KR100802080B1 - pH SENSITIVE BLOCK COPOLYMER AND POLYMERIC MICELLE USING THE SAME - Google Patents

Abstract

The present invention (a) at least one compound selected from the group consisting of a compound comprising an ester group and a tertiary amine group and a compound comprising an amide group and a tertiary amine group or a copolymer of the compound; And (b) copolymerizing a compound having hydrophilicity or amphiphilicity to form a micelle.

The block copolymer of the present invention is formed by copolymerizing a biodegradable poly (β-amino ester) compound having a pH sensitivity and a hydrophilic polyethylene glycol-based compound, thereby changing according to the amphipathy and pH retained in itself. Ionization characteristics can form a micelle structure, which can be used as a target-oriented drug carrier according to pH changes in the body.

Block copolymers, micelles, pH sensitivity, drug delivery, diagnostics

Description

pH sensitive block copolymers and polymeric micelles using the same {pH SENSITIVE BLOCK COPOLYMER AND POLYMERIC MICELLE USING THE SAME}

FIG. 1 shows MPEG-A (Mn = 2000) in the pH sensitive block copolymers of Examples 1-3 prepared using polyethyleneglycol methyl ether acrylate (MPEG-A) and poly (β-amino ester) having a molecular weight of 2000; Is a graph showing the molecular weight control results of the block copolymer according to the change in the molar ratio of.

FIG. 2 shows block air with varying molar ratios of MPEG-A (Mn = 5000) in the pH sensitive block copolymers of Examples 4 and 5 prepared using MPEG-A and poly (β-amino ester) having a molecular weight of 5000. It is a graph which shows the molecular weight adjustment result of coalescence.

Figure 3 is a graph showing the molecular weight control results of the block copolymer according to the molar ratio of the diamine in the pH-sensitive block copolymer prepared in Examples 4, 6 to 9.

4 is a graph showing the behavior change of micelles according to the pH change of the block copolymers prepared in Examples 1 to 3.

FIG. 5 is a graph showing the change of the micelle behavior according to the pH change of the block copolymers of Example 4 and Example 10 prepared using piperazine and 4,4′-trimethylene dipiperidine as diamine compounds, respectively.

6 is a graph showing a change in critical micelle concentration (CMC) according to the pH change of the block copolymer prepared in Example 4.

7 is a graph showing the size change of the micelle according to the pH change of the block copolymer prepared in Example 4, it is a graph showing the micelle size at pH 8.01.

8 is a graph showing the size change of the micelle according to the pH change of the block copolymer prepared in Example 4, it is a graph showing the micelle size at pH 7.42.

9 is a graph showing the size change of the micelle according to the pH change of the block copolymer prepared in Example 4, it is a graph showing the micelle size at pH 7.23.

10 is a graph showing the micelle size change in the pH range of 6.3 to 8.0 of the block copolymer prepared in Example 4.

FIG. 11 is a graph showing changes in molecular weight over time at pH 7.4 of the block copolymers prepared in Examples 4 and 11.

12 is a graph showing the change in molecular weight over time at pH 7.4 of the block copolymer prepared in Examples 11 to 15, respectively.

FIG. 13 is a graph showing molecular weight changes with time at pH 7.4 of the block copolymers prepared in Examples 16 to 20, respectively. FIG.

The present invention relates to a biodegradable block copolymer for pH-sensitive drug carriers and a preparation method thereof, and a polymer micelle-type drug composition comprising the block copolymer, and more specifically, solubility in water according to pH. Nano-size polymers by self-assembly by inducing block copolymers of poly (β-amino ester) compounds having hydrophilic properties with poly (β-amino ester) compounds which do not form micelles due to self assembly In addition to being able to form micelles (particles) to be used as drug carriers, polyamides having slower biodegradation rate than poly (β-amino esters) have amide groups instead of ester groups in order to control biodegradation rates in vivo. Target-oriented drug room according to pH change in the body by introducing The only possible as well relates to a pH-sensitive block copolymer and a method for forming the biodegradable micelles (micelle) speed control is possible.

