CA2160692A1 - Modified hydrolyzed vegetable protein microspheres and methods for preparation and use thereof - Google Patents
Modified hydrolyzed vegetable protein microspheres and methods for preparation and use thereofInfo
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- CA2160692A1 CA2160692A1 CA002160692A CA2160692A CA2160692A1 CA 2160692 A1 CA2160692 A1 CA 2160692A1 CA 002160692 A CA002160692 A CA 002160692A CA 2160692 A CA2160692 A CA 2160692A CA 2160692 A1 CA2160692 A1 CA 2160692A1
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K9/00—Medicinal preparations characterised by special physical form
- A61K9/14—Particulate form, e.g. powders, Processes for size reducing of pure drugs or the resulting products, Pure drug nanoparticles
- A61K9/16—Agglomerates; Granulates; Microbeadlets ; Microspheres; Pellets; Solid products obtained by spray drying, spray freeze drying, spray congealing,(multiple) emulsion solvent evaporation or extraction
- A61K9/1605—Excipients; Inactive ingredients
- A61K9/1629—Organic macromolecular compounds
- A61K9/1658—Proteins, e.g. albumin, gelatin
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- Life Sciences & Earth Sciences (AREA)
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- Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
Abstract
Modified hydrolyzed vegetable protein microspheres and methods for their prepa-ration and use as oral delivery systems for pharmaceutical agents are described. Figure I illustrates levels of glucose detected in rat serum taken from rats orally administered mi-crosphere encapsulated insulin or raw (unen-capsulated) insulin as described in example 4. Figure 2 illustrates rat serum calcium lev-els after oral administration of calcitonin and calcitonin encapsulated in the vegetable pro tein microsphere of the present invention as described in example 5. Figure 3 illustrates an HPLC trace of the hydrolyzed vegetable protein before modification. Figure 4 illus-trates the change in the hydrolyzed vegetable protein after modification with benzene sul-fonyl chloride in an HPLC trace.
Description
W094/~702 PCT~S94/04561 .
MODIFIED HYDROLYZED VEGETABLE PROTEIN MICROSPHERES
AND METHODS FOR PREPARATION AND USE THEREOF
This is a continuation-in-part of U.S. Patent applica-tion Serial No. 08/051,739, filed April 22, 1993, which is a continuation-in-part of U.S. Patent application Serial No.
07/995,508, filed December 21, 1992. This invention relates to modified hydrolyzed vegetable proteins and microspheres made from them. The microspheres releasably encapsulate active agents and are suitable for oral ~mlnlstration to m~mm~ls. Methods for the preparation of such microspheres are also disclosed.
Backqround of the Invention The available means for delivering pharmaceutical and therapeutic agents to m~mm~ls often are severely limited by chemical or physical barriers or both, which are imposed by the body. For example, oral delivery of many biologically-active agents would be the route of choice if not for the presence of chemical and physicochemical barriers such as extreme pH in the gut, exposure to powerful digestive enzymes, and impermeability of gastrointestinal membranes to the active ingredient. Among the numerous pharmacological agents which are known to be unsuitable for oral administration are biologically active peptides and proteins, such as insulin. These agents are rapidly destroyed in the gut by acid hydrolysis and/or by proteolytic enzymes.
MODIFIED HYDROLYZED VEGETABLE PROTEIN MICROSPHERES
AND METHODS FOR PREPARATION AND USE THEREOF
This is a continuation-in-part of U.S. Patent applica-tion Serial No. 08/051,739, filed April 22, 1993, which is a continuation-in-part of U.S. Patent application Serial No.
07/995,508, filed December 21, 1992. This invention relates to modified hydrolyzed vegetable proteins and microspheres made from them. The microspheres releasably encapsulate active agents and are suitable for oral ~mlnlstration to m~mm~ls. Methods for the preparation of such microspheres are also disclosed.
Backqround of the Invention The available means for delivering pharmaceutical and therapeutic agents to m~mm~ls often are severely limited by chemical or physical barriers or both, which are imposed by the body. For example, oral delivery of many biologically-active agents would be the route of choice if not for the presence of chemical and physicochemical barriers such as extreme pH in the gut, exposure to powerful digestive enzymes, and impermeability of gastrointestinal membranes to the active ingredient. Among the numerous pharmacological agents which are known to be unsuitable for oral administration are biologically active peptides and proteins, such as insulin. These agents are rapidly destroyed in the gut by acid hydrolysis and/or by proteolytic enzymes.
~,iGo692 2 Much research has been devoted to developing effective oral drug delivery methods and systems for these vulnerable pharmacological agents. The proposed solutions ha~re included:
(a) co-administration of adjuvants (such as resorci-5 nols and non-ionic surfactants polyoxyethylene oleyl ether and n-hexadecyl polyethylene ether to increase the permeability of the intestinal walls; and ~
(b) co-administration of enzyr~tic inhibitors, such as pancreatic trypsin inhibitor, diisopropylfluorophosphate (DFF) 10 and trasylol to avoid enzymatic degradation.
The use of such substances, in drug delivery systems, is limited however either because of their:
(a) inherent toxicity when employed in effective amounts; or (b) failure to protect the activeingredient or promote its absorption; or (c) adverse interaction with the drug.
Liposomes as drug delivery systems have also been described. They provide a layer of lipid around the encapsulated 20 pharmacological agent. The use of liposomes containing heparin is disclosed in U.S. Patent No. 4,239,754 and several studies have been directed to the use of liposomes containing insulin;
e.g., Patel et al. (1976) FEBS Letters Vol. 62, page 60 and Hashimoto et al. (1979) Endocrinol. Japan, Vol. 26, page 337.
25 The use of liposomes, however, is still in the development stage and there are continuing problems, including:
(a) poor stability;
(b) inadequate shelf life;
(c) limited to low MW (< 30,000) cargoes;
(d) difficulty in manufacturing;
(e) adverse interactions with cargoes.
More recently, artificial amino acid polymers or proteinoids, forming microspheres, have been described for encapsulating pharmaceuticals. For example, U.S. Patent No.
35 4,925,673 (the '673 patent), the disclosure of which is hereby WO94/7170~ 216 0 6 9 Z PCT~594104561 incorporated by reference in its entirety, describes such microsphere constructs as well as methods for their preparation and use. The microspheres of the '673 patent are useful for encapsulating a number of active agents, however there is a need in the art for microsphere carriers that can encapsulate a broader range of active agents such as lipophilic drugs.
Additionally, the method employed in the '673 patent for preparing proteinoids results in a complex mixture of high molecular weight (MW) (~ lO00 daltons) and low MW (~ lO00 daltons) peptide-like polymers which are difficult to separate.
Moreover, small amounts of the low MW microsphere-forming proteinoids are obtained. Thus, an improved method of preparing low molecular weight sphere-forming proteinoids is also desired.
Summary of the Invention The present invention relates to a modified hydrolyzed vegetable protein microsphere and to a method for preparation of such microspheres. The invention provides stable microspheres which are preparable from inexpensive hydrolyzed vegetable protein, e.g. soybean protein, and a simple and economical method for making such microsphere. Microspheres made according to the invention display improved stability and performance in deliver-ing biologically active materials to m~mm~l S.
According to the invention, modified hydrolyzed vegetable microspheres are prepared by dissolving hydrolyzed vegetable protein in an aqueous alkaline solution and adding a chemical modifier which reacts with free amine residues present in the hydrolyzed protein. The pH of the reaction mixture is then lowered until the modified vegetable protein precipitates out from the mixture. The recovered protein readily forms micro-spheres and can be used to encapsulate various cargoes such as pharmaceutical agents. The microspheres are non-toxic and can be orally or parenterally administered to m~mm~l S. Also contemplated by the present invention are dosage unit forms that include these compositions.
W094/~702 PCT~S94/04561 2l~O~92 Description of the Drawin~s Figure 1 illustrates levels of glucose detected in rat serum taken from rats orally administered microsphere encapsulat-ed insulin or raw (unencapsulated) insulin as described in Example 4. ~
Figure 2 illustrates rat seru~ calcium levels after oral administration of calcitonin and càlcitonin encapsulated in the vegetable protein microsphere of the present invention as described in Example 5.
Figure 3 illustrates an an HPLC trace of the hydrolyzed vegetable protein before modification.
Figure 4 illustrates the the change in the hydrolyzed vegetable protein after modification with benzene sulfonyl chloride in an HPLC trace.
Detailed Description of the In~ention All patents, patent applications, and literatures cited in the specification are hereby incorporated by reference in their entirety. In the case of inconsistencies, the present disclosure, including definitions, will prevail.
The modified vegetable protein microspheres of the present invention may be prepared by reacting a hydrolyzed vegetable protein with a chemical modifying agent which reacts with free amino residues present in the protein. The modified vegetable protein is then converted into microspheres which encapsulate active ingredients, e.g. drugs. A number of advantages are obt~;n~hle by the present invention which include (a) the use of readily available and inexpensive starting materials and (b) a cost-effective method for preparing and isolating microsphere-producing modified proteins. The overall modification process is simple to perform and is ~m~n~hle to industrial scale-up production.
The compositions of the subject invention are useful W094/~702 2 1 6 ~ ~ 9 ~ PCT~S94/04561 for ~ml n; stering biologically-active agents to any ~nlm~l s such as birds; m~mm~ls such as primates and particularly humans; and insects.
