TECHNICAL FIELD

The present application is filed claiming the priority of the Japanese Patent Application No. 2016-93407, the entire contents of which are herein incorporated by reference.

The present invention relates to a pharmaceutical composition containing a macromolecular drug, particularly an injection, and a method for producing the same.

BACKGROUND ART

Many conventional carcinostatic agents (also referred to as antitumor agents or anticancer agents) have a molecular weight of 1500 or less. Most of such agents diffuse uniformly in the body, and thus cause side effects on normal organs and show poor selective toxicity to tumors. It is therefore difficult to use these carcinostatic agents in an increased dosage with the expectation of stronger effects, because the side effects thereof are increased.

In contrast to the above conventional general theory, the present inventors made a drug into a macromolecular form by, for example, binding a biocompatible polymer to a carcinostatic agent, and then discovered the phenomenon that said drug shows a suppressed excretion (disappearance) from the blood through the kidney and a prolonged blood retention and leaks more selectively to the extravascular space at tumor sites owing to the enhanced vascular permeability (leakiness) and retention effect expressed in the solid tumor. The present inventors reported this phenomenon as an EPR (enhanced permeability and retention) effect (Non-Patent Documents 1 to 4) as a general concept.

The present inventors developed novel macromolecule-bound carcinostatic agents of pirarubicin (THP), for example, a polyhydroxypropylmethacrylamide (HPMA)-bound THP (P-THP) and a styrene-maleic acid copolymer (SMA)-bound THP (SMA-THP), and also macromolecule-bound conjugates of Zn-protoporphyrin (ZnPP) (P-ZnPP and SMA-ZnPP) (Patent documents 1 to 2). On the other hand, the present inventors revealed various pharmacological factors involved in the enhancement of the EPR effect. Examples of the factor include bradykinin, nitric oxide (NO), carbon monoxide, substances promoting their production, and ACE (angiotensin-converting enzyme) inhibitors (Non-Patent Documents 5 to 8). NO-releasing agents involved in the NO concentration of tumor sites or ACE inhibitors enhance the EPR effect in tumors by 2 to 3 times and also the tumor delivery of the above macromolecular drugs by 2 to 3 times (Non-Patent Documents 5 to 8).

CITATION LIST

Patent Documents

Patent Document 1: WO 2013/035750Patent Document 2: WO 2015/076312

Non-Patent Documents

Non-Patent Document 1: Y. Matsumura & H. Maeda, Cancer Res. (1986) 46, p. 6387-6392.Non-Patent Document 2: H. Maeda, Adv. in Enzyme Regulation (2001) 41, p. 189-207.Non-Patent Document 3: H. Maeda et al, Adv. Drug Deliv. Res (2013) 65, p. 71-79.Non-Patent Document 4: Proc. Japan Acad. Ser. B (2012) 88, p. 53-71.Non-Patent Document 5: T. Seki et al, Cancer Sci. (2009) 100, p. 2426-2430.Non-Patent Document 6: J. Fang et al, ADD Review (2011) 63, p. 136-151Non-Patent Document 7: H. Maeda, J. Control Release (2012) 164, p. 138-144Non-Patent Document 8: Fang et al, J. Control Release (2016) 223, p. 188-196

SUMMARY OF INVENTION

Technical Problem

Many macromolecular drugs show a relatively uniform molecular weight distribution due to particularly the formation of more complicated high order structure, or molecular interaction thereby. However, it may be difficult to maintain the proper high order structure in solution because of the formation of further complexes caused by strong interaction between the macromolecules, the inhibition of the complicated interaction between the side chain molecules thereof, or the like. The macromolecular drug molecules may also tend to associate with each other and form insoluble aggregates. Therefore, there are problems with the macromolecular drugs, such as low stability. Also, the macromolecules are often too strongly associated each other and thus do not disperse or dissolve in uniform aqueous solution.

Stability of molecular integrity is an especially important problem in micelle or liposome formulations, which are in the form of a macromolecule by intermolecular association. For example, if a micelle or liposome preparation has a problem with stability in a solution, there is a risk that the micelle-forming ability is lost or the encapsulated drug is released (liberated).

It is therefore desired to overcome a problem with solubility or instability in a solution of macromolecular drugs in order to improve the stability of such macromolecules in vivo and to maintain the tumor selectivity due to the EPR effect of the drugs. It is also important to enhance the EPR effect of these macromolecular drugs upon intravenous administration, because enhancement of EPR effect can result in increased anticancer effects and reduced side effects by the drugs.

In addition, many macromolecular drugs such as micelle formulations or the so-called nanomedicines have poor solubility, and this causes a problem in the bedside when a powder (solid) thereof is dissolved in an aqueous solvent to use it as an injection or the like.

Solution to Problem

As a result of intensive studies in view of the above problems, the present inventors have found that when a macromolecular drug (e.g., P-THP) is dissolved in an aqueous solvent to prepare an injection solution, the addition of a specific dissolution-enhancing and/or stabilizing agent to the solvent makes it possible to reduce the dissolution time of the macromolecular drug in the aqueous solvent, i.e., to promote the dissolution of the macromolecular drug, and to stabilize an ester bond, a hydrazone bond or a specific amide bond in the drug molecule in an aqueous solution, and also the addition of a specific dissolution-enhancing and/or stabilizing agent (e.g., arginine which is a substrate of NO synthase in vivo) makes it possible to enhance the EPR effect, etc. of the macromolecular drug as well as the above promoted dissolution and stabilization, thereby reaching to the present invention.