Micelles generally refer to thermodynamically stable and uniform spherical structures of amphiphilic, low molecular weight materials having both hydrophilic and hydrophobic groups at the same time. When a non-aqueous drug is dissolved and added to the compound having the micelle structure, the drug is present in the micelle, and the micelle can release the target-oriented drug in response to a change in temperature or pH in the body, thereby serving as a carrier for drug delivery. The possibility of application is very high.

Korean Patent Application No. 10-2001-0035265 describes the preparation of micelles using polyethylene glycol and biodegradable polymers. All of these materials have the advantage of being biocompatible because they are biodegradable, but they are difficult to deliver drugs at desired sites because they are not sensitive to specific changes such as changes in the body, such as pH.

On the other hand, the pH environment of the body generally shows a pH of 7.2 to 7.4, but the surrounding environment of abnormal cells such as cancer cells is known to exhibit a weak acidity of pH 6.0 to 7.2. Recently, research has been conducted to release drugs at pH 7.2 or lower in order to deliver drugs specifically to cancer cells.

U.S. Patent No. 6,103,865 discloses a polymer using sulfonamide, which is a material exhibiting pH sensitivity. The sulfonamide exhibits an acidity which becomes insoluble at pH 7.4 or below and ionized at pH 7.4 or above. In this case, since the opposite characteristics of the target for cancer cells are exhibited, it can be said that a compound having basicity is required for the target for cancer cells.

U.S. Patent No. 2004/0071654 A1 discusses the preparation of poly (β-amino esters) having basic properties, wherein poly (β-amino esters) are a class of poly (amino acid) esters in the main chain and tertiary. Having an amine group, there is an advantage of showing the ionization characteristics that the solubility in water is changed according to the pH.

The present inventors recognize that when poly (β-amino ester) or poly (amido amine) is used alone, it shows pH dependence but does not form micelles due to self assembly phenomenon. When a block copolymer is formed by copolymerizing a hydrophilic polyethyleneglycol-based compound in a mixture of β-amino ester) or poly (β-amino ester) and poly (amido amine), the prepared block copolymer is targeted at a specific pH. The present invention has been completed in view of the fact that it is possible to form a release micelle structure to be applied as a carrier for controlled release of a drug having a controlled biodegradation rate. In addition, in order to solve the problem of not being able to properly perform the function as a drug carrier due to the fast decomposition rate of poly (β-amino ester), poly (amidoamine), which is composed of amide groups instead of ester groups in the main chain, has a relatively low decomposition rate. Copolymerization with) successfully controlled to maintain the desired biodegradation rate.

Accordingly, the present invention provides a block air formed by polymerization of poly (β-amino ester) (PAE), poly (amido amine) (PAA) or a copolymer thereof (PAEA); and polyethylene glycol series compound (MPEGA). It is an object of the present invention to provide a polymer micelle (micelle) -type drug composition comprising the copolymer, a preparation method thereof, and the block copolymer.

The present invention (a) a bisacrylate or bisacrylamide-based first compound; (b) a second compound comprising a primary or secondary amine group; And (c) copolymerizing a polyethylene glycol based third compound having a molecular weight (Mn) in the range of 500 to 5000, wherein the hydrophilic block derived from the third compound (c) in the formed block copolymer, and the first compound (a) and By adjusting the molecular weight ratio (parts by weight) of the hydrophobic blocks derived from the second compound (b) in the range of 10 to 40:60 to 90, and including tertiary amine groups ionized in the range of pH 6.0-7.0 between these blocks, Provided is a method for preparing a pH block copolymer capable of forming micelles by reversible self-assembly in the range of 7.2 to 7.4.

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EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention is not only sensitive to pH changes in the body, but also specific pH, by copolymerizing a polyethylene glycol-based compound having hydrophilicity with a pH-sensitive compound such as poly (β-amino ester), poly (amido amine) or a copolymer thereof. It is possible to form a micelle structure in the region, and to provide a block copolymer having a controlled biodegradation rate in vivo of the formed micelle.

The pH sensitive micelle of the present invention forms stable micelles at a specific pH, such as pH 7.2 to 7.4, which is the pH range of normal cells in the body, and collapses the micelle structure when it is below the pH range 7.2 indicated by abnormal cells such as cancer cells. It can be used as a carrier for target release drug release to cells. That is, at low pH (below pH 7.0) due to increased ionization of tertiary amines present in poly (β-amino esters) (PAE), poly (amido amines) (PAA), or mixed copolymers thereof (PAEA) The entire PAE (or PAA, PAEA) becomes water-soluble and cannot form micelles, and at pH 7.4, the ionization degree of PAE (or PAA, PAEA) decreases and shows hydrophobic characteristics to form micelles by self-assembly. .

