JP2006257074A - Medicinal composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medicinal composition making a physiologically active protein in a state holding an activity migrate into blood by orally or enterally administering the physiologically active protein and to thereby provide a medicine affording oral and enteral administration of the physiologically active protein and remarkably ameliorating pains and inconvenience of patients. <P>SOLUTION: The medicinal composition makes the physiologically active protein in the state holding the sufficient activity migrate from the interior of an alimentary canal into blood. The composition comprises the physiologically active protein and a cationic peptide as ingredients. Furthermore, the physiologically active protein is not linked to the cationic peptide with a covalent bond. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pharmaceutical composition for transferring from the intestinal tract into the blood while maintaining the activity of a physiologically active protein.

  So far, several physiologically active substances consisting of peptides and proteins have appeared in the clinical field and have been used as pharmaceuticals and have shown remarkable therapeutic effects. However, the administration method is currently limited to injections in most cases. This is because when peptides and proteins are orally administered, they are degraded by proteases present in the digestive tract, and since only a small portion of peptides and proteins orally administered is in the blood due to low absorption efficiency from the intestinal tract. The main reason is not to reach. Especially for the latter, since the intestinal tract plays a role as a barrier to prevent substances that are inherently harmful to the living body from entering the body, the intestinal epithelial cell layer essentially has a molecular weight above a certain level such as peptides and proteins. It has a property that it is difficult to permeate the hydrophilic substance it has, and it is considered very difficult to transfer the bioactive protein into the blood across this barrier.

  Administering drugs by injection is a heavy burden for patients and doctors, especially when treatment is frequent and long-term, and various methods for enabling the administration of bioactive peptides and proteins have been studied. It was. For example, attempts have been made to artificially improve the permeability of the intestinal tract by coexisting a surfactant as an additive. However, using a substance that non-specifically increases the intestinal permeability is a substance harmful to the living body. The risk of entering the body cannot be excluded.

  In recent years, it has been found that a cationic peptide having a specific sequence has a property of permeating a cell membrane despite being hydrophilic. Among them, partial peptides of HIV-1 Tat protein and oligomer peptides consisting of 6-9 arginine residues have been shown to efficiently permeate the cell membrane and migrate into the cells. It has been reported that a target substance can be efficiently taken into a cell by conjugating a protein, DNA, sugar or the like to the peptide (see Patent Documents 1 and 2).

  Although such a cell-permeable peptide-drug conjugate can be used to permeate the intestinal wall into the blood through the intestinal wall, it has been presented as a possibility, but has been demonstrated. Not. This means that translocation of the drug into the blood through the intestinal wall permeates the two barriers, the brush border membrane on the lumen side and the basolateral membrane on the blood vessel side of the epithelial cells that make up the intestinal wall cell layer. This is thought to be due to the need for functions different from the entry into cells. Moreover, a problem in the case of using a conjugate in which a cell-permeable peptide and a drug are covalently bonded is that the structure of the drug is changed by conjugation. In particular, when the drug is a bioactive peptide or protein, it is difficult to selectively bind a permeable peptide selectively to a specific site of the peptide / protein. Thus, it is expected that a site important for the expression of physiological activity is modified and the activity is reduced. In particular, in the case of a bioactive peptide / protein having a small molecular weight, it is considered that it is more susceptible to modification.

In addition, as a trial to improve intestinal absorbability without performing covalent bond modification to a physiologically active protein, a method of coexisting a low molecular weight amino acid derivative having a hydrophobic moiety in the molecule as a permeable carrier has been reported (patent) In this method, it is thought that uptake occurs due to the nonspecific and passive weak action of the hydrophobic part in the coexisting amino acid derivative and the cell membrane, and the bioactive protein is transferred to the blood with high efficiency. It is difficult to achieve this, and the amount of carriers used is inevitably increased. This leads to concern about undesirable effects caused by administering a large amount of a carrier, which is a modified amino acid derivative that is not a biological component, to the living body. Moreover, it is not desirable from the viewpoint of cost to require a large amount of carriers.
JP 2001-199997 A Special table 2003-523984 gazette JP-T 8-509474

  An object of the present invention is to provide a pharmaceutical composition that can be transferred into the blood while maintaining its activity by oral or enteral administration of a physiologically active protein.

  In order to overcome the above-mentioned problems, the present inventors have studied a means for improving permeability of a physiologically active protein having low blood translocation by oral administration under normal conditions. It has been found that compositions in which the cationic peptide is not covalently bound are effective.

