when capsules including the formulations described herein are ingested and enter the stomach , an impervious alginic acid gel forms as the capsule material dissolves and stomach acid reacts with the monovalent alginate salts that are proximal to the inner wall of the capsule material . the capsule material acts as a mold that allows a structured gel to form . this gel of alginic acid is insoluble , semi - rigid and relatively strong and acts to contain the majority of the digestive enzymes in a protected state as long as they remain in an acidic environment . depending on the motility within the stomach , composition of food contained in the stomach , water content , and other factors , the alginic acid gel may or may not stay intact as a cylindrical structure but may fragment . such fragments have inner structure that still confers significant protection until reaching the small intestine , where they dissolve , as the insoluble alginic acid gel converts back to soluble monovalent alginate , and releases the enzymes . one can also dry the monovalent alginates prior to use so they do not contribute moisture in the formulation . moisture can be destabilizing to dry enzymes and result in decreased shelf - life . in addition , decreased moisture contributes to more efficient formation of the protective alginic acid gel layer rendering it more rigid . typically , commercially available alginates have moistures in the range of 8 - 15 %, and are generally more suitable if dried to below 6 % moisture . drying must not denature the alginate polymeric structure , needed for forming the protective alginic acid gel . low temperature vacuum drying or infrared convection drying are generally suitable methods for drying the monovalent alginates , as are other methods that do not result in their denaturation . a suitable vacuum oven for drying is lab - line model no . 3620 from lab - line instruments , inc ., melrose park , ill . typical drying parameters are 60 - 70 ° c . for 12 - 18 hours at a vacuum of 27 - 28 inches of mercury , or until the final moisture content is equal to or less than 6 %. the amount of monovalent alginate required to adequately protect dry enzymes in formulations of the present invention ranges from 10 - 90 % of the weight of the formulation , with a preferred range from 20 - 40 % of the formulation . suitable commercial monovalent alginates for use in the present invention are algin - 900 ( tic gums ) and keltone hv ( isp ). commercial alginates are prepared from different seaweed sources and vary in their ratio of mannuronic acid to guluronic acid ( m : g ratio ). alginates prepared from giant kelp , macrocystis pyrifera , have high m values while alginates produced from laminaria hyperborean have high g values . g type alginates are preferred since they produce a stronger alginic acid gel than the m alginates ; but both alginate types are suitable for the formulations described herein . the amount of dry digestive enzymes used depends on the strength or activity of each enzyme that is required in the formulation , but will typically range from 10 - 90 % of the formulation . single digestive enzymes or blends of different enzymes can be used in the formulations . enzymes known to be particularly sensitive to stomach acid , e . g ., enzymes nattokinase and serrapeptase , can be effectively protected by the formulations herein . the following list of commercial enzymes represent examples of some of the digestive enzymes suitable for the formulation : typical enzyme origin activity alpha galactosidase aspergillus niger 15 , 000 galu / g amyloglucosidase aspergillus niger 1 , 000 ag / g bacterial alpha bacillus subtilis 300 , 000 bau / g amylase beta glucanase trichoderma 3 , 000 bgu / g longibrachiatum cellulase trichoderma 150 , 000 cu / g longibrachiatum cellulase an aspergillus niger 50 , 000 cu / g fungal alpha amylase aspergillus oryzae 100 , 000 skb / g fungal lactase aspergillus oryzae 100 , 000 alu / g yeast lactase kluyveromyces lactis hemicellulase aspergillus niger 400 , 000 hcu / g invertase saccharomyces 200 , 000 summer cerevisiae u / g pectinase aspergillus niger 500 , 000 ajdu / g xylanase trichoderma 150 , 000 xu / g longibrachiatum bromelain protease ananas comosus 2 , 000 gdu / g fungal protease aspergillus oryzae 400 , 000 hu / g neutral protease bacillus subtilis 2 , 000 , 000 pc / g papain protease carica papaya 800 tu / mg peptidase aspergillus oryzae 500 lap / g lipase rhizopus oryzae 150 , 000 fip / g lipase candida rugosa 200 , 000 fip / g lipase an aspergillus niger 20 , 000 fip / g phytase aspergillus niger 1 , 500 u / g pancreatin hog or bovine pancreas mixed enzymes the above enzymes can be obtained from bio - cat , inc ., troy , va ., usa . if the formulations require inert excipient ingredients to complete the formulation , there are a variety of inert , dry , pharmaceutical