In addition, the block copolymer capable of forming the pH-sensitive micelles can be applied to diagnostic applications such as diagnostic imaging by delivering substances to abnormal cells, as well as in gene transfer and drug delivery fields. have.

Additionally, in the present invention, micelles were formed in the range of pH 7.2 to 7.4, which is the same as normal body conditions, and cancer cell target-oriented micelles in which micelles collapsed at pH 7.2 or lower, such as cancer cells, were applied. By appropriately modifying the constituents, their molar ratios, molecular weights and / or functional groups in the block, one can design a target-oriented micelle not only for cancer cells but also for genetic variation or other applications and usefully apply it.

Furthermore, in the present invention, the pH-sensitive block copolymer micelles may be prepared by variously controlling the formation conditions of the pH-sensitive block copolymers, such as the constituents of the above-described block copolymers, their molar ratios, molecular weights and / or functional groups in the block. The rate of biodegradation in vivo can be easily controlled, thereby allowing targeted drug delivery to appropriate body locations where drug delivery should occur.

One of the constituents of the block copolymer forming the pH sensitive micelle according to the present invention can be used without limitation the conventional hydrophilic biodegradable compounds known in the art, in particular polyethylene glycol series compounds are preferred. More preferably, a polyethylene glycol-based compound has a single functional group (monofunctional) such as acrylate or methacrylate at the terminal, and an example thereof includes a compound represented by the following Chemical Formula 1 in which a molecular terminal portion is substituted with an acrylate.

Wherein R is a hydrogen atom or an alkyl group of 1 to 6 carbon atoms, where x is a natural number in the range of 1 to 10,000.

The alkyl group means a linear or branched lower saturated aliphatic hydrocarbon, for example, methyl, ethyl, n -propyl, isopropyl, n -butyl, s -butyl, isobutyl, t -butyl and n -pentyl groups Etc.

The molecular weight (Mn) of the polyethylene glycol-based compound is not particularly limited, but is preferably in the range of 500 to 5000. When the molecular weight (Mn) of the polyethylene glycol-based compound is out of the above range, for example, less than 500 and more than 5000, it is difficult to control the molecular weight of the final block copolymer, and it is easy to form micelles using the block copolymer. Not. That is, when the molecular weight is less than 500, the length of the hydrophilic block at a certain pH is too short to self-assembly due to hydrophilicity / hydrophobicity is not only difficult to form micelles, even if formed is dissolved in water and easily collapse. In addition, when the molecular weight exceeds 5,000, the block length becomes too large relative to the molecular weight of the hydrophobic compound, so that the balance of hydrophilicity / hydrophobicity may be broken and micelles may not be formed at a specific pH and may precipitate.

The other component of the block copolymer forming the pH sensitive micelle according to the present invention is a compound having both hydrophobicity and pH sensitivity, and non-limiting examples thereof include poly (β-amino ester) (PAE), poly (ami) Amine) (PAA) or mixed copolymers thereof (PAEA) and the like.

The PAE, PAA, and PAEA have ionization properties of varying solubility in water according to pH due to tertiary amine groups present in themselves, thereby forming and / or decaying micelle structures according to pH changes in the body as described above. Can be. The compounds may be prepared according to conventional methods known in the art, and for example, may be obtained by polymerizing an amine-based compound with a double bond bisacrylate compound or bisacrylamide compound through a Mitchell reaction. have.

The bisacrylate compound used herein may be represented by the following Chemical Formula 2, and non-limiting examples thereof include ethylene glycol diacrylate, 1,4-butane diol diacrylate, and 1,3-butane diol diacryl. Rate, 1,6-hexane diol diacrylate, 1,6-hexane diol ethoxylate diacrylate, 1,6-hexane diol propoxylate diacrylate, 3-hydroxy-2,2- Dimethylpropyl3-hydroxy-2,2-dimethylpropionate diacrylate, 1,7-heptane diol diacrylate, 1,8-octane diol diacrylate, 1,9-nona diol Diacrylates, 1,10-decane diol diacrylates or mixtures thereof.