According to the method of the present invention, an acid or enzyme hydrolyzed vegetable protein is useful in practicing the invention. The vegetable protein generally contains titratable carboxylic acid groups (COOH) ranging between about 3 and about 8 milliequivalents/g, preferably between about 4 and about 6 milliequivalents/g, total free amino groups (NH2) ranging between about 3 and about 9 milliequivalents/g, prefera-bly ranging between about 4 and about 7 millie~uivalents/g NH2.
The molecular weight of the vegetable protein ranges between about l00 D and about 2000 D, preferably between about 200 and about 500 D.
Hydrolyzed vegetable protein is available from a variety of commercial sources. Non-limiting examples of such sources include Ajinomoto USA, Inc. (Teaneck, NJ 07666, USA);
Central Soya Co., Inc. (Fort Wayne, IN, USA); and Champlain Industries, Inc. (Clifton, NJ, USA) and additional companies listed in "Food Engineering Master", an annual publication of Chilton Co., Radnor, PA 19089, USA. A particularly pre~erred hydrolyzed vegetable protein in practicing this invention is available from Ajinomoto USA under the tradename AJI-EKI. This produc~ is an acid hydrolyzed li~uid soybean protein which is derived from defatted soybean meal.
If desired, a dried protein extract of the hydrolyzed vegetable protein solution may be used to prepare the modified vegetable protein of the invention. The dried protein extract is preparable by extracting the hydrolyzed vegetable solution with a suitable solvent, e.g., methanol, followed by evaporating the solvent extract.
The vegetable protein is then dissolved in aqueous alkaline solution of a metal hydroxide, e.g., sodium or potassium hydroxide, and heated at a temperature ranging between about 50C
W094/~702 PCT~S94/04561 2~6~ ~ 6 and about 70C, preferably between about 50C and about 60C, for a period ranging between about 10 minutes and about 40 minutes, preferably about 15 minutes. The amount of alkali employed per mmole of titratable NH2 in the vegetable protein generally ranges between about 2 and about 3 mmole, preferably between about 2.2 and about 2.5 mmole. The pH of the solution generally ranges between about 8 and about 13, preferably;~ranging between about 9 and about 10.
Thereafter, an amine modifying agent is then added to the reaction mixture while stirring. The amine modifying agents are compositions that can react with the free amino (NH2) residues present in the protein. Some non-limiting examples of amine modifying agents useful in practicing the present invention include sulfonating agents such as benzene sulfonyl chloride and acylating agents such as benzoyl chloride.
The amount of amine modifying agent in relation to the quantity of hydrolyzed vegetable protein employed is based on the equivalents of total free NH2 in the vegetable protein. Thus, between about 0.3 and about 1.2 equivalents of modifying agent are used for each molar equivalent of total NH2 groups in vegetable protein, and preferably between about 0.6 and about 1.0 equivalents of the modifying agent for each molar equivalent of total NH2 groups in the hydrolyzed vegetable protein.
In practicing the invention, the mixture of vegetable protein and modifying agent is maintained at a temperature generally ranging between about 50C and about 70C, preferably between about 60C and about 65C for a period ranging between about 2 and about 5 hours.
The reaction is quenched by adjusting the pH of the mixture with a suitable acid, e.g., concentrated hydrochloric acid, until the pH reaches between about 2 and about 3. The mixture separates on standing at room temperature to form an opaque upper layer and a dark viscous lower layer. The upper layer is discarded and modified vegetable protein is collected W094/~702 21 6 0 69 2 PCT~S94/04561 from the lower layer by filtration. The crude modified vegetable protein is then dissolved in water at a pH ranging between about 9 and about 13, preferably between about 11 and about 13.
Insoluble materials are removed by filtration and the filtrate is dried in vacuo. The yield of modified protein generally ranges between about 30 and about 60~, usually about 45~.
The modified vegetable protein of the present invention is soluble in alkaline aqueous solution (pH> 9.0); partially soluble in ethanol, n-butanol and 1:1 (v/v) toluene/ethanol solution and insoluble in neutral water. The titratable function-al groups remaining in the vegetable protein after modification are as follows: carboxylic acid groups (COOH) ranging between about 1.5 and about 3.5 milliequivalents/g, preferably about 2.3 milliequivalents/g, amino groups (NH2) ranging between about 0.3 and about 0.9 milliequivalents/g, preferably about 0.5 milliequi-valents/g. The molecular weight of the modified vegetable protein ranges between about 200 D and about 2000 D, preferably between about 200 D and about 500 D.
The modified vegetable protein of the present invention can be used immediately to microencapsulate an active pharmaco-logical agent or the protein can be concentrated or dried by conventional means and stored for future use.
The modified vegetable protein may be purified by fractionation on solid column supports such as alumina, using methanol/n-propanol mixtures as the mobile phase; reverse phase column supports using trifluoroacetic acid/acetonitrile mixtures as the mobile phase; and ion exchange chromatography using water as the mobile phase. When anion exchange chromatography is performed, a subsequent 0-500 mM sodium chloride gradient is employed. The modified vegetable protein may also be purified by extraction with a lower alcohol such as methanol, butanol, or isopropanol to remove low molecular weight cont~m~n~nts.
The following procedure may be employed to make microspheres from purified modified vegetable protein. Modified W094/~702 PCT~S94tO4561 6 9 ~
vegetable protein is dissolved in deionized water at a concentra-tion ranging between about 75 and about 200 mg/ml, preferably about 100 mg/ml at a temperature between about 25~C and about 600C, preferably about 400C. Particulate matter rPm~;n;ng in the solution may be removed by conventional means such as gravity filtration over filter paper.
Thereafter, the protein solution, maintained at a temperature of about 400C, is mixed 1.1 (V/V) with an aqueous acid solution (also at about 400C) having an acid concentration ranging between about 0.05 N and about 2 N, preferably about 1.7 N. The resulting mixture is further incubated at 400C for a period of time effective for microsphere formation as observed by light microscopy. In practicing this invention, the preferred order o~ addition is to add the protein solution to the agueous acid solutlon.
Suitable acids include any acid which does not (a) adversely effect the protein, e.g., chemical decomposition; (b) interfere with microsphere formation; (c) interfere with microsphere encapsulation of cargo; and (d) adversely interact with the cargo. Preferred acids for use in this invention include acetic acid, citric acid, hydrochloric acid, phosphoric acid, malic acid and maleic acid.
In practicing the invention, a microsphere stabilizing additive preferably incorporated into the aqueous acid solution or into the protein solution, prior to the microsphere formation process. The presence of such additives promotes the stability and dispersibility of the microspheres in solution.
The additives may be employed at a concentration ranging between about 0.1 and 5 ~ (W/V), preferably about 0.5 ~
(W/V). Suitable, but non-limiting, examples of microsphere stabilizing additives include gum acacia, gelatin, polyethylene glycol, and polylysine.
Under the above conditions, the carrier forms hollow or solid matrix type microspheres wherein the cargo is distributed in a carrier matrix or capsule type microspheres encapsulating W094l~702 21 6 0 6 9 2 PCT~S94/04561 liquid or solid cargo. If the carrier microspheres are formed in the presence of a soluble material, e.g., a pharmaceutical agent in the aforementioned aqueous acid solution, this material will be incorporated in the microspheres. In this way, one can incorporate pharmacologically active materials such as peptides, proteins, and polysaccharides as well as charged organic molecules, e.g., antimicrobial agents, which normally have poor bioavailability by the oral route. The amount of ph~rm~ceutical agent which may be incorporated in the microsphere is dependent on a number of factors which include the concentration of agent in the microsphere forming solution, as well as the affinity of the cargo for the carrier.
Under these conditions, the modified vegetable protein molecules form hollow microspheres of less than lO microns in diameter. If the protein microspheres are formed in the presence of a soluble material, e.g., a pharmaceutical agent in the aforementioned aqueous acid solution, this material will be encapsulated in the hollows of the microspheres and confined within the protein wall defined by the spherical structure. In this way, one can encapsulate pharmacologically active materials such as peptides, proteins, and polysaccharides as well as charged organic molecules, e.g., quinolones or antimicrobial agents, having poor bioavailability by the oral route. The amount of pharmaceutical agent which may be encapsulated by the microsphere is dependent on a number of factors which include the concentration of agent in the encapsulating solution, as well as the affinity of the cargo for the carrier.
Biologically-active agents suitable for use with carriers disclosed herein include, but are not limited to, peptides, and particularly small peptide hormones, which by themselves do not pass or only pass slowly through the gastro-intestinal mucosa and/or are susceptible to chemical cleavage by acids and enzymes in the gastro-intestinal tract; polysaccharides and particularly mixtures of mucopolysaccharides; carbohydrates;
lipids; or any combination thereof. Examples include, but are W094/~702 21~ ~ 6 9 ~ PCT~S94/04561 ~
not limited to, human growth hormone; bovine growth hormone;
growth hormone releasing hormone; interferons; interleukin-I;
insulin; heparin, and particularly low molecular weight heparin;
calcitonin; erythropoietin; atrial naturetic factor; antigens;
monoclonal antibodies; somatostati~i adrenocorticotropin;
gonadotropin releasing hormone; oxytocin; vasopressin; cromolyn sodium (sodium or disodium cromoglycate); vancomycin;
desferrioxamine (DFO); or any combination thereof.