or food grade products that can be used . examples are microcrystalline cellulose , silica , resistant starches and prebiotic carbohydrates such as inulin . while many types of inert excipients can be used , preferred excipients would be those with very low moisture contents . avicel ph112 brand microcrystalline cellulose from fmc is an example of an excipient with a total moisture content below about 2 %. syloid 63 fp from wr grace is an example of a silica based excipient , with a moisture content less than 1 %, which can be used with avicell ph112 in the formulations . when it is not required to use any microcrystalline cellulose or other bulk excipient in a formulation , such as might be the case when high activity levels of enzymes are desired , it is still recommended that a silica ingredient such as syloid 63 fp be added at 1 - 2 % of the formulation to improve the flow characteristics of the powder , to thereby enhance capsule filling . furthermore , it may also be required under commercial capsule filling conditions to utilize magnesium stearate at 1 - 2 % in the formulations to enhance lubrication of the powder blend , for more efficient capsule filling . packaging of capsules filled with formulations of the present invention should be carried out in amber glass bottles or hermetically sealed foil packages of high quality to insure maximum shelf - life of the finished product . addition of moisture and oxygen absorption packets inside the bottles or foil packets helps to maximize shelf - life . chelating agents such as edta , sodium hexametaphosphate , tetrasodium pyrophosphate or sodium citrate can be co - administered with the formulations to inhibit premature conversion of soluble alginates in the duodenum to insoluble divalent alginates , that may delay or complicate the release of the enzymes . preferably these chelating agents , which effectively bind divalent ions such as calcium and magnesium , should be consumed separately in capsule or tablet form , prior to consuming capsules containing the enzyme formulations . any of the above mentioned chelating agents when consumed at levels of 250 - 1500 mg per dose would sufficiently reduce the formation of divalent alginates . the formulations can be prepared according to the following manufacturing steps , with more details and conditions set forth in the examples : 1 . prepare dry commercial monovalent alginate salts , preferably sodium alginate , by low temperature vacuum oven drying or infrared convection drying that reduces the moisture content below 6 %, utilizing conditions that do not denature the polymeric structure of the alginate . 2 . mix the dry alginate with high quality dry digestive enzymes in a double cone or paddle / ribbon type mixer under conditions of low humidity , e . g ., humidity below 25 %. the preferred amount of alginate to use is in the range of 15 - 40 % of the weight of the total blend , excipients and / or buffers can be added prior to mixing the alginate - enzyme mixture so that only one mixing step is required . mixing times should be in the range of 5 - 20 minutes to avoid over - mixing which can otherwise result in un - mixing of the blend . 3 . the blended product should be promptly filled into capsules after blending , such as hpmc , cellulose or gelatin capsules . this should also be done under conditions of low humidity . running the blended powder through a 12 - 14 mesh screen after blending but prior to capsule filling may facilitate the capsule filling process . 4 . filled capsules should be packaged in air tight containers such as amber glass bottles or foil packages containing moisture and oxygen absorption packets . 1 . keltone hv brand sodium alginate from isp , inc . was dried in a lab - line vacuum oven to a moisture content of 5 . 5 %, the oven temperature was not allowed to exceed 70 ° c . drying time was 18 hours at 28 ″ of vacuum . 2 . a blend of commercial digestive enzymes ( ec - 1a obtained from bio - cat , inc . of troy , va .) contained the following enzymes : bromelain 800 gdu / g , papain 237 tu / mg , lipase 33 , 600 fip / g , fungal protease 32 , 000 hu / g . 3 . avicel ph112 brand microcrystalline cellulose was obtained from fmc , syloid 63 fp brand silica from w . r . grace and glycerol phosphate disodium salt from sigma - aldrich . 4 . the following formulation was prepared from the above ingredients in a lab scale stainless steel paddle mixer : 500 g ec - 1a enzyme blend + 260 g avicel ph112 + 200 g dry keltone hv + 20 g syloid 63 + 20 g disodium glycerol phosphate . the mixture was blended for 10 minutes at 60 rpm and then hand filled into size “ 0 ” hpmc vcaps from capsugel , to a net weight of 400 mg / capsule . 5 . the capsules were then tested for enzyme activity with no immersion ( control 1 ) and after immersion ( test 1 ) in simulated gastric juice ( composition : 1 liter distilled water + 2 g nacl + 7 . 