In the above formula, R ₃ is an alkyl group having 1 to 30 carbon atoms.

Bisacrylamide-based compound may be represented by the following formula (3). In this case, non-limiting examples of diacrylamide include N, N'-methylene bisacrylamide (MDA), N, N'-ethylene bisacrylamide or mixtures thereof. Examples of the diacrylamide compound and the amine compound include 4-aminomethyl piperidine (AMPD), N-methyl ethylenediamine (MEDA), and 1- (2-aminoethyl) piperidine (AEPZ). Can be prepared according to conventional methods known in the art, such as the Mitchell reaction.

In Formula 3, R is an alkyl group having 1 to 20 carbon atoms.

In addition, the amine-based compound may be used without limitation as long as it has an amine group, and in particular, a primary amine represented by the following formula (4), a secondary amine-containing diamine compound represented by the formula (5) or a mixture thereof is preferable.

H ₂ NR ₁

In the above formula, R ₁ and R ₂ are alkyl groups having 1 to 20 carbon atoms.

Non-limiting examples of such primary amine compounds include 3-methyl-4- (3-methylphenyl) piperazine, 3 methylpiperazine, 4- (bis- (fluorophenyl) methyl) piperazine, 4- (ethoxy Carbonylmethyl) piperazine, 4- (phenylmethyl) piperazine, 4- (1-phenylethyl) piperazine, 4- (1,1-dimethoxycarbonyl) piperazine, 4- (2- (bis- (2-propenyl) amino) ethyl) piperazine, methylamine, ethylamine, butylamine, hexylamine, 2-ethyl hexylamine, 2-piperidin-1-ethylamine, C-aziridin-1-yl- Methylamine, 1- (2-aminoethyl) piperazine (1- (2-aminoethyl) piperazine), 4- (aminomethyl) piperazine, N-methylethylenediamine (N- methylethylenediamine, N-ethylethylenediamine, N-hexylethylenediamine, N-hexylethylenediamine, pycoliamine, adenine, and the like, and the ratio of the secondary amine-containing diamine compound Restrictive examples include piperazine, piperidine, blood Pirrolidine, 3,3-dimethylpiperidine, 4,4'-trimethylene dipiperidine, N, N'-dimethyl ethylene diamine, N, N'-diethyl Ethylene diamine, imidazolidine or diazepan.

In preparing compounds exhibiting pH sensitivity, such as PAE, PAA, and PAEA, the reaction molar ratio of the bisacrylate compound or bisacrylamide compound and the amine compound is preferably in the range of 1: 0.5 to 2.0. When the molar ratio of the amine compound is less than 0.5 or more than 2.0, the molecular weight of the polymer to be polymerized becomes 1000 or less, making it difficult to form micelles.

The pH-sensitive block copolymer of the present invention formed through copolymerization of the aforementioned hydrophilic polyethyleneglycol-based compound with a pH-sensitive compound may be represented by the following Chemical Formulas 6, 7, or 8.

(I)

(I)

(Ⅱ)

(Ⅱ)

(Ⅲ)

(Ⅲ)

Wherein R is a hydrogen atom or an alkyl group of 1 to 6 carbon atoms, where x is a natural number in the range of 1 to 10,000;

R ₁ and R ₂ are alkyl groups having 1 to 20 carbon atoms;

R ₃ is an alkyl group having 1 to 30 carbon atoms;

R ₄ is an alkyl group having 1 to 20 carbon atoms;

y is a natural number ranging from 1 to 10,000.

The block copolymer represented by Formula 6, 7, or 8 may form or decay micelles according to pH change due to the aforementioned amphipathicity and pH sensitivity, and preferably, micelles when the pH is in the range of 7.0 to 7.4. When the pH ranges from 6.5 to 7.0, the micelles will collapse. In particular, since the block copolymer of the present invention has an advantage of exhibiting excellent sensitivity within a pH range of ± 0.2, satisfactory results may be obtained in applications requiring sensitivity to pH changes in the body, such as drug release carriers or diagnostic applications. Can be derived.