Additionally the carriers of the present invention can be used to deliver other active agents such as pesticides and the like.
The amount of active agent in the composition typically is a pharmacologically or biologically effective amount.
However, the amount can be less than a ph~rm~cologically or biologically effective amount when the composition is used in a dosage unit form, such as a capsule, a tablet or a liquid, because the dosage unit form may contain a multiplicity of carrier/biologically-active agent compositions or may contain a divided pharmacologically or biologically effective amount. The total effective amounts will be administered by cumulative units containing in total pharmacologically or biologically active amounts of biologically-active agent.
Dosage unit forms can also include any of excipients;
diluents; disintegrants; lubricants; plasticizers; colorants; and dosing vehicles, including, but not limited to water, 1,2-propane diol, ethanol, olive oil, or any combination thereof.
The modified vegetable protein microspheres of the invention are pharmacologically harmless and do not alter the physiological and biological properties of the active agent.
Furthermore, the encapsulation process does not alter the pharmacological properties of the active agent. While any pharmacological agent can be encapsulated within the protein microspheres, it is particularly valuable for delivering chemical or biological agents which otherwise would be destroyed or rendered less effective by conditions encountered within the body W094/~702 2 ~ G 0 6 ~ 2 PCT~S94/04561 o~ the m~mm~l to which it is administered, before the microsphere reaches its target zone (i.e., the area in which the contents of the microsphere are to be released) and which are poorly absorbed in the gastrointestinal tract.
The protein microspheres of the invention are particu-larly useful for the oral administration of certain pharmacologi-cal agents, e.g., small peptide hormones, which, by themselves, pass slowly or not at all through the gastro-intestinal mucosa and/or are susceptible to chemical cleavage by acids and enzymes in the gastrointestinal tract. Non-limiting examples of such agents include human or bovine growth hormone, interferon and interleukin-II, calcitonin, atrial naturetic factor, antigens and monoclonal antibodies.
The particle size of the microsphere plays an important role in determ;nlng release of the active agent in the targeted area o~ the gastrointestinal tract. Microspheres having diameters between about ~ O.l microns and about lO microns, preferably between about 5.0 microns and about O.l microns, and encapsulating active agents are sufficiently small to effectively release the active agent at the targeted area within the gastrointestinal tract. Small microspheres can also be ~m;n;s-tered parenterally by being suspended in an appropriate carrier fluid (e.g., isotonic saline) and injected into the circulatory system or subcutaneously. The mode of administration selected will, of course, vary, depending upon the requirement o~ the active agent being administered. Large protein microspheres (>lO
microns) tend to be less effective as oral delivery systems.
The size of the microspheres formed by contacting modified vegetable protein with water or an aqueous solution containing active agents can be controlled by manipulating a variety of physical or chemical parameters, such as the pH, osmolarity or ionic strength of the encapsulating solution, and by the choice of acid used in the encapsulating process.
The vegetable protein-derived microspheres of the present invention are suitable for oral administration of peptide W094/~702 PCT~S94104561 21~0~92 ~
~ 12 hormones, e.g., insulin, and polysaccharides, e.y., heparin, which otherwise would be quickly destroyed in the stomach. They also are suitable ~or protecting the stomach ~rom gastric irritants, such as aspirin and NSAID~S~. When such aspirin containing microspheres are orally ~m; n~ stered, they pass through the gastrointestinal mucosa and release the aspirin far more rapidly than conventional enterically coated aspirin, which first must traverse the stomach and then must enter the blood-stream from the intestine after the enteric coating has dis-solved.
The microspheres of the invention may be orallyadministered alone as solids in the form of tablets, pellets, capsules, and granulates suitable for suspension in liquids such as water or edible oils. Similarly, the microspheres can be formulated into a composition containing one or more physiologi-cally compatible carriers or excipients, and which can be administered via the oral route. These compositions may contain conventional ingredients such as gelatin, polyvinylpyrrolidone and fillers such as starch and methyl cellulose. Alternatively, small microspheres (size less than lO ~m) can be administered via the parenteral route.
The following examples are illustrative of the invention but are not intended to limit the scope of the lnvention.
Exam~le l: Modification of Soybean protein with benzenesulfonyl chloride a. Extraction of soybean protein 3.2L of acid hydrolyzed liquid soybean protein solution (AJI-EKI, Ajinomoto USA, Inc.) was reduced in vacuo to give 1440g of solid powder. This solid was extracted 3 times with methanol (2L per extraction). Methanol was removed from the pooled extracts by evaporation. The yield of soybean protein as a dark brown powder was 608 g. The functional groups of the soybean protein powder was titrated using conventional procedures. See, W094l~702 21 6 0 6 9 2 PCT~S94/04561 for example, "A Laboratory Manual of Analytical Methods of Protein Chemistry," Vol. 1-3, Editors P. Alexander and R.J.
Block, Pergamon Press, 1960 and 1961. The soybean protein contained the following functional groups: 3.7 milliequivalents-/g of COOH; 0.44 milliequivalents/g free N-terminal NH2; and 3.48 milliequivalents/g total free NH2. The molecular weight of the soybean protein ranged from 100 to 2000 D.
b. Modification of soybean protein The dried soybean protein of step (a) (600 g, 2.5 equivalents of total free NH2) was dissolved in 3L of aqueous 2N
potassium hydroxide solution (2.25 mole excess) and the solution was heated at 60~C for 30 minutes. Thereafter, benzenesulfonyl chloride (460 g, 2.60 moles) was added dropwise to the mixture and the reaction temperature was monitored so that it did not exceed 65cC. The reaction continued, with stirring, for 4 hours at 63C. The reaction mixture cooled to room temperature, then acidified to pH 3.0 with 20~ aqueous HCl solution and modified soybean protein precipitated out. The modified soybean protein was then washed twice with distilled water (lL) and dissolved in 2N aqueous sodium hydroxide solution until a pH of 8.5-9 resulted. The solution was filtered to remove particulates and the filtrate was reduced and dried in vacuo to give dry modified product (257g, yield = 24~). The product had the following titratable groups: 2.3 milliequivalents/g of COOH; 0.2 milliequivalents/g N-term~n~l free NH2; and 0.3 milliequivalents-/g total free NH2.
Example 2: Modification of soybean protein with benzoyl chloride A commercial hydrolyzed water solution of soybean protein (AJI-EKI, Ajinomoto USA, Inc.) was used in this Example without further extraction. The protein in solution contained the following functional groups: 2.6 milliequivalents/ml of COOH
and 2.0 milliequivalents/ml NH2. The molecular weight of the W094/~702 PCT~S94/04561 21~692 .
soybean protein was approximately 6.5 kD.
To the soybean solution (240 mL, 0.5 equivalents f~ee NH2) was added 107 mL of 10N aqueous potassium hydroxide solution followed by 200 mL of distilled water. The solution was then placed in an ice bath (5~C) and benz~oyl chloride (70 g, 0.5 moles) was added dropwise within a t~mperature range between 10 to 250C. The reaction mixture was ~en stirred for 4.5 hours at room temperature. The pH of the reaction mixture was then reduced from 13.2 to 2.8 with concentrated HCl. After being allowed to settle for 1 hour, the precipitated modified soybean protein was collected by filtration and washed with distilled water. The soybean protein was then dissolved in 2N aqueous sodium hydroxide solution to give a solution (pH 12.6) which was then evaporated to afford 48 g of dried product (~ yield - 41~).
Example 3: Preparation of Empty Microspheres With Modified SoYbean Protein This Example illustrates a method for the preparation and cleaning of empty modified soybean protein microspheres.
PROCEDURE
1. Reagents:
a. Modified protein powder prepared as described in Example 1 b. Anhydrous citric acid (USP) c. Gum acacia NF
d. Deionized water e. Glacial acetic acid 2. Equipment a. pH meter b. Eppendorf pipette (0-100ul) and tips c. Water bath, 40C
d. liquid nitrogen e. lyophilization flasks W094/~702 21 6 0 6 9 2 PCT~S94/04561 3. Preparation of Solutions:
a. Protein solution - Dissolve l00mg modified soybean protein in lml deionized water (or multiples thereof).
Filter through a Whatman #l filter paper (if necessary) and keep at 40C in a water bath. This is solution A.
- b. l.7 N citric acid with 0.5~ acacia - Dissolve 5g of acacia and l09g of citric acid in l liter deionized water. Incubate at 40C. This is solution B.
(a) co-administration of adjuvants (such as resorci-5 nols and non-ionic surfactants polyoxyethylene oleyl ether and n-hexadecyl polyethylene ether to increase the permeability of the intestinal walls; and ~
(b) co-administration of enzyr~tic inhibitors, such as pancreatic trypsin inhibitor, diisopropylfluorophosphate (DFF) 10 and trasylol to avoid enzymatic degradation.
The use of such substances, in drug delivery systems, is limited however either because of their:
(a) inherent toxicity when employed in effective amounts; or (b) failure to protect the activeingredient or promote its absorption; or (c) adverse interaction with the drug.