  That is, the present invention has the following configuration.

  A pharmaceutical composition for transferring a physiologically active protein from the intestinal tract into the blood with sufficient activity, containing the physiologically active protein and the cationic peptide as components, and sharing the physiologically active protein and the cationic peptide A pharmaceutical composition not linked by a bond.

  According to the present invention, a physiologically active protein can be orally or enterally administered, and a simple and patient-friendly drug treatment can be achieved as compared with conventional administration methods by injection.

  The present invention relates to a pharmaceutical composition for transferring a physiologically active protein from the intestinal tract into the blood while maintaining a sufficient activity, comprising a physiologically active protein and a cationic peptide as components, and the physiologically active protein and the cation It is a pharmaceutical composition in which the sex peptide is not covalently linked.

  The cationic peptide used in the present invention refers to a peptide containing at least one basic amino acid (arginine or lysine or histidine) and having a positive charge under neutral conditions. The length of the peptide is preferably 50 amino acid residues or less, more preferably 20 amino acid residues or less, and still more preferably 10 amino acid residues or less. The proportion of basic amino acids in the total amino acids constituting the peptide is preferably 30% or more, more preferably 50% or more, and even more preferably 70% or more is composed of basic amino acids.

  The cationic peptide used in the present invention is preferably an arginine oligomer or a derivative thereof. Peptides containing arginine are particularly preferred, and peptides having 50% or more of all amino acid residues being arginine are more preferred. More preferred are peptides in which 70% or more is arginine. A peptide having a sequence in which 5 or more arginines are continuous is particularly preferably used.

  As the amino acid constituting the cationic peptide of the present invention, non-natural amino acids such as derivatives obtained by partially modifying the structure of natural amino acids can be used in addition to naturally occurring amino acids. For example, D-form amino acids can be effectively used because they are less susceptible to degradation by proteolytic enzymes present in the intestinal tract.

  Furthermore, the cationic peptide of the present invention is preferably a D-arginine oligomer or a derivative thereof. Furthermore, the cationic peptide of the present invention is preferably an oligomer composed of 5-15 residue D-arginine. Further, in the cationic peptide of the present invention, the cationic peptide compound is preferably protamine, a partial peptide thereof or a derivative thereof.

  The cationic peptide of the present invention can be synthesized using an ordinary peptide synthesis method. Alternatively, it can be prepared by introducing and expressing a gene encoding a sequence containing a desired cationic peptide in microorganisms such as Escherichia coli, animal cells, and insect cells. Alternatively, a naturally occurring peptide can be isolated or used after being isolated. For example, protamine isolated from the testis of fish such as salmon and herring is a proven cationic peptide that has been used safely as an injection and can be isolated and purified at low cost. Suitable as the cationic peptide of the invention. The cationic peptide can be used as a single peptide or as a mixture of two or more peptides.

  Examples of the physiologically active protein used in the present invention include peptide hormones, enzyme proteins, and antibodies. For example, parathyroid hormone (PTH), calcitonin, insulin, angiotensin, glucagon, glucagon-like peptide (GLP-1), gastrin, growth hormone, prolactin (luteal stimulating hormone), gonadotropin (gonadotropic hormone), thyotropic hormone, adrenal gland Cortical stimulating hormone, melanocyte stimulating hormone, vasopressin, oxytocin, prothyrelin, luteinizing hormone (LH), corticotropin, somatropin, thyrotropin (thyroid stimulating hormone), somatostatin (growth hormone stimulating factor), hypothalamic hormone (GnRH), G- CSF, erythropoietin, HGF, EGF, VEGF, interferon α, interferon β, interferon γ, interleukins, superoxide dismuter (SOD), it can be mentioned urokinase, lysozyme, the vaccine and the like. The physiologically active protein is preferably insulin, calcitonin, parathyroid hormone, growth hormone, interferons, interleukins, and G-CSF, and more preferably insulin.

  These physiologically active proteins may be natural proteins or peptides, or derivatives obtained by modifying a part of the sequence. Moreover, you may be the derivative | guide_body which performed chemical modification, such as polyethyleneglycol (PEG) conversion.

  The size of the physiologically active protein is not particularly limited, but in order to obtain sufficiently high intestinal permeation efficiency, the molecular weight is preferably 30000 or less, and more preferably 10,000 or less.