The block copolymer of the present invention may further include other conventional units in the art, in addition to the hydrophilic polyethyleneglycol-based compound and the pH-sensitive compound, as long as it maintains pH sensitivity and maintains physical properties forming micelles. It belongs to the scope of the present invention.

The molecular weight range of the block copolymer is not particularly limited, but is preferably in the range of 1,000 to 20,000. When the molecular weight is less than 1,000, the block copolymer micelles are difficult to form at a specific pH, and even if formed, are dissolved in water and easily collapsed. In addition, when the molecular weight exceeds 20,000, the balance of hydrophilicity / hydrophobicity may be broken and micelles may not be formed at a specific pH and may precipitate.

The content of the polyethylene glycol-based block (A) in the pH-sensitive block copolymer according to the present invention is not particularly limited, but 5 to 95 parts by weight is appropriate, preferably 10 to 40 parts by weight. When the content of the polyethylene glycol-based block is less than 5 parts by weight, the block copolymer may precipitate without forming micelles. When the content of the polyethylene glycol-based blocks exceeds 95 parts by weight, the blocks forming the micelles are too small to form micelles. Will exist. In addition, the block copolymer may be an AB-type double block copolymer by controlling the reaction molar ratio of polyethylene glycol-based compounds and pH sensitive compounds, such as PAE, PAA, or PAEA; It is possible to form various block forms of triblock copolymers of ABA or BAB type or higher.

The pH sensitive block copolymers according to the present invention can be prepared according to conventional methods known in the art, and examples thereof can be synthesized by the route of Scheme 1, 2 or Scheme 3 below.

For example, a polyethylene glycol (MPEG-A) having a acrylate end group, a primary amine, and a bisacrylate may be used to perform a copolymerization reaction commonly known in the art. do. At this time, the primary amine and bisacrylate form a poly (β-amino ester) by an addition reaction called Michael reaction, and the formed poly (β-amino ester) is copolymerized with a polyethyleneglycol-based compound having an acrylate functional group at its terminal. To prepare a block copolymer represented by the formula (6).

For example, a block copolymer represented by Chemical Formula 7 using polyethylene glycol (MPEG-A) having a acrylate end group, a secondary amine-containing diamine compound, and bisacrylate may be used. In the preparation of the block copolymer, chloroform, tetrahydrofuran, dimethyl sulfoxide, dimethyl formamide, methylene chloride, and the like may be used as the organic solvent.

For example, a copolymerization commonly known in the art using polyethylene glycol (MPEG-A) having an acrylate end group, a primary or secondary amine, and bisacrylamide may be used. Proceed with the reaction. At this time, the primary or secondary amine and the bisacrylate form a poly (amido amine) by an addition reaction called Michael reaction, and the poly (amido amine) formed is a polyethylene glycol-based compound having an acrylate functional group at its terminal. By copolymerizing it may be prepared a pH-sensitive block copolymer represented by the formula (8).

Meanwhile, in the present invention, the gel permeation chromatography (GPC) was used to measure the molecular weight of the block copolymer synthesized as described above, and the fluorescence spectrometer was used to measure the concentration change and the change in the size of the micelle according to the pH change. And DLS (Dynamic Light Scattering) were used. Indeed, the above-mentioned assays could confirm the applicability as pH sensitive micelles.

In addition, the present invention (a) the above-described block copolymer to form a micelle according to the pH change; And (b) provides a polymer micelle-type drug composition comprising a bioactive material that can be encapsulated in the block copolymer.

The polymer micelle-type drug composition forms micelles when injected into the body, and when micelles reach a locally low pH, such as cancer cells, micelles collapse, resulting in target-oriented drug delivery through the release of encapsulated supported drugs. Can be.

Bioactive substances that can be encapsulated in the polymer micelle type block copolymer of the present invention can be used without particular limitation, and non-limiting examples thereof include anticancer agents, antibacterial agents, steroids, anti-inflammatory drugs, sex hormones, immunosuppressants, antiviral agents , Anesthetics, antiemetics or antihistamines. In addition to the aforementioned components, it may also include conventional additives known in the art such as excipients, stabilizers, pH adjusters, antioxidants, preservatives, binders or disintegrants and the like.