Accordingly, the present invention includes the followings.

[1] A pharmaceutical composition comprising a macromolecular drug, a dissolution-enhancing and/or stabilizing agent, and an aqueous solvent, wherein the dissolution-enhancing and/or stabilizing agent is at least one selected from the group consisting of

(1) proteins,

(2) synthetic polymers,

(3) sugars or sugar alcohols,

(4) inorganic salts,

(5) amino acids,

(6) phospholipids,

(7) aliphatic alcohols,

(8) medium-chain fatty acids, and

(9) mucopolysaccharides.

[2] The pharmaceutical composition according to [1], which has a pH of 7.0 to 8.0.

[3] The pharmaceutical composition according to [1] or [2], which is an injection.

[4] The pharmaceutical composition according to any one of [1] to [3], wherein the macromolecular drug is at least one selected from the group consisting of P-THP, P-ZnPP, SMA-THP, SMA-ZnPP, PEG-THP, and PEG-ZnPP.

[5] The pharmaceutical composition according to any one of [1] to [4], wherein the bond between the drug and the polymer in the macromolecular drug is at least one selected from the group consisting of an amide bond, an ester bond, a hydrazone bond, and a bond through Schiff base.
[6] The pharmaceutical composition according to [5], wherein the bond between the drug and the polymer in the macromolecular drug is a hydrazone bond.
[7] The pharmaceutical composition according to any one of [1] to [6], wherein the dissolution-enhancing and/or stabilizing agent is at least one selected from the group consisting of arginine and citrulline.
[8] The pharmaceutical composition according to any one of [1] to [7], which further comprises an EPR and/or antitumor effect enhancer.
[9] The pharmaceutical composition according to any one of [1] to [8], which is for carcinostatic or anti-tumor effect.
[10] A method for producing the pharmaceutical composition according to any one of [1] to [9], which comprises mixing the macromolecular drug, the dissolution-enhancing and/or stabilizing agent, and the aqueous solvent.
[11] A pharmaceutical composition comprising a macromolecular drug, and a dissolution-enhancing and/or stabilizing agent, wherein the dissolution-enhancing and/or stabilizing agent is at least one selected from the group consisting of
(1) proteins,
(2) synthetic polymers,
(3) sugars or sugar alcohols,
(4) inorganic salts,
(5) amino acids,
(6) phospholipids,
(7) aliphatic alcohols,
(8) medium-chain fatty acids, and
(9) mucopolysaccharides.
[12] The pharmaceutical composition according to [11], which further comprises an EPR and/or antitumor effect enhancer.
[13] A pharmaceutical composition comprising a macromolecular drug, and an EPR and/or antitumor effect enhancer, wherein the EPR and/or antitumor effect enhancer is at least one selected from the group consisting of
(1) nitroglycerin,
(2) arginine,
(3) hydroxyurea, and
(4) nitrosourea.
[14] The pharmaceutical composition according to [13], which further comprises a dissolution-enhancing and/or stabilizing agent.
[15] A method for enhancing dissolution and/or stabilizing a macromolecular drug, which comprises mixing the macromolecular drug with at least one dissolution-enhancing and/or stabilizing agent selected from the group consisting of
(1) proteins,
(2) synthetic polymers,
(3) sugars or sugar alcohols,
(4) inorganic salts,
(5) amino acids,
(6) phospholipids,
(7) aliphatic alcohols,
(8) medium-chain fatty acids, and
(9) mucopolysaccharides.

Effect of Invention

According to the pharmaceutical composition of the present invention, it is possible to markedly reduce the dissolution time of a macromolecular drug (e.g., P-THP) in an aqueous solvent, i.e., to promote dissolution of the macromolecular drug, and to significantly improve the stability of the macromolecular drug in a solution by a specific dissolution-enhancing and/or stabilizing agent. Furthermore, according to the present invention, it is possible to remarkably enhance the EPR effect, thus tumor delivery, anti-tumor effect, etc. of a macromolecular drug, in addition to the above effects, by a specific dissolution-enhancing and/or stabilizing agents.

Accordingly, when, for example, an anti-tumor agent is used as the drug, the pharmaceutical composition of the present invention becomes better antitumor pharmaceutical composition. When, for example, a fluorescent molecule is used as the drug, it is possible to promote the enhancement of EPR effect of the molecule to obtain a higher tumor accumulation thereof by administering it in the form of the present composition, compared with when administering it in the form of a single drug. The pharmaceutical composition of the present invention is thus very useful as a fluorescent probe for tumor.

According to the present invention, it is possible to provide, as a dosage form of a macromolecular drug, an injection easily dissolved in a specific aqueous solution or alike when used, which has an improved stability and shows an enhanced EPR effect, tumor delivery, anti-tumor effect or alike of the macromolecular drug, thereby showing an enhanced therapeutic effect of the macromolecular drug and a reduced side effect thereof.

In conclusion, according to the present invention, it is possible to significantly enhance the EPR effect, tumor delivery, antitumor effect, etc. of the macromolecular drug by administering it in combination with a specific EPR and/or antitumor effect enhancer.