  The isoelectric point of the physiologically active protein used in the present invention is not particularly limited, but is preferably an isoelectric point for forming a good complex with a cationic peptide and permeating the intestinal tract with high efficiency. Is preferably 7 or less, more preferably a bioactive protein having an isoelectric point of 5.5 or less. For example, insulin is a protein with a relatively small molecular weight that requires frequent administration, and can be particularly preferably used because it has an isoelectric point of 7 or less and can form a good complex with a cationic peptide.

  When the physiologically active protein referred to in the present invention is transferred from the intestinal tract to the blood while maintaining the activity, the physiologically active protein transferred into the blood usually measures the activity under the conditions for measuring its activity, for example, an enzyme activity. In the case of a substance that acts on a cell receptor, it means that it retains the ability to bind to the receptor or to change the function of the target cell. When the activity of a physiologically active protein that has migrated into the blood is viewed as a specific activity expressed as a ratio to its abundance that can be measured by immunological measurement, etc. The specific activity) / (specific activity of physiologically active protein before intestinal permeation) is preferably 0.1 or more, and more preferably 0.5 or more.

  If the amount of the cationic peptide used in the present invention is too large, there is a possibility that it exhibits a non-specific damaging action on the intestinal tract, and it is desirable that the dosage be small in terms of cost. Therefore, the mixing ratio of the physiologically active protein and the cationic peptide in the present pharmaceutical composition is desirably 3000 or less as a numerical value of (number of molecules of cationic peptide) / (number of molecules of physiologically active protein). Preferably it is 1000 or less, More preferably, it is 200 or less.

  The pharmaceutical composition of the present invention may contain both pharmaceutically acceptable carriers and additives. Examples of such carriers and additives include water, pharmaceutically acceptable organic solvents, collagen, polyvinyl alcohol, polyvinyl pyrrolidone, carboxyvinyl polymer, sodium carboxymethylcellulose, sodium polyacrylate, sodium alginate, water soluble dextran, Sodium carboxymethyl starch, pectin, methylcellulose, ethylcellulose, xanthan gum, gum arabic, casein, gelatin, agar, diglycerin, propylene glycol, polyethylene glycol, petroleum jelly, paraffin, stearyl alcohol, stearic acid, human serum albumin (HSA), mannitol, Examples include sorbitol, lactose, and surfactants acceptable as pharmaceutical additives.

  The pharmaceutical composition of the present invention can be used in various forms such as a solution, a solid, and a powder, but from the viewpoint of stability and ease of handling, for example, a form formed into a solid or powder by a method such as freeze-drying. Is preferable, and a powder or solid preparation is preferable.

  The pharmaceutical composition used for oral administration is preferably enteric-coated preparations such as enteric capsules or the like, or enteric-coated oral by a method such as enteric coating after tableting as tablets. Used as a pharmaceutical composition for administration.

  There are no particular restrictions on the specific form of the method for orally or enterally administering the pharmaceutical composition of the present invention to animals (including humans). For example, as an oral preparation, take a dry or solution form as it is, or take it in a capsule with excipients and take it back to water. It can be taken after being dispersed. It can also be administered directly to the rectum using the form of a suppository. The method for administering a physiologically active protein to an animal is preferably administered orally or enterally.

  INDUSTRIAL APPLICABILITY According to the present invention, oral enteral administration of physiologically active proteins that have been used as injections so far is possible, and a drug that greatly improves patient pain and inconvenience can be provided. Improving the pain and inconvenience of hospital visits caused by these injections not only realizes patient-oriented medical care in the medical field, but also fundamentally changes the concept of protein preparations and creates innovative drugs. Leads to.

  Examples are shown below, but the present invention is not limited to these examples.

Example 1
In vivo (rat) intestinal absorption promotion effect of insulin by oligoarginine peptide.

<Method>
1. Preparation of insulin solution 1.923 mg (= 50 IU = 0.33 μmol) of human recombinant insulin (Wako Pure Chemical Industries) was weighed and dissolved in 50 μl of 0.1M hydrochloric acid. Methyl cellulose (MC) -added phosphate physiological buffer pH 7.4 (PBS) 1.2 ml and 0.1 M NaOH solution 50 μl were neutralized, and MC-added PBS 1.2 ml was added to make the total volume 2.5 ml. did. (Insulin concentration 0.769 mg / ml = 20 IU / ml).

2. Preparation of insulin-arginine 6mer peptide mixed solution L-arginine 6mer peptide or D-arginine 6mer peptide (synthesized by Sigma Genosys) 2.5 mg (2.6 μmol) or 5 mg (5.2 μmol), respectively, was weighed above 0.5 ml of the insulin solution prepared in 1 (insulin 0.385 mg = 0.066 μmol) was added and dissolved to obtain an oligoarginine peptide-insulin mixed solution. For the control (no oligoarginine peptide), the insulin solution itself was used for administration.