The method for preparing a polymer micelle according to the present invention may be used alone or in combination with a method such as agitation, heating, ultrasonic scanning, solvent evaporation using an emulsification method, matrix formation, or dialysis using an organic solvent.

The diameter of the prepared polymer micelles is not particularly limited, but is preferably in the range of 10 to 1000 nm. In addition, the polymer micelle drug composition may be formulated in the form of oral or parenteral preparations, and may be prepared by intravenous, intramuscular or subcutaneous injection.

The present invention also provides a method of using the pH sensitive block copolymer as a carrier for drug delivery or disease diagnosis. In this case, the material contained in the block copolymer is not particularly limited as long as it is a material for treating, preventing or diagnosing a disease.

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Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

[ Example  1 to 20. pH  Sensitive block copolymer synthesis]

Example  One. Polyethylene glycol - Poly (β-amino ester) block copolymer ( PAE ) Produce

Polyethylene glycol methyl ether (MPEG2000, Mn = 2000) and acryloyl chloride were reacted under methylene chloride added with triethylamine (TEA), extracted with dilute hydrochloric acid solution and precipitated in n-hexane to precipitate hydrophilic polyethylene glycol. Methyl ether acrylate (MPEG2000-A, Mn = 2000) was prepared. 0.1 mole of MPEG2000-A and 1 mole of 4,4'-trimethylene dipiperidine and 1 mole of 1,6-hexane diol diacrylate were placed in a two-necked round flask with nitrogen diamine. In this case, chloroform was used as a reaction solvent, and reacted at 50 ° C. for 48 hours to prepare polyethylene glycol-poly (β-amino ester) block copolymer (MPEGA-PAE) having a molecular weight (Mp) of 7700.

Example  2

An MPEGA-PAE block copolymer having a molecular weight (Mp) of 4800 was prepared in the same manner as in Example 1, except that 0.2 mol of polyethylene glycol methyl ether acrylate (MPEG2000-A) was used instead of 0.1 mol. .

Example  3

An MPEGA-PAE block copolymer having a molecular weight (Mp) of 4400 was prepared in the same manner as in Example 1, except that 0.3 mol of polyethylene glycol methyl ether acrylate (MPEG2000-A) was used instead of 0.1 mol. .

Example  4

An MPEGA-PAE block copolymer having a molecular weight (Mp) of 13500 was prepared in the same manner as in Example 1, except that 0.1 mole of MPEG5000-A prepared using MPEG5000 instead of MPEG2000 was used.

Example  5

An MPEGA-PAE block copolymer having a molecular weight (Mp) of 12500 was prepared in the same manner as in Example 1, except that 0.4 mol of MPEG5000-A prepared using MPEG5000 instead of MPEG2000 was used.

Example  6

The molecular weight (Mp) was carried out in the same manner as in Example 1, except that 0.1 mol of MPEG5000-A prepared using MPEG5000 instead of MPEG2000 was used, and 0.8 mol of 4,4'-trimethylene dipiperidine was used. This 8800 MPEGA-PAE block copolymer was prepared.

Example  7

The molecular weight (Mp) was carried out in the same manner as in Example 1, except that 0.1 mol of MPEG5000-A prepared using MPEG5000 instead of MPEG2000 was used, and 1.1 mol of 4,4'-trimethylene dipiperidine was used. This 20000 MPEGA-PAE block copolymer was prepared.

Example  8

Molecular weight (Mp) was carried out in the same manner as in Example 1, except that 0.1 mole of MPEG5000-A prepared using MPEG5000 instead of MPEG2000, and 1.3 mole of 4,4'-trimethylene dipiperidine were used. This 7900 MPEGA-PAE block copolymer was prepared.

Example  9

The molecular weight (Mp) was carried out in the same manner as in Example 1, except that 0.1 mol of MPEG5000-A prepared using MPEG5000 instead of MPEG2000 was used, and 1.5 mol of 4,4'-trimethylene dipiperidine was used. This 6900 MPEGA-PAE block copolymer was prepared.

Example  10

The molecular weight (Mp) was carried out in the same manner as in Example 1, except that 0.1 mole of MPEG5000-A prepared using MPEG5000 instead of MPEG2000 was used, and piperazine was used instead of 4,4'-trimethylene dipiperidine. 6200 MPEGA-PAE block copolymer was prepared.