Liposomes as drug delivery systems have also been described. They provide a layer of lipid around the encapsulated 20 pharmacological agent. The use of liposomes containing heparin is disclosed in U.S. Patent No. 4,239,754 and several studies have been directed to the use of liposomes containing insulin;
e.g., Patel et al. (1976) FEBS Letters Vol. 62, page 60 and Hashimoto et al. (1979) Endocrinol. Japan, Vol. 26, page 337.
25 The use of liposomes, however, is still in the development stage and there are continuing problems, including:
(a) poor stability;
(b) inadequate shelf life;
(c) limited to low MW (< 30,000) cargoes;
(d) difficulty in manufacturing;
(e) adverse interactions with cargoes.
More recently, artificial amino acid polymers or proteinoids, forming microspheres, have been described for encapsulating pharmaceuticals. For example, U.S. Patent No.
35 4,925,673 (the '673 patent), the disclosure of which is hereby WO94/7170~ 216 0 6 9 Z PCT~594104561 incorporated by reference in its entirety, describes such microsphere constructs as well as methods for their preparation and use. The microspheres of the '673 patent are useful for encapsulating a number of active agents, however there is a need in the art for microsphere carriers that can encapsulate a broader range of active agents such as lipophilic drugs.
Additionally, the method employed in the '673 patent for preparing proteinoids results in a complex mixture of high molecular weight (MW) (~ lO00 daltons) and low MW (~ lO00 daltons) peptide-like polymers which are difficult to separate.
Moreover, small amounts of the low MW microsphere-forming proteinoids are obtained. Thus, an improved method of preparing low molecular weight sphere-forming proteinoids is also desired.
Summary of the Invention The present invention relates to a modified hydrolyzed vegetable protein microsphere and to a method for preparation of such microspheres. The invention provides stable microspheres which are preparable from inexpensive hydrolyzed vegetable protein, e.g. soybean protein, and a simple and economical method for making such microsphere. Microspheres made according to the invention display improved stability and performance in deliver-ing biologically active materials to m~mm~l S.
According to the invention, modified hydrolyzed vegetable microspheres are prepared by dissolving hydrolyzed vegetable protein in an aqueous alkaline solution and adding a chemical modifier which reacts with free amine residues present in the hydrolyzed protein. The pH of the reaction mixture is then lowered until the modified vegetable protein precipitates out from the mixture. The recovered protein readily forms micro-spheres and can be used to encapsulate various cargoes such as pharmaceutical agents. The microspheres are non-toxic and can be orally or parenterally administered to m~mm~l S. Also contemplated by the present invention are dosage unit forms that include these compositions.
W094/~702 PCT~S94/04561 2l~O~92 Description of the Drawin~s Figure 1 illustrates levels of glucose detected in rat serum taken from rats orally administered microsphere encapsulat-ed insulin or raw (unencapsulated) insulin as described in Example 4. ~
Figure 2 illustrates rat seru~ calcium levels after oral administration of calcitonin and càlcitonin encapsulated in the vegetable protein microsphere of the present invention as described in Example 5.
Figure 3 illustrates an an HPLC trace of the hydrolyzed vegetable protein before modification.
Figure 4 illustrates the the change in the hydrolyzed vegetable protein after modification with benzene sulfonyl chloride in an HPLC trace.
Detailed Description of the In~ention All patents, patent applications, and literatures cited in the specification are hereby incorporated by reference in their entirety. In the case of inconsistencies, the present disclosure, including definitions, will prevail.
The modified vegetable protein microspheres of the present invention may be prepared by reacting a hydrolyzed vegetable protein with a chemical modifying agent which reacts with free amino residues present in the protein. The modified vegetable protein is then converted into microspheres which encapsulate active ingredients, e.g. drugs. A number of advantages are obt~;n~hle by the present invention which include (a) the use of readily available and inexpensive starting materials and (b) a cost-effective method for preparing and isolating microsphere-producing modified proteins. The overall modification process is simple to perform and is ~m~n~hle to industrial scale-up production.
The compositions of the subject invention are useful W094/~702 2 1 6 ~ ~ 9 ~ PCT~S94/04561 for ~ml n; stering biologically-active agents to any ~nlm~l s such as birds; m~mm~ls such as primates and particularly humans; and insects.
According to the method of the present invention, an acid or enzyme hydrolyzed vegetable protein is useful in practicing the invention. The vegetable protein generally contains titratable carboxylic acid groups (COOH) ranging between about 3 and about 8 milliequivalents/g, preferably between about 4 and about 6 milliequivalents/g, total free amino groups (NH2) ranging between about 3 and about 9 milliequivalents/g, prefera-bly ranging between about 4 and about 7 millie~uivalents/g NH2.
The molecular weight of the vegetable protein ranges between about l00 D and about 2000 D, preferably between about 200 and about 500 D.
Hydrolyzed vegetable protein is available from a variety of commercial sources. Non-limiting examples of such sources include Ajinomoto USA, Inc. (Teaneck, NJ 07666, USA);
Central Soya Co., Inc. (Fort Wayne, IN, USA); and Champlain Industries, Inc. (Clifton, NJ, USA) and additional companies listed in "Food Engineering Master", an annual publication of Chilton Co., Radnor, PA 19089, USA. A particularly pre~erred hydrolyzed vegetable protein in practicing this invention is available from Ajinomoto USA under the tradename AJI-EKI. This produc~ is an acid hydrolyzed li~uid soybean protein which is derived from defatted soybean meal.
If desired, a dried protein extract of the hydrolyzed vegetable protein solution may be used to prepare the modified vegetable protein of the invention. The dried protein extract is preparable by extracting the hydrolyzed vegetable solution with a suitable solvent, e.g., methanol, followed by evaporating the solvent extract.
The vegetable protein is then dissolved in aqueous alkaline solution of a metal hydroxide, e.g., sodium or potassium hydroxide, and heated at a temperature ranging between about 50C
W094/~702 PCT~S94/04561 2~6~ ~ 6 and about 70C, preferably between about 50C and about 60C, for a period ranging between about 10 minutes and about 40 minutes, preferably about 15 minutes. The amount of alkali employed per mmole of titratable NH2 in the vegetable protein generally ranges between about 2 and about 3 mmole, preferably between about 2.2 and about 2.5 mmole. The pH of the solution generally ranges between about 8 and about 13, preferably;~ranging between about 9 and about 10.
Thereafter, an amine modifying agent is then added to the reaction mixture while stirring. The amine modifying agents are compositions that can react with the free amino (NH2) residues present in the protein. Some non-limiting examples of amine modifying agents useful in practicing the present invention include sulfonating agents such as benzene sulfonyl chloride and acylating agents such as benzoyl chloride.
The amount of amine modifying agent in relation to the quantity of hydrolyzed vegetable protein employed is based on the equivalents of total free NH2 in the vegetable protein. Thus, between about 0.3 and about 1.2 equivalents of modifying agent are used for each molar equivalent of total NH2 groups in vegetable protein, and preferably between about 0.6 and about 1.0 equivalents of the modifying agent for each molar equivalent of total NH2 groups in the hydrolyzed vegetable protein.
In practicing the invention, the mixture of vegetable protein and modifying agent is maintained at a temperature generally ranging between about 50C and about 70C, preferably between about 60C and about 65C for a period ranging between about 2 and about 5 hours.
The reaction is quenched by adjusting the pH of the mixture with a suitable acid, e.g., concentrated hydrochloric acid, until the pH reaches between about 2 and about 3. The mixture separates on standing at room temperature to form an opaque upper layer and a dark viscous lower layer. The upper layer is discarded and modified vegetable protein is collected W094/~702 21 6 0 69 2 PCT~S94/04561 from the lower layer by filtration. The crude modified vegetable protein is then dissolved in water at a pH ranging between about 9 and about 13, preferably between about 11 and about 13.
Insoluble materials are removed by filtration and the filtrate is dried in vacuo. The yield of modified protein generally ranges between about 30 and about 60~, usually about 45~.
The modified vegetable protein of the present invention is soluble in alkaline aqueous solution (pH> 9.0); partially soluble in ethanol, n-butanol and 1:1 (v/v) toluene/ethanol solution and insoluble in neutral water. The titratable function-al groups remaining in the vegetable protein after modification are as follows: carboxylic acid groups (COOH) ranging between about 1.5 and about 3.5 milliequivalents/g, preferably about 2.3 milliequivalents/g, amino groups (NH2) ranging between about 0.3 and about 0.9 milliequivalents/g, preferably about 0.5 milliequi-valents/g. The molecular weight of the modified vegetable protein ranges between about 200 D and about 2000 D, preferably between about 200 D and about 500 D.
The modified vegetable protein of the present invention can be used immediately to microencapsulate an active pharmaco-logical agent or the protein can be concentrated or dried by conventional means and stored for future use.
The modified vegetable protein may be purified by fractionation on solid column supports such as alumina, using methanol/n-propanol mixtures as the mobile phase; reverse phase column supports using trifluoroacetic acid/acetonitrile mixtures as the mobile phase; and ion exchange chromatography using water as the mobile phase. When anion exchange chromatography is performed, a subsequent 0-500 mM sodium chloride gradient is employed. The modified vegetable protein may also be purified by extraction with a lower alcohol such as methanol, butanol, or isopropanol to remove low molecular weight cont~m~n~nts.