0 ml 37 % hcl , ph = 1 . 6 ). immersion in simulated gastric juice was carried out with the capsules submersed in a beaker of the juice , 10 capsules total , held under by a stainless steel screen , while stirring the juice magnetically at 90 rpm for 60 minutes at 37 ° c . the ph in the beaker was 1 . 7 during the test . after the 60 minute period , the remaining capsules ( or fragments ) were dissolved by raising the ph of the beaker contents to 7 . 5 with a 10 % naoh solution followed by assaying for enzyme activity ( four separate assays ). for capsules that were not immersed in gastric juice , they ( contents of 10 capsules ) were dissolved directly in 0 . 2 % saline at ph 7 . 5 and assayed by the same four enzyme assays . results 1a : enzyme activities on capsules with no immersion at ph 1 . 7 ( control 1 ): results 1b : enzyme activities on capsules after immersion at ph 1 . 7 ( test 1 ):* conclusion : the % loss in enzyme activity , average of 4 tests , test vs control , was 8 . 75 %. * note : the enzyme tests used in example i were not the tests used by the supplier ( bio - cat , inc .) of the ec - 1a enzyme blend with the exception of the fip test for lipase which was the same ; the supplier did not measure the enzyme activities once the blend had been produced but rather , measured the individual enzyme activity prior to making the blend . the tests used in our example i were selected because they were better able to show proteolytic activity by three different assay techniques on enzymes in the blend . the same procedure was followed as for example i except the sodium alginate in step 4 ( keltone hv ) was replaced by additional avicel ph112 , thus producing a formulation without acid protecting monovalent alginate . the formulation had the following composition : 500 g ec - 1a enzyme blend + 460 g avicel ph112 + 20 g syloid 63 + 20 g disodium glycerol phosphate . the mixture was blended for 10 minutes at 60 rpm and then hand filled into size “ 0 ” hpmc vcaps from capsugel to a net weight of 400 mg / capsule . the capsules were tested for enzyme activity after immersion ( test 2 ) in simulated gastric juice ( composition : 1 liter distilled water + 2 g nacl + 7 . 0 ml 37 % hcl , ph = 1 . 6 ). immersion in simulated gastric juice was carried out with the capsules submersed in a beaker of the juice , 10 capsules total , held under by a stainless steel screen , while stirring the juice magnetically at 90 rpm for 60 minutes at 37 c . the ph in the beaker was 1 . 65 during the test . after the 60 minute period , the remaining capsules ( or fragments ) were dissolved by raising the ph of the beaker contents to 7 . 5 with a 10 % naoh solution followed by assaying for enzyme activity ( four separate assays ). results 2a : enzyme activities on capsules after immersion at ph 1 . 65 ( test 2 ): total protease by hut test = 66 , 424 hut / g ( 60 % loss vs control 1 — see example 1 ). total protease by pu ( papain units ) test = 4 , 979 , 250 pu / g ( 55 % loss vs control 1 ). total protease by pc ( bacterial protease units )= 72 , 554 pc / g ( 68 % loss vs control 1 ). lipase by fip ( fcc lipase units )= 2 , 282 fip / g ( 82 % loss vs control 1 ). conclusion : the % loss in enzyme activity , average of 4 tests , test 2 vs control 1 , was 66 . 25 %. this indicates that the protection conferred by the sodium alginate in example i is significant . a digestive enzyme formulation employing the discoveries of the present invention was prepared by the following technique : 1 . keltone hv brand sodium alginate from isp , inc . was dried in a lab - line vacuum oven to a moisture content of 5 . 0 %, the oven temperature was not allowed to exceed 70 c . drying time was 19 hours at 28 ″ of vacuum . 2 . a blend of commercial digestive enzymes referred to as ec - 2b was obtained from bio - cat , inc . of troy , va . containing the following enzymes : fungal alpha amylase 40 , 000 skb / g , cellulase 24 , 000 cu / g , hemicellulase 51 , 200 hcu / g , pectinase 60 , 000 ajdu / g , alpha galactosidase 1 , 320 galu / g , glucoamylase 48 ag / g , fungal lactase 4 , 000 alu / g , and invertase 3 , 200 summer u / g . 3 . avicel ph112 brand microcrystalline cellulose was obtained from fmc , syloid 63 fp brand silica from w . r . grace and glycerol phosphate disodium salt from sigma - aldrich . 4 . the following formulation was prepared from the above ingredients in a lab scale stainless steel paddle mixer : 500 g ec - 2b enzyme blend + 160 g avicel ph112 + 300 g dry keltone hv + 20 g syloid 63 + 20 g disodium glycerol phosphate . the mixture was blended for 10 minutes at 60 rpm and then hand filled into size “ 0 ” hpmc vcaps from capsugel to a net weight of 410 mg / capsule . 5 . the capsules were then tested for enzyme activity with no immersion ( control 2 ) and after immersion ( test 3 ) in simulated gastric juice ( composition : 1 liter distilled water + 2 g nacl + 7 . 