Example  11

In order to control the biodegradation rate of the MPEG-PAE block copolymer, 0.1 mol of MPEG5000-A prepared using MPEG5000 was used, and 1 mol of piperazine and 0.8 mol of 1,6-hexane diol diacrylate were used as an amine compound. As a biodegradation rate regulator, 0.2 mole of N, N'-methylene bisacrylamide was added as a diacrylamide component to prepare an MPEGA-PAEA block copolymer having a molecular weight of 13,200.

Example  12

The molecular weight was the same as in Example 11 except that 0.4 mole of N, N'-methylene bisacrylamide was used as the diacrylamide component as a biodegradation rate regulator in 0.6 mole of 1,6-hexane diol diacrylate. An MPEGA-PAEA block copolymer having a (Mp) of 13,700 was prepared.

Example  13

Molecular weight was carried out in the same manner as in Example 11, except that 0.4 mol of 1,6-hexane diol diacrylate was used with 0.6 mol of N, N'-methylene bisacrylamide as the diacrylamide component as a biodegradation rate regulator. An MPEGA-PAEA block copolymer having a (Mp) of 13,400 was prepared.

Example  14

Molecular weight was carried out in the same manner as in Example 11, except that 0.8 mol of N, N'-methylene bisacrylamide was used as the diacrylamide component as a biodegradation rate regulator in 0.2 mol of 1,6-hexane diol diacrylate. An MPEGA-PAEA block copolymer having a (Mp) of 13,300 was prepared.

Example  15

MPEGA-PAA block having a molecular weight of 13,800 by using 0.1 mole of MPEG5000-A prepared using MPEG5000 and adding 1 mole of piperazine as an amine compound and 1 mole of N, N'-methylene bisacrylamide as diacrylamide compound Copolymers were prepared.

Example  16

An MPEGA-PAEA block copolymer having a molecular weight of 10,200 was prepared in the same manner as in Example 11, except that 0.1 mole of MPEG2000-A prepared using MPEG2000 instead of MPEG5000-A 0.1 was used.

Example  17

0.1 mol of MPEG2000-A prepared using MPEG2000 was used, and 0.4 mol of N, N'-methylene bisacrylamide was used as diacrylamide as a biodegradation rate regulator in 0.6 mol of 1,6-hexane diol diacrylate. Except for the use, the same procedure as in Example 11 was carried out to prepare a MPEGA-PAEA block copolymer having a molecular weight (Mp) of 10,400.

Example  18

0.1 mol of MPEG2000-A prepared using MPEG2000 was used, and 0.6 mol of N, N'-methylene bisacrylamide was used as diacrylamide as a biodegradation rate regulator in 0.4 mol of 1,6-hexane diol diacrylate. Except for using the same as in Example 11 to prepare a MPEGA-PAEA block copolymer having a molecular weight (Mp) of 10,700.

Example  19

0.1 mol of MPEG2000-A prepared using MPEG2000 was used, and 0.8 mol of N, N'-methylene bisacrylamide was used as diacrylamide as a biodegradation rate regulator in 0.2 mol of 1,6-hexane diol diacrylate. Except for using the same as in Example 16 to prepare a MPEGA-PAEA block copolymer having a molecular weight (Mp) of 10,300.

Example  20

MPEGA-PAA block having a molecular weight of 10,600 by using 0.1 mole of MPEG2000-A prepared using MPEG2000 and adding 1 mole of piperazine as an amine compound and 1 mole of N, N'-methylene bisacrylamide as diacrylamide compound Copolymers were prepared.

[ Comparative example  1 to 2]

Comparative example  One

An MPEGA-PAE block copolymer having a molecular weight (Mp) of 8000 was prepared in the same manner as in Example 1, except that 0.1 mole of MPEG500-A prepared using MPEG400 instead of MPEG2000 was used.

As a result of observing the behavior according to the pH change using the prepared MPEGA-PAE block copolymer, it was confirmed that the block copolymer did not form micelles. As described above, the hydrophilic block is too short at a certain pH to prevent self-assembly due to hydrophilicity / hydrophobicity, which is not only difficult to form micelles, but also to dissolve and collapse in water even if formed. It is disproving.