The following procedure may be employed to make microspheres from purified modified vegetable protein. Modified W094/~702 PCT~S94tO4561 6 9 ~
vegetable protein is dissolved in deionized water at a concentra-tion ranging between about 75 and about 200 mg/ml, preferably about 100 mg/ml at a temperature between about 25~C and about 600C, preferably about 400C. Particulate matter rPm~;n;ng in the solution may be removed by conventional means such as gravity filtration over filter paper.
Thereafter, the protein solution, maintained at a temperature of about 400C, is mixed 1.1 (V/V) with an aqueous acid solution (also at about 400C) having an acid concentration ranging between about 0.05 N and about 2 N, preferably about 1.7 N. The resulting mixture is further incubated at 400C for a period of time effective for microsphere formation as observed by light microscopy. In practicing this invention, the preferred order o~ addition is to add the protein solution to the agueous acid solutlon.
Suitable acids include any acid which does not (a) adversely effect the protein, e.g., chemical decomposition; (b) interfere with microsphere formation; (c) interfere with microsphere encapsulation of cargo; and (d) adversely interact with the cargo. Preferred acids for use in this invention include acetic acid, citric acid, hydrochloric acid, phosphoric acid, malic acid and maleic acid.
In practicing the invention, a microsphere stabilizing additive preferably incorporated into the aqueous acid solution or into the protein solution, prior to the microsphere formation process. The presence of such additives promotes the stability and dispersibility of the microspheres in solution.
The additives may be employed at a concentration ranging between about 0.1 and 5 ~ (W/V), preferably about 0.5 ~
(W/V). Suitable, but non-limiting, examples of microsphere stabilizing additives include gum acacia, gelatin, polyethylene glycol, and polylysine.
Under the above conditions, the carrier forms hollow or solid matrix type microspheres wherein the cargo is distributed in a carrier matrix or capsule type microspheres encapsulating W094l~702 21 6 0 6 9 2 PCT~S94/04561 liquid or solid cargo. If the carrier microspheres are formed in the presence of a soluble material, e.g., a pharmaceutical agent in the aforementioned aqueous acid solution, this material will be incorporated in the microspheres. In this way, one can incorporate pharmacologically active materials such as peptides, proteins, and polysaccharides as well as charged organic molecules, e.g., antimicrobial agents, which normally have poor bioavailability by the oral route. The amount of ph~rm~ceutical agent which may be incorporated in the microsphere is dependent on a number of factors which include the concentration of agent in the microsphere forming solution, as well as the affinity of the cargo for the carrier.
Under these conditions, the modified vegetable protein molecules form hollow microspheres of less than lO microns in diameter. If the protein microspheres are formed in the presence of a soluble material, e.g., a pharmaceutical agent in the aforementioned aqueous acid solution, this material will be encapsulated in the hollows of the microspheres and confined within the protein wall defined by the spherical structure. In this way, one can encapsulate pharmacologically active materials such as peptides, proteins, and polysaccharides as well as charged organic molecules, e.g., quinolones or antimicrobial agents, having poor bioavailability by the oral route. The amount of pharmaceutical agent which may be encapsulated by the microsphere is dependent on a number of factors which include the concentration of agent in the encapsulating solution, as well as the affinity of the cargo for the carrier.
Biologically-active agents suitable for use with carriers disclosed herein include, but are not limited to, peptides, and particularly small peptide hormones, which by themselves do not pass or only pass slowly through the gastro-intestinal mucosa and/or are susceptible to chemical cleavage by acids and enzymes in the gastro-intestinal tract; polysaccharides and particularly mixtures of mucopolysaccharides; carbohydrates;
lipids; or any combination thereof. Examples include, but are W094/~702 21~ ~ 6 9 ~ PCT~S94/04561 ~
not limited to, human growth hormone; bovine growth hormone;
growth hormone releasing hormone; interferons; interleukin-I;
insulin; heparin, and particularly low molecular weight heparin;
calcitonin; erythropoietin; atrial naturetic factor; antigens;
monoclonal antibodies; somatostati~i adrenocorticotropin;
gonadotropin releasing hormone; oxytocin; vasopressin; cromolyn sodium (sodium or disodium cromoglycate); vancomycin;
desferrioxamine (DFO); or any combination thereof.
Additionally the carriers of the present invention can be used to deliver other active agents such as pesticides and the like.
The amount of active agent in the composition typically is a pharmacologically or biologically effective amount.
However, the amount can be less than a ph~rm~cologically or biologically effective amount when the composition is used in a dosage unit form, such as a capsule, a tablet or a liquid, because the dosage unit form may contain a multiplicity of carrier/biologically-active agent compositions or may contain a divided pharmacologically or biologically effective amount. The total effective amounts will be administered by cumulative units containing in total pharmacologically or biologically active amounts of biologically-active agent.
Dosage unit forms can also include any of excipients;
diluents; disintegrants; lubricants; plasticizers; colorants; and dosing vehicles, including, but not limited to water, 1,2-propane diol, ethanol, olive oil, or any combination thereof.
The modified vegetable protein microspheres of the invention are pharmacologically harmless and do not alter the physiological and biological properties of the active agent.
Furthermore, the encapsulation process does not alter the pharmacological properties of the active agent. While any pharmacological agent can be encapsulated within the protein microspheres, it is particularly valuable for delivering chemical or biological agents which otherwise would be destroyed or rendered less effective by conditions encountered within the body W094/~702 2 ~ G 0 6 ~ 2 PCT~S94/04561 o~ the m~mm~l to which it is administered, before the microsphere reaches its target zone (i.e., the area in which the contents of the microsphere are to be released) and which are poorly absorbed in the gastrointestinal tract.
The protein microspheres of the invention are particu-larly useful for the oral administration of certain pharmacologi-cal agents, e.g., small peptide hormones, which, by themselves, pass slowly or not at all through the gastro-intestinal mucosa and/or are susceptible to chemical cleavage by acids and enzymes in the gastrointestinal tract. Non-limiting examples of such agents include human or bovine growth hormone, interferon and interleukin-II, calcitonin, atrial naturetic factor, antigens and monoclonal antibodies.
The particle size of the microsphere plays an important role in determ;nlng release of the active agent in the targeted area o~ the gastrointestinal tract. Microspheres having diameters between about ~ O.l microns and about lO microns, preferably between about 5.0 microns and about O.l microns, and encapsulating active agents are sufficiently small to effectively release the active agent at the targeted area within the gastrointestinal tract. Small microspheres can also be ~m;n;s-tered parenterally by being suspended in an appropriate carrier fluid (e.g., isotonic saline) and injected into the circulatory system or subcutaneously. The mode of administration selected will, of course, vary, depending upon the requirement o~ the active agent being administered. Large protein microspheres (>lO
microns) tend to be less effective as oral delivery systems.
The size of the microspheres formed by contacting modified vegetable protein with water or an aqueous solution containing active agents can be controlled by manipulating a variety of physical or chemical parameters, such as the pH, osmolarity or ionic strength of the encapsulating solution, and by the choice of acid used in the encapsulating process.
The vegetable protein-derived microspheres of the present invention are suitable for oral administration of peptide W094/~702 PCT~S94104561 21~0~92 ~
~ 12 hormones, e.g., insulin, and polysaccharides, e.y., heparin, which otherwise would be quickly destroyed in the stomach. They also are suitable ~or protecting the stomach ~rom gastric irritants, such as aspirin and NSAID~S~. When such aspirin containing microspheres are orally ~m; n~ stered, they pass through the gastrointestinal mucosa and release the aspirin far more rapidly than conventional enterically coated aspirin, which first must traverse the stomach and then must enter the blood-stream from the intestine after the enteric coating has dis-solved.
The microspheres of the invention may be orallyadministered alone as solids in the form of tablets, pellets, capsules, and granulates suitable for suspension in liquids such as water or edible oils. Similarly, the microspheres can be formulated into a composition containing one or more physiologi-cally compatible carriers or excipients, and which can be administered via the oral route. These compositions may contain conventional ingredients such as gelatin, polyvinylpyrrolidone and fillers such as starch and methyl cellulose. Alternatively, small microspheres (size less than lO ~m) can be administered via the parenteral route.
The following examples are illustrative of the invention but are not intended to limit the scope of the lnvention.
Exam~le l: Modification of Soybean protein with benzenesulfonyl chloride a. Extraction of soybean protein 3.2L of acid hydrolyzed liquid soybean protein solution (AJI-EKI, Ajinomoto USA, Inc.) was reduced in vacuo to give 1440g of solid powder. This solid was extracted 3 times with methanol (2L per extraction). Methanol was removed from the pooled extracts by evaporation. The yield of soybean protein as a dark brown powder was 608 g. The functional groups of the soybean protein powder was titrated using conventional procedures. See, W094l~702 21 6 0 6 9 2 PCT~S94/04561 for example, "A Laboratory Manual of Analytical Methods of Protein Chemistry," Vol. 1-3, Editors P. Alexander and R.J.
