not include a finite upper and/or lower boundary. Accordingly, a person of ordinary skill in the art most closely related to a particular range, ratio or range of ratios will appreciate that such values are unambiguously derivable from the data presented herein. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of this disclosure (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., such as, preferred, preferably) provided herein, is intended merely to further illustrate the content of the disclosure and does not pose a limitation on the scope of the claims. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the claimed invention.