3. Rat intestinal absorption experiment An SD male rat weighing about 200 g fasted for 24 hours was anesthetized by intraperitoneal injection of sodium pentobarbital 50 mg / kg, and then the abdominal cavity was opened along the midline to expose the intestine. A silicon tube was inserted from the 2-3 cm ileum from the ileocecal junction, and a sonde was inserted from the upper portion of about 10 cm, and a suture was passed through the inner 6 cm portion.

  After flowing 40 ml of phosphate physiological buffer pH 7.4 (PBS) preheated to 37 ° C. from the sonde at a flow rate of 5 ml / min, the contents were discharged, and then the silicone tube was plugged, and 37 1 ml of PBS warmed to 0 ° C. was administered and stored for 30 minutes. Immediately after administration, the sonde was capped, the intestinal tract was returned to the abdominal cavity, the incision was closed with a clip, and the patient was rested.

  After storage, remove the plug of the sonde and the silicon tube, pour 20 ml of PBS preheated to 37 ° C into the loop at a flow rate of 5 ml / min to discharge the contents, and then ligate the 6 cm portion through which the suture thread was passed in advance. And created a loop. In this loop, 2. 0.5 ml of the oligoarginine peptide-insulin mixed solution prepared in (1) was administered, the intestine was returned to the abdominal cavity, the incision was closed with a clip, and the patient was rested.

  Rats in the experiment were fixed in a dorsal position on a hot plate heated to 37 ° C. with a hot water circulation pump to adjust body temperature.

  Before administration and 5, 10, 15, 30, 60, 120, 180, 240 minutes after administration, 0.25 ml of blood was collected from the jugular vein, and blood glucose level was measured using Novo Assist Plus. The remaining blood was separated into plasma by centrifugation, and the insulin concentration was quantified by enzyme immunoassay.

<Result>
For both L-arginine 6mer and D-arginine 6mer peptides, a clear increase in blood insulin concentration and a clear decrease in blood glucose level were observed compared to administration of control insulin alone (FIGS. 1 and 2). .

Example 2
Insulin in vivo (rat) intestinal absorption promotion effect by salmon protamine.

<Method>
21.5 mg (5 μmol) of salmon protamine (manufactured by Sigma) was weighed. Insulin solution 0.5 ml prepared in the same manner as in Example 1 was added and dissolved to obtain an insulin-salmon protamine mixed solution. Rat intestinal absorption was evaluated in the same manner as in Example 1.

<Result>
By administration of the salmon protamine-insulin mixed solution, a clear increase in blood insulin concentration and a clear decrease in blood glucose level were observed as compared to administration of control insulin alone (FIGS. 3 and 4).

Example 3
In vitro insulin ileal mucosa permeation promoting effect by oligoarginine peptide.

<Method>
1. Preparation of Insulin Solution Weigh 26.1 mg of human recombinant insulin (Wako Pure Chemical Industries, Ltd.), dissolve in 300 μl of 0.1M HCl solution, add 3.9 ml of Krebs-Ringer Buffer and 300 ml of 0.1M NaOH solution, and add 4. 5 ml was used as an insulin solution (1 mM).

2. Preparation of insulin-arginine 6mer peptide mixed solution 2.1 mg of L-arginine 6mer peptide was weighed and dissolved in 550 μl of the insulin solution prepared above to prepare an insulin-oligoarginine peptide mixed solution (arginine peptide concentration 4 mM, insulin concentration). 1 mM.).

3. Mucosal permeation experiment for 24 hours Wistar male rats fasted for 24 hours were anesthetized by intraperitoneal injection of pentobarbital sodium 50mg / kg. Then, 5 ml of Krebs-Ringer Buffer was added to the donor and receiver sides. After the membrane was stabilized for 20 minutes, 2 ml was collected from the donor side, and at the same time, 2 ml of a mixed solution of insulin and oligoarginine peptide was added. (Concentration during reaction: 0.4 mM insulin, 1.6 mM oligoarginine peptide.) From the start (0 minutes), 100 μl from the receiver side after 10, 15, 30, 60, 90, 120, 150, 180 minutes Was sampled (replaced with the same volume of Krebs-Ringer Buffer), and the insulin concentration was measured by enzyme immunoassay.