Block, Pergamon Press, 1960 and 1961. The soybean protein contained the following functional groups: 3.7 milliequivalents-/g of COOH; 0.44 milliequivalents/g free N-terminal NH2; and 3.48 milliequivalents/g total free NH2. The molecular weight of the soybean protein ranged from 100 to 2000 D.
b. Modification of soybean protein The dried soybean protein of step (a) (600 g, 2.5 equivalents of total free NH2) was dissolved in 3L of aqueous 2N
potassium hydroxide solution (2.25 mole excess) and the solution was heated at 60~C for 30 minutes. Thereafter, benzenesulfonyl chloride (460 g, 2.60 moles) was added dropwise to the mixture and the reaction temperature was monitored so that it did not exceed 65cC. The reaction continued, with stirring, for 4 hours at 63C. The reaction mixture cooled to room temperature, then acidified to pH 3.0 with 20~ aqueous HCl solution and modified soybean protein precipitated out. The modified soybean protein was then washed twice with distilled water (lL) and dissolved in 2N aqueous sodium hydroxide solution until a pH of 8.5-9 resulted. The solution was filtered to remove particulates and the filtrate was reduced and dried in vacuo to give dry modified product (257g, yield = 24~). The product had the following titratable groups: 2.3 milliequivalents/g of COOH; 0.2 milliequivalents/g N-term~n~l free NH2; and 0.3 milliequivalents-/g total free NH2.
Example 2: Modification of soybean protein with benzoyl chloride A commercial hydrolyzed water solution of soybean protein (AJI-EKI, Ajinomoto USA, Inc.) was used in this Example without further extraction. The protein in solution contained the following functional groups: 2.6 milliequivalents/ml of COOH
and 2.0 milliequivalents/ml NH2. The molecular weight of the W094/~702 PCT~S94/04561 21~692 .
soybean protein was approximately 6.5 kD.
To the soybean solution (240 mL, 0.5 equivalents f~ee NH2) was added 107 mL of 10N aqueous potassium hydroxide solution followed by 200 mL of distilled water. The solution was then placed in an ice bath (5~C) and benz~oyl chloride (70 g, 0.5 moles) was added dropwise within a t~mperature range between 10 to 250C. The reaction mixture was ~en stirred for 4.5 hours at room temperature. The pH of the reaction mixture was then reduced from 13.2 to 2.8 with concentrated HCl. After being allowed to settle for 1 hour, the precipitated modified soybean protein was collected by filtration and washed with distilled water. The soybean protein was then dissolved in 2N aqueous sodium hydroxide solution to give a solution (pH 12.6) which was then evaporated to afford 48 g of dried product (~ yield - 41~).
Example 3: Preparation of Empty Microspheres With Modified SoYbean Protein This Example illustrates a method for the preparation and cleaning of empty modified soybean protein microspheres.
PROCEDURE
1. Reagents:
a. Modified protein powder prepared as described in Example 1 b. Anhydrous citric acid (USP) c. Gum acacia NF
d. Deionized water e. Glacial acetic acid 2. Equipment a. pH meter b. Eppendorf pipette (0-100ul) and tips c. Water bath, 40C
d. liquid nitrogen e. lyophilization flasks W094/~702 21 6 0 6 9 2 PCT~S94/04561 3. Preparation of Solutions:
a. Protein solution - Dissolve l00mg modified soybean protein in lml deionized water (or multiples thereof).
Filter through a Whatman #l filter paper (if necessary) and keep at 40C in a water bath. This is solution A.
- b. l.7 N citric acid with 0.5~ acacia - Dissolve 5g of acacia and l09g of citric acid in l liter deionized water. Incubate at 40C. This is solution B.
4. Preparation of Microspheres:
a. Add all of solution A to solution B rapidly in one step while swirling solution B by hand, in a 40C water bath.
Exam~le 4: Preparation of Soybean protein Microsphere containinq Encapsulated Insulin This Example describes a method for the preparation and cleaning of insulin microspheres.
PROCEDURE
l. Reagents:
a. Modified protein powder prepared as described in Example l b. Heparin c. Anhydrous citric acid (USP) d. Gum acacia NF
e. Deionized water f. Desiccant g. Liquid nitrogen 2. Equipment:
a. Magnetic stirrer b. Buret c. Microscope d. Clinical centrifuge W094/~702 PCTtUS94tO4561 2~069~ 0 e. Dialysis membrane tubing (Spectrum 6, 10 mm, 50,000 M.W. Cutoff) ~. pH meter g. Lyophilizer (Labconco #75035) h. Lyophilizing flasks (150-300 mL) i. Rotating shell freezer i~' ,, . ~
j. Isopropanol/dry ice bath or!liquid N2 k. Mortar and pestle 1. Storage containers (500 mL) m. Eppendorf pipet (0-100 uL) n. Plastic closures for dialysis tubing (Spectrum) o. 2 mL syringe with 0.45 ~m Acrodisk 3. Preparation of Solutions:
a. Protein Solution A (80 mg/ml):
Add 160 mg of modified soybean protein and dissolve to 1 ml with deionized water. Using a 2 ml syringe ~ilter through a 0.45 ~m Acrodisk into a 10 ml test tube.
Keep at 40 C.
b. Solution B (1.7 N citric acid with 1~ gum):
Dissolve 10 g of acacia and 109 g of citric acid in 1 liter deionized water.
c. Solution C (Heparin solution):
Dissolve heparin in Solution B at 150 mg/mL and keep at 40 C.
4. Preparation of Microspheres:
a. Add all of solution A to solution C quickly while swirling solution C slowly, by hand, in a 40C water bath.
a. Add all of solution A to solution B rapidly in one step while swirling solution B by hand, in a 40C water bath.
Exam~le 4: Preparation of Soybean protein Microsphere containinq Encapsulated Insulin This Example describes a method for the preparation and cleaning of insulin microspheres.
PROCEDURE
l. Reagents:
a. Modified protein powder prepared as described in Example l b. Heparin c. Anhydrous citric acid (USP) d. Gum acacia NF
e. Deionized water f. Desiccant g. Liquid nitrogen 2. Equipment:
a. Magnetic stirrer b. Buret c. Microscope d. Clinical centrifuge W094/~702 PCTtUS94tO4561 2~069~ 0 e. Dialysis membrane tubing (Spectrum 6, 10 mm, 50,000 M.W. Cutoff) ~. pH meter g. Lyophilizer (Labconco #75035) h. Lyophilizing flasks (150-300 mL) i. Rotating shell freezer i~' ,, . ~
j. Isopropanol/dry ice bath or!liquid N2 k. Mortar and pestle 1. Storage containers (500 mL) m. Eppendorf pipet (0-100 uL) n. Plastic closures for dialysis tubing (Spectrum) o. 2 mL syringe with 0.45 ~m Acrodisk 3. Preparation of Solutions:
a. Protein Solution A (80 mg/ml):
Add 160 mg of modified soybean protein and dissolve to 1 ml with deionized water. Using a 2 ml syringe ~ilter through a 0.45 ~m Acrodisk into a 10 ml test tube.
Keep at 40 C.
b. Solution B (1.7 N citric acid with 1~ gum):
Dissolve 10 g of acacia and 109 g of citric acid in 1 liter deionized water.
c. Solution C (Heparin solution):
Dissolve heparin in Solution B at 150 mg/mL and keep at 40 C.
4. Preparation of Microspheres:
a. Add all of solution A to solution C quickly while swirling solution C slowly, by hand, in a 40C water bath.
5. Cleaning of Microspheres:
~ or multiples thereof.
W094/~702 21 6 0 ~ 9 2 PCT~594104561 a. Transfer the suspension with a syringe (no needle) to dialysis tubing and seal with plastic closures. Tubing should be no more than 70~ .ull.
b. Discard any amorphous material sedimented and/or aggregated on the surface.
~ c. Dialyze the microsphere suspension against acetic acid (using 20 mL of acetic acid solution per ml of micro-sphere suspension) while stirring the acetic acid solution with a magnetic stirrer.
d. Replace the acetic acid solution every hour. Continue dialyzing for a total of 3 hours.
~ or multiples thereof.
W094/~702 21 6 0 ~ 9 2 PCT~594104561 a. Transfer the suspension with a syringe (no needle) to dialysis tubing and seal with plastic closures. Tubing should be no more than 70~ .ull.
b. Discard any amorphous material sedimented and/or aggregated on the surface.
~ c. Dialyze the microsphere suspension against acetic acid (using 20 mL of acetic acid solution per ml of micro-sphere suspension) while stirring the acetic acid solution with a magnetic stirrer.
d. Replace the acetic acid solution every hour. Continue dialyzing for a total of 3 hours.
6. Lyophilization:
a. Add one part of 50~ Trehalose (Sigma) into nine parts of dialyzed microsphere solution. Flash freeze microspheres in a freeze-drying flask using the shell freezer adjusted to rotate at ca. l90 rpm and immersed in a liquid nitrogen bath.
b. Freeze dry for 24 hours or until dry as evidenced by lack of self-cooling.
c. Record weight of dry microspheres.
d. Grind to a fine powder with mortar and pestle.
e. Transfer to amber container, seal with desiccant, and store at room temperature.
a. Add one part of 50~ Trehalose (Sigma) into nine parts of dialyzed microsphere solution. Flash freeze microspheres in a freeze-drying flask using the shell freezer adjusted to rotate at ca. l90 rpm and immersed in a liquid nitrogen bath.
b. Freeze dry for 24 hours or until dry as evidenced by lack of self-cooling.
c. Record weight of dry microspheres.
d. Grind to a fine powder with mortar and pestle.
e. Transfer to amber container, seal with desiccant, and store at room temperature.