0 ml 37 % hcl , ph = 1 . 6 ). immersion in simulated gastric juice was carried out with the capsules submersed in a beaker of the juice , 10 capsules total , held under by a stainless steel screen , while stirring the juice magnetically at 90 rpm for 60 minutes at 37 c . the ph in the beaker was 1 . 75 during the test . after the 60 minute period , the remaining capsules ( or fragments ) were dissolved by raising the ph of the beaker contents to 7 . 5 with a 10 % naoh solution followed by assaying for enzyme activity ( four separate assays ). for capsules that were not immersed in gastric juice they ( contents of 10 capsules ) were dissolved directly in 0 . 2 % saline at ph 7 . 5 and assayed by the same four enzyme assays . only four of the eight enzymes in the blend ec - 2b were assayed due to problems encountered with assaying multiple enzymes in a blend . results 3a : enzyme activities on capsules with no immersion at ph 1 . 7 ( control 2 ): results 3b : enzyme activities on capsules after immersion at ph 1 . 7 ( test 3 ): total alpha galactosidase in galu / g , fcc method = 590 galu / g ( 3 . 3 % loss vs cont . 2 ) total cellulase in cu / g , fcc method = 11 , 000 cu / g ( 1 . 8 % loss vs control 2 ). total hemicellulase in hcu / g , fcc method = 23 , 100 hcu / g ( 2 . 1 % loss vs control 2 ). total lactase in alu / g by fcc method = 1 , 400 alu / g ( 17 . 6 % loss vs control 2 ). conclusion : with the exception of lactase which lost 17 . 6 %, the losses of the other three enzymes were negligible . the 30 % sodium alginate used in the formulation for this example iii provided significant acid protection . the same procedure was followed as for example iii except the sodium alginate in step 4 ( keltone hv ) was replaced by additional avicel ph112 , thus producing a formula without the acid - protecting alginate . the formulation had the following composition : 500 g ec - 2b enzyme blend + 460 g avicel ph112 + 20 g syloid 63 + 20 g disodium glycerol phosphate . the mixture was blended for 10 minutes at 60 rpm and then hand filled into size “ 0 ” hpmc vcaps from capsugel to a net weight of 390 mg / capsule . the capsules were tested for enzyme activity after immersion ( test 4 ) in simulated gastric juice ( composition : 1 liter distilled water + 2 g nacl + 7 . 0 ml 37 % hcl , ph = 1 . 6 ). the capsules were submersed in a beaker of the juice , 10 capsules total , held under by a stainless steel screen , while stirring the juice magnetically at 90 rpm for 60 minutes at 37 ° c ., the ph was 1 . 7 . after the 60 minute period , the remaining capsules ( or fragments ) were dissolved by raising the ph of the beaker contents to 7 . 5 with a 10 % naoh solution . thereafter , four separate assays were conducted for enzyme activity . enzyme activities on capsules after immersion at ph 1 . 7 ( test 4 ): total alpha galactosidase in galu / g , fcc method = 190 galu / g ( 69 % loss vs control 2 ); total cellulase in cu / g , fcc method = 8 , 200 cu / g ( 25 . 4 % loss vs control 2 ). total hemicellulase in hcu / g , fcc method = 17 , 100 hcu / g ( 25 . 9 % loss vs control 2 ). total lactase in alu / g , fcc method = 250 alu / g ( 82 % loss vs . control 2 ). results : the percentage loss in enzyme activity , average of 4 tests , test 4 vs control 2 , was 50 . 6 %— a significant loss compared to the relatively small losses reported in example 3 , indicating that four ( of 8 total ) enzymes present in the ec - 2b blend are negatively affected by immersion in ph 1 . 7 simulated gastric juice , for one hour when not protected by sodium alginate . it should be understood that the examples , terms and expressions herein are exemplary only and not limiting , and that the scope of the invention is defined only in the claims which follow , and includes all equivalents of the claimed subject matter .
disclosed are alginate formulations that help protect digestive enzymes in the formulations from denaturation during passage through the acidic stomach environment , and from other sources , following ingestion . the formulation changes consistency to permit release of the enzymes in the less - acidic gut . they contain monovalent alginate salts but are designed to not include significant quantities of compounds which would generate divalent ions and thereby convert the monovalent alginate to a divalent alginate when exposed to aqueous solution . a buffering agent that does not react with the digestive enzymes or the monovalent alginate , and which does not generate divalent ions on exposure to aqueous solution , can be included . a chelating agent which binds divalent ions may be administered with the formulation . additionally , the formulation may be admixed with inert excipients suitable for oral delivery . it is preferable that the ingredients are dried before formulation .