<Result>
When the insulin-oligoarginine peptide mixed solution was used, obvious enhancement of the ileal mucosa permeability of insulin was recognized as compared to the case of using the control insulin-only solution (FIG. 5).

Example 4
In vivo (mouse) insulin intestinal absorption promotion effect by salmon protamine.

<Method>
4 mg of human recombinant insulin (Wako Pure Chemical Industries) was weighed and dissolved in 200 μl of 0.1M hydrochloric acid. This was neutralized by adding 1.2 ml of phosphate physiological buffer pH 7.4 (PBS) and 200 μl of 0.1 M NaOH solution, and further PBS was added to make the total volume 10.5 ml. (Insulin concentration 0.38 mg / ml).

  Insulin salmon protamine mixed solution was prepared by adding 0.2 ml (76 μg) of the insulin solution prepared above to 17.5 mg of salmon protamine (manufactured by Sigma).

  BALB / c male mice fasted for 24 hours were anesthetized by injecting 15 mg / kg of pentobarbital sodium solution intraperitoneally, and then opened along the midline to expose the intestinal tract. A silicon tube was inserted from the portion close to the ileum by 2-3 cm from the ileocecal joint, and a sonde was inserted from the upper 10 cm portion, and sutures were passed through the silicon tube and the inner 2 cm portion of the sonde, respectively.

  After passing 20 ml of PBS solution preheated to 37 ° C. from the silicon tube into the intestine and washing the inside of the intestine, 0.2 ml of the insulin-sake protamine mixture prepared from the silicon tube by ligating the suture on the sonde side After administration, the suture on the silicon tube side was ligated to form a loop, and then the intestinal tract was returned to the abdominal cavity and the incision was closed with a clip to be rested. The mouse in the experiment was fixed in the dorsal position with a 37 ° C. heating mat and the body temperature was adjusted.

  Before administration, and 30, 60, 90, 120, and 150 minutes after administration, 20 μl of blood was collected from the tail artery, and blood glucose concentration was measured using Fuji Dry Chem (Fuji Film). In addition, plasma insulin obtained by centrifuging a part of blood for 10 minutes at 5000 rpm was used to quantify the insulin concentration in the blood using an insulin ELISA kit (Yanauchi Laboratories).

<Result>
When a mixed solution of protamine and insulin was administered to the intestine of a mouse, the insulin concentration in the mouse blood was clearly increased and the blood glucose level was clearly decreased as compared with the administration of control insulin alone (FIG. 6). 7).

Example 5
Effect of intestinal epithelial cell (Caco2) monolayer penetration of insulin by oligoarginine peptide.

<Method>
1. Preparation of fluorescent dye (fluorescein) labeled insulin 10 mg of human recombinant insulin (Wako Pure Chemical Industries) was weighed and dissolved in 250 μl of 0.1M HCl solution, and then 2.5 ml of PBS and 250 μl of 0.1M NaOH solution were added to make 3 ml. . This solution was desalted using a desalting column (Amersham PD-10) to obtain 6 ml of 50 mM sodium bicarbonate solution. (Insulin concentration 1.67 mg / ml). To this solution, a total amount of 4.8 mg NHS-fluorescein (Pierce) dissolved in 0.6 ml of 50 mM sodium bicarbonate solution was added and reacted at 25 ° C. for 4 hours. Further, 0.6 ml of 1 M Tris-HCl buffer (pH 8) was added and reacted for 30 minutes, and then desalted against 10 ml of pure water using a desalting column to remove unreacted NHS-fluorescein. Thus, a fluorescein-labeled insulin aqueous solution was obtained.

2. Caco2 cell monolayer permeation test In a D-MEM medium supplemented with 10% fetal calf serum, Caco-2 cells were transformed into Transwell (Corning, Inc.) under conditions of 37 ° C. and 5% CO ₂ . The membrane was cultured on a filter having a membrane diameter of 12 mm, a culture area of 1.0 cm ² and a pore size of 0.4 μm. A well-differentiated cell monolayer was obtained by changing the medium every 2 to 3 days and culturing for 21 days.
After washing the cell monolayer on the filter with an HBSS solution, an HBSS solution containing 0.77 mg / ml of fluorescein-labeled insulin and an oligoarginine peptide (L-arginine 6mer) at a concentration of 0, 1.25 or 5 mg / ml was reduced to 0. 5 ml was added to the apical side, and after 30, 60 and 120 minutes, 0.1 ml was recovered from the basolatal permeate (volume 1.5 ml), diluted 5.5 times, and then permeated with a fluorescent plate reader. Fluorescence derived from insulin (excitation wavelength: 490 nm, detection wavelength: 520 nm) was measured. The concentration of fluorescein insulin in the permeate sample was calculated based on the fluorescence measurement of a known concentration of fluorescein insulin solution.