7. Resuspension:
a. Weigh the lyophilized powder and calculate the amount of protein in the powder.
b. Add 0.85 N citric acid into the lyophilized powder at 40C. The final concentration of protein is 80 mg/ml.
Example 5: Evaluation of Insulin Microspheres in Rats In this Example, the insulin microspheres prepared in accordance with Example 3 were evaluated in rats. Twelve rats w094/~702~ ~16 a 6 9 2 PCT~S9~/04561 were divided into two groups as follows:
l. oral insulin microspheres: 3 mg insulin/kg body weight by oral gavage (six rats);
2, Raw insulin (no encaps,ulation): 3 mg insulin/kg body weight by oral ga~age (six rats).
Oral gavage dosing of ~ts was performed. Insulin microspheres were prepared immedi~ately prior to dosing and Group l rats each receive an appropriate dosage of the microsphere suspension. Group 2 rats received the unencapsulated insulin.
Approximately 0.5 ml of blood was withdrawn from each rat just prior to dosing ("0" time) and l to 6 h post-dosing. Serum from the blood samples were stored at -20C.
The glucose levels of thawed serum taken from the rats were analyzed by conventional methods. As shown in Figure l, sharp decreases in serum glucose levels were observed in groups l rats receiving the encapsulated insulin. In contrast, the serum glucose levels in group 2 rats slightly increased from t ~
0. The results show that encapsulated insulin had a greater biological effect, when administered orally, in contrast to unencapsulated insulin.
Example 6: Preparation of Microsphere Encapsulated Calcitonin Encapsulation of salmon calcitonin in soybean protein microspheres were performed in the same manner described in Example 3. Calcitonin was obtained from Sandoz (Basil, Switzer-land) and a 150 mg/mL calcitonin solution in l.7 N citric acid solution with l~ gum was prepared as described in Example 3.
Example 7: Evaluation of Calcitonin Micros~heres in Rats In this Example, the calcitonin microspheres prepared in accordance with Example 5 were evaluated in rats. Twelve rats were divided into two groups as follows:
l. oral calcitonin microspheres: 60 ~g calcitonin/kg body weight by oral gavage (six rats).
W094/~702 21 6 0 69 ~ PCT~S94/04561 2. oral unencapsulated microspheres: 60 ~g calci-tonin/kg body weight by oral gavage (3 rats) (Control).
Oral gavage dosing of rats was performed. Calci~onin microspheres were prepared immediately prior to dosing and Group 1 rats received an appropriate dosage of the microsphere suspension. Group 2 rats received the unencapsulated calcitonin.
Approximately 0.5 ml of blood was withdrawn from each rat just prior to dosing ("0" time) and 1 h, 2 h and 3 h post-dosing.
Serum from the blood samples were stored at -20C.
The calcium levels of thawed serum taken from group 1 and 2 rats were analyzed by conventional methods. As shown in Figure 2, sharp decreases in serum calcium levels were observed in group 1 rats receiving the encapsulated calcitonin. In contrast, the calcium levels in group 2 rats slightly decreased from t = 0. The results show that encapsulated calcitonin had a greater biological effect, when administered orally, in contrast to unencapsulated calcitonin.
a. Weigh the lyophilized powder and calculate the amount of protein in the powder.
b. Add 0.85 N citric acid into the lyophilized powder at 40C. The final concentration of protein is 80 mg/ml.
Example 5: Evaluation of Insulin Microspheres in Rats In this Example, the insulin microspheres prepared in accordance with Example 3 were evaluated in rats. Twelve rats w094/~702~ ~16 a 6 9 2 PCT~S9~/04561 were divided into two groups as follows:
l. oral insulin microspheres: 3 mg insulin/kg body weight by oral gavage (six rats);
2, Raw insulin (no encaps,ulation): 3 mg insulin/kg body weight by oral ga~age (six rats).
Oral gavage dosing of ~ts was performed. Insulin microspheres were prepared immedi~ately prior to dosing and Group l rats each receive an appropriate dosage of the microsphere suspension. Group 2 rats received the unencapsulated insulin.
Approximately 0.5 ml of blood was withdrawn from each rat just prior to dosing ("0" time) and l to 6 h post-dosing. Serum from the blood samples were stored at -20C.
The glucose levels of thawed serum taken from the rats were analyzed by conventional methods. As shown in Figure l, sharp decreases in serum glucose levels were observed in groups l rats receiving the encapsulated insulin. In contrast, the serum glucose levels in group 2 rats slightly increased from t ~
0. The results show that encapsulated insulin had a greater biological effect, when administered orally, in contrast to unencapsulated insulin.
Example 6: Preparation of Microsphere Encapsulated Calcitonin Encapsulation of salmon calcitonin in soybean protein microspheres were performed in the same manner described in Example 3. Calcitonin was obtained from Sandoz (Basil, Switzer-land) and a 150 mg/mL calcitonin solution in l.7 N citric acid solution with l~ gum was prepared as described in Example 3.
Example 7: Evaluation of Calcitonin Micros~heres in Rats In this Example, the calcitonin microspheres prepared in accordance with Example 5 were evaluated in rats. Twelve rats were divided into two groups as follows:
l. oral calcitonin microspheres: 60 ~g calcitonin/kg body weight by oral gavage (six rats).
W094/~702 21 6 0 69 ~ PCT~S94/04561 2. oral unencapsulated microspheres: 60 ~g calci-tonin/kg body weight by oral gavage (3 rats) (Control).
Oral gavage dosing of rats was performed. Calci~onin microspheres were prepared immediately prior to dosing and Group 1 rats received an appropriate dosage of the microsphere suspension. Group 2 rats received the unencapsulated calcitonin.
Approximately 0.5 ml of blood was withdrawn from each rat just prior to dosing ("0" time) and 1 h, 2 h and 3 h post-dosing.
Serum from the blood samples were stored at -20C.
The calcium levels of thawed serum taken from group 1 and 2 rats were analyzed by conventional methods. As shown in Figure 2, sharp decreases in serum calcium levels were observed in group 1 rats receiving the encapsulated calcitonin. In contrast, the calcium levels in group 2 rats slightly decreased from t = 0. The results show that encapsulated calcitonin had a greater biological effect, when administered orally, in contrast to unencapsulated calcitonin.
Claims (37)
1. A microsphere for encapsulating a cargo, said microsphere comprising a hydrolyzed vegetable protein modified with an amine reactive modifying agent.
2. The microsphere according to claim 1, wherein said hydrolyzed vegetable protein comprises acid hydrolyzed soybean protein.
3. The microsphere according to claim 1, wherein said microsphere has a diameter equal to or less than 10 microns.
4. The microsphere according to claim 1, wherein said amine reactive modifying agent is selected from the group consisting of benzene sulfonyl chloride and benzoyl chloride.
5. The composition comprising a biologically-active agent encapsulated within a hydrolyzed vegetable protein microsphere, said microsphere comprising a biocompatible protein wall comprising a hydrolyzed vegetable protein modified with a amine reactive modifying agent.
6. The composition according to claim 5, wherein said amine reactive modifying agent is selected from the group consisting of benzene sulfonyl chloride and benzoyl chloride.
7. The composition according to claim 5, wherein said biologically-active agent comprises a monoclonal antibody, insulin, calcitonin, or erythropoietin.
8. The composition according to claim 5, wherein said hydrolyzed vegetable protein comprises acid hydrolyzed soybean protein.
9. A method for preparing a modified hydrolyzed vegetable protein microsphere comprising the steps of:
(a) mixing a hydrolyzed vegetable protein with an aqueous alkaline solution to form a solution;
(b) treating said solution with an amine reactive agent to form a mixture containing a modified hydrolyzed vegetable protein;
(c) recovering said modified hydrolyzed vegetable protein;
(d) incubating said modified hydrolyzed vegetable protein in a aqueous acid solution to form said modified hydrolyzed vegetable protein microspheres; and (e) collecting said protein microspheres.
(a) mixing a hydrolyzed vegetable protein with an aqueous alkaline solution to form a solution;
(b) treating said solution with an amine reactive agent to form a mixture containing a modified hydrolyzed vegetable protein;
(c) recovering said modified hydrolyzed vegetable protein;
(d) incubating said modified hydrolyzed vegetable protein in a aqueous acid solution to form said modified hydrolyzed vegetable protein microspheres; and (e) collecting said protein microspheres.
10. The method according to claim 9, wherein said aqueous alkaline solution comprises potassium or sodium hydrox-ide.
11. The method according to claim 9, wherein step (a) is performed at a temperature ranging between about 35°C and about 40°C.
12. The method according to claim 9, wherein said amine reactive agent is selected from the group consisting of benzene sulfonyl chloride and benzoyl chloride.
13. The method according to claim 12, wherein said aqueous acid solution further comprises a biologically-active agent.
14. The method according to claim 13, wherein said biologically-active agent comprises a monoclonal antibody, insulin, calcitonin, or erythropoietin.
15. The microsphere according to claim 1, wherein said hydrolyzed vegetable protein comprises acid hydrolyzed soybean protein.
16. The composition according to claim 5, wherein said biologically-active agent is selected from the group consisting of a peptide, a mucopolysaccharide, a carbohydrate, a lipid, a pesticide or any combination thereof.
.
.
17. The composition according to claim 5, wherein said biologically-active agent is selected from the group consisting of human growth hormone, bovine growth hormone, growth hormone-releasing hormone, an interferon, interleukin-II, insulin, heparin, calcitonin, erythropoietin, atrial naturetic factor, an antigen, a monoclonal antibody, somatostatin, adrenocorticotropin, gonadotropin releasing hormone, oxytocin, vasopressin, cromolyn sodium, vancomycin, desferrioxamine (DFO), or any combination thereof.
18. The composition according to claim 17, wherein said biologically-active agent comprises an interferon, interleukin-II, insulin, heparin, calcitonin, oxytocin, vasopressin, cromolyn sodium, vancomycin, DFO or any combination thereof.
19. The composition according to claim 18, wherein said biologically-active agent is calcitonin.
20. A dosage unit form comprising (A) a composition according to claim 5; and (B) (a) an excipient, (b) a diluent, (c) a disintegrant, (d) a lubricant, (e) a plasticizer, (f) a colorant, (g) a dosing vehicle, or (h) any combination thereof.
21. A dosage unit form according to claim 20 comprising a tablet, a capsule, or a liquid.
22. A method for administering a biologically-active agent to an animal in need of said agent, said method comprising administering orally to said animal a composition as defined in claim 5.
23. The composition according to claim 5, wherein said peptide is insulin.
24. The composition according to claim 5, wherein said peptide is human growth factor.
25. The composition according to claim 5, wherein said peptide is bovine growth factor.
26. The composition according to claim 5, wherein said peptide is interferon.
27. The composition according to claim 5, wherein said peptide is interleukin II.
28. The composition according to claim 5, wherein said peptide is atrial naturetic factor.
29. The composiiton according to claim 5, wherein said peptide is calcitonin.
30. The composition according to claim 5, wherein said biologically active agent is an antimicrobial agent.
31. The composition according to claim 5, wherein said biologically active agent is a quinolone.
32. The composition according to claim 5, wherein the biologically active agent is a polysaccharide.
33. The composition according to claim 32, wherein said polysaccharide is heparin.
34. The composition according to claim 5, wherein said biologically active agent is an antigen.
35. The composition according to claim 5, wherein said biologically active agent is a monoclonal antibody.
36. A composition according to claim 5, wherein said biologically active agent is aspirin.
37. The method according to claim 5, wherein said microspheres are hollow and said biologically-active agent is encapsulated therein.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/051,739 US5401516A (en) | 1992-12-21 | 1993-04-22 | Modified hydrolyzed vegetable protein microspheres and methods for preparation and use thereof |
| US051,739 | 1993-04-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2160692A1 true CA2160692A1 (en) | 1994-10-27 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002160692A Abandoned CA2160692A1 (en) | 1993-04-22 | 1994-04-22 | Modified hydrolyzed vegetable protein microspheres and methods for preparation and use thereof |
Country Status (7)
| Country | Link |
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| EP (1) | EP0696192A4 (en) |
| JP (1) | JPH08509231A (en) |
| AU (1) | AU6668594A (en) |
| CA (1) | CA2160692A1 (en) |
| WO (1) | WO1994023702A1 (en) |
| ZA (1) | ZA939608B (en) |
| ZW (1) | ZW17893A1 (en) |
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| US5667806A (en) * | 1995-06-07 | 1997-09-16 | Emisphere Technologies, Inc. | Spray drying method and apparatus |
| CA2377204C (en) * | 1999-06-29 | 2015-01-20 | Pharmaceutical Discovery Corporation | Purification and stabilization of peptide and protein pharmaceutical agents |
| US9006175B2 (en) | 1999-06-29 | 2015-04-14 | Mannkind Corporation | Potentiation of glucose elimination |
| SI1494732T1 (en) | 2002-03-20 | 2008-08-31 | Mannking Corp | Inhalation apparatus |
| EP1786784B1 (en) | 2004-08-20 | 2010-10-27 | MannKind Corporation | Catalysis of diketopiperazine synthesis |
| KR101306384B1 (en) | 2004-08-23 | 2013-09-09 | 맨카인드 코포레이션 | Diketopiperazine salts, diketomorpholine salts or diketodioxane salts for drug delivery |
| JP2008524266A (en) | 2004-12-22 | 2008-07-10 | コラローム インコーポレイティド | Natural water-insoluble encapsulated composition and process for its production |
| AU2006290227B2 (en) | 2005-09-14 | 2012-08-02 | Mannkind Corporation | Method of drug formulation based on increasing the affinity of crystalline microparticle surfaces for active agents |
| RU2403059C2 (en) | 2006-02-22 | 2010-11-10 | Маннкайнд Корпорейшн | Method of improving pharmaceutical properties of particles, containing diketopiperazine and active agent |
| KR101629154B1 (en) | 2008-06-13 | 2016-06-21 | 맨카인드 코포레이션 | A dry powder inhaler and system for drug delivery |
| US8485180B2 (en) | 2008-06-13 | 2013-07-16 | Mannkind Corporation | Dry powder drug delivery system |
| DK2300083T3 (en) | 2008-06-20 | 2013-07-22 | Mannkind Corp | INTERACTIVE DEVICE AND PROCEDURE FOR REAL-TIME PROFILING INHALATION TESTS |
| TWI614024B (en) | 2008-08-11 | 2018-02-11 | 曼凱公司 | Use of ultrarapid acting insulin |
| US8314106B2 (en) | 2008-12-29 | 2012-11-20 | Mannkind Corporation | Substituted diketopiperazine analogs for use as drug delivery agents |
| MX2011009512A (en) | 2009-03-11 | 2011-11-29 | Mannkind Corp | Apparatus, system and method for measuring resistance of an inhaler. |
| SG176738A1 (en) | 2009-06-12 | 2012-01-30 | Mannkind Corp | Diketopiperazine microparticles with defined specific surface areas |
| CA2778698A1 (en) | 2009-11-03 | 2011-05-12 | Mannkind Corporation | An apparatus and method for simulating inhalation efforts |
| BR112012033060A2 (en) | 2010-06-21 | 2018-02-27 | Mannkind Corp | Dry powder drug release system methods |
| CN105667994B (en) | 2011-04-01 | 2018-04-06 | 曼金德公司 | Blister package for pharmaceutical kit |
| WO2012174472A1 (en) | 2011-06-17 | 2012-12-20 | Mannkind Corporation | High capacity diketopiperazine microparticles |
| US9233159B2 (en) | 2011-10-24 | 2016-01-12 | Mannkind Corporation | Methods and compositions for treating pain |
| SG10201605800UA (en) | 2012-07-12 | 2016-09-29 | Mannkind Corp | Dry powder drug delivery system and methods |
| EP2911690A1 (en) | 2012-10-26 | 2015-09-02 | MannKind Corporation | Inhalable influenza vaccine compositions and methods |
| JP6523247B2 (en) | 2013-03-15 | 2019-05-29 | マンカインド コーポレイション | Method of making microcrystalline diketopiperazine particles and method of making dry powder composition |
| CN114848614A (en) | 2013-07-18 | 2022-08-05 | 曼金德公司 | Heat stable dry powder pharmaceutical compositions and methods |
| CA2920488C (en) | 2013-08-05 | 2022-04-26 | Mannkind Corporation | Insufflation apparatus and methods |
| WO2015148905A1 (en) | 2014-03-28 | 2015-10-01 | Mannkind Corporation | Use of ultrarapid acting insulin |
| US10561806B2 (en) | 2014-10-02 | 2020-02-18 | Mannkind Corporation | Mouthpiece cover for an inhaler |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3565559A (en) * | 1968-03-11 | 1971-02-23 | Sumitomo Chemical Co | Process for making microcapsules |
| JP2670680B2 (en) * | 1988-02-24 | 1997-10-29 | 株式会社ビーエムジー | Polylactic acid microspheres containing physiologically active substance and method for producing the same |
| US5401516A (en) * | 1992-12-21 | 1995-03-28 | Emisphere Technologies, Inc. | Modified hydrolyzed vegetable protein microspheres and methods for preparation and use thereof |
-
1993
- 1993-12-22 ZA ZA939608A patent/ZA939608B/en unknown
- 1993-12-30 ZW ZW17893A patent/ZW17893A1/en unknown
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- 1994-04-22 EP EP94915419A patent/EP0696192A4/en not_active Withdrawn
- 1994-04-22 WO PCT/US1994/004561 patent/WO1994023702A1/en not_active Application Discontinuation
- 1994-04-22 JP JP6523596A patent/JPH08509231A/en active Pending
- 1994-04-22 CA CA002160692A patent/CA2160692A1/en not_active Abandoned
- 1994-04-22 AU AU66685/94A patent/AU6668594A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| ZA939608B (en) | 1994-08-24 |
| WO1994023702A1 (en) | 1994-10-27 |
| EP0696192A4 (en) | 1996-09-11 |
| EP0696192A1 (en) | 1996-02-14 |
| AU6668594A (en) | 1994-11-08 |
| JPH08509231A (en) | 1996-10-01 |
| ZW17893A1 (en) | 1994-07-27 |
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