Permeability of insulin is expressed by the following formula: total amount of insulin permeated to the basolatal side (μg) / total amount of insulin added to the apical side (μg) × 100 (%)
Calculated with

<Result>
By the addition of oligoarginine peptide (L-Arg6mer), a clear increase in the amount of permeated insulin was observed (Table 1).

Example 6
Interferon in vivo (rat) intestinal absorption promotion effect by oligoarginine peptide.

<Method>
A 0.5 ml PBS solution containing 5 mg of L-arginine 6mer peptide and interferon β (manufactured by Toray) was prepared, and the whole amount was administered into the rat intestine in the same manner as in Example 1. The amount of interferon β to be administered was adjusted to be 2.25 × 10 ⁶ IU per kg body weight of the rat. Blood was collected over time, and the interferon β concentration in the plasma was measured by ELISA (Kamakura Techno Science Co., Ltd. kit).

<Result>
By administering the oligoarginine-interferon β mixed solution, an increase in blood interferon β concentration was observed as compared to the control interferon β alone (FIG. 8).

The result of having measured the insulin concentration in the plasma sample which administered each amount of the L-arginine or D-arginine 6mer peptide mixed with the insulin in a rat intestinal loop, and collected blood over time is shown. Insulin solution shows the result in control rats administered with insulin alone. The blood glucose level measurement result in each sample of FIG. 1 is shown. Insulin mixed with salmon protamine is administered into a rat intestinal loop, and the insulin concentration in a plasma sample collected over time is shown. Insulin solution shows the result in control rats administered with insulin alone. The blood glucose level measurement result in each sample of FIG. 3 is shown. In the in vitro ileal mucosa permeation experiment of Example 3, the insulin concentration in the permeate was measured over time in the presence and absence (control) of L-arginine 6mer peptide and displayed as the cumulative permeation amount. Results are shown. Insulin mixed with salmon protamine is administered into the mouse intestinal loop, and the insulin concentration in the plasma sample collected over time is shown. Insulin solution shows the result in a control mouse administered with only insulin. The blood glucose level measurement result in each sample of FIG. 6 is shown. The result of having measured interferon beta concentration in the plasma sample which administered interferon beta mixed with L-arginine 6mer peptide in a rat intestinal loop and collected blood over time is shown. Interferon solution shows the result in control rats administered with only interferon β. Each value represents the average value of n = 3 experiments.

Claims (12)

  A pharmaceutical composition for transferring a physiologically active protein from the intestinal tract into the blood with sufficient activity, containing the physiologically active protein and the cationic peptide as components, and sharing the physiologically active protein and the cationic peptide A pharmaceutical composition not linked by a bond.   The pharmaceutical composition according to claim 1, wherein the mixing ratio of the cationic peptide and the physiologically active protein is 3000 or less as a molar ratio ((number of moles of cationic peptide) / (number of moles of physiologically active protein)).   The pharmaceutical composition according to claim 1 or 2, wherein the cationic peptide is an arginine oligomer or a derivative thereof.   The pharmaceutical composition according to claim 1 or 2, wherein the cationic peptide is a D-arginine oligomer or a derivative thereof.   The pharmaceutical composition according to claim 1 or 2, wherein the cationic peptide is an oligomer composed of 5-15 residue D-arginine.   The pharmaceutical composition according to claim 1 or 2, wherein the cationic peptide compound is protamine or a partial peptide thereof or a derivative thereof.   The pharmaceutical composition according to any one of claims 1 to 6, wherein the physiologically active protein has an isoelectric point of 7 or less.   The pharmaceutical composition according to any one of claims 1 to 7, wherein the molecular weight of the physiologically active protein is 30000 or less.   The pharmaceutical composition according to any one of claims 1 to 8, wherein the physiologically active protein is selected from insulin, calcitonin, parathyroid hormone, growth hormone, interferons, interleukins, and G-CSF.   The pharmaceutical composition according to any one of claims 1 to 8, wherein the physiologically active protein is insulin.   The pharmaceutical composition according to any one of claims 1 to 10, which is a powder or a solid preparation.   A method for administering a physiologically active protein to an animal, wherein the pharmaceutical composition according to any one of claims 1 to 11 is orally or enterally administered.

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