Comparative example  2

An MPEGA-PAE block copolymer having a molecular weight (Mp) of 14500 was prepared in the same manner as in Example 1, except that 0.1 mole of MPEG6000-A prepared using MPEG6000 instead of MPEG2000 was used.

As a result of observing the behavior according to the pH change using the MPEGA-PAE block copolymer, it was confirmed that the block copolymer of Comparative Example 2 does not form micelles as in Comparative Example 1. This means that the block length becomes too large relative to the molecular weight of the hydrophobic compound, so that the hydrophilic / hydrophobic balance is broken and micelles cannot be formed at a specific pH and precipitate.

Experimental Example  One. pH  Molecular Weight Measurement of Sensitive Block Copolymers

In order to measure the molecular weight of the pH sensitive block copolymer prepared according to the present invention, the following analysis was carried out.

MPEGA-PAE, MPEGA-PAA or MPEGA-PAEA block copolymers prepared in Examples 1 to 15 were used, and Gel Permeation Chromatography (GPC, Waters, Inc.) analysis was performed to investigate their molecular weight control possibilities.

As a result of performing molecular weight analysis of the MPEGA-PAE block copolymers prepared in Examples 1 to 5, it is possible to control the molecular weight of the final copolymer using MPEG2000-A (see FIG. 1), but MPEG5000-A It was found that when using the molecular weight control of the final copolymer is not easy (see Fig. 2).

In order to confirm the molecular weight controllability of the final copolymer prepared from MPEG5000-A, the MPEGA-PAE block copolymers of Examples 4, 6 to 9, in which MPEG-A and bisacrylate content were fixed and only the diamine content was changed, As a result of molecular weight analysis, the use of MPEG5000-A not only can control the molecular weight of the final copolymer but also control of the final copolymer having a di- or tri-block structure. It could be confirmed (see FIG. 3). In fact, a copolymer having a molecular weight of about 13,000 was synthesized when the amount of diamine added was 1 mol, which is presumed to be a diblock copolymer in which MPEG having a molecular weight of 5000 and PAE having a molecular weight of 8000 were combined. In addition, when the amount of diamine added increased to 1.1 moles, the molecular weight increased to about 19,000 even though the molecular weight had to be reduced due to an imbalance in molar ratio during polymerization. It can be seen that triblock copolymers of MPEG-A, PAE, and MPEG-A have been prepared. However, when the amount of diamine added increased to 1.3 moles and 1.5 moles, the molecular weight of the block copolymer decreased, which can be judged to be due to the imbalance of molar ratios having a great effect on the degree of polymerization.

Experimental Example  2. pH  According to the change Micelles  Change measurement

In order to observe the behavior of the pH-sensitive block copolymer micelle prepared according to the present invention according to the pH change, the following experiment was carried out.

Block copolymers of various molecular weights prepared in Examples 1-4 and 10 were used. Since a change in the behavior of micelles cannot be known directly through a fluorescence spectrometer, pyrene, a hydrophobic light emitting material, was used.

A buffer solution of pH 6.0 containing 10 ^-6 M pyrene was prepared, and each copolymer prepared in Examples 1 to 4 and 10 was dissolved at a concentration of 1 mg / ml, and then the pH of the solution was adjusted to pH 8.0. Raised. Thereafter, 5 M aqueous hydrochloric acid solution was added dropwise to change the pH to a range of 5.5 to 8.0. Accordingly, the change in energy emitted due to the change in the concentration of micelles was measured through a fluorescence spectrometer.

First, when the block copolymers of Examples 1, 2 and 3 prepared using polyethylene glycol having a molecular weight of 2000 were measured to change their behavior according to pH change, the poly (β-amino ester) block copolymer As the molecular weight of was increased, the pH range in which the micelles collapsed was slightly changed (see FIG. 4). This is due to a change in the fraction of the hydrophobic poly (β-amino ester) block and the hydrophilic polyethylene glycol block in the prepared block copolymer, the ionization degree is slightly different due to the pH change, the behavior range of the micelle is changed it means.

In addition, as a result of measuring the behavior of the copolymer micelles prepared using different diamine compounds in Examples 4 and 10, it was found that the copolymers of Example 4 were collapsed in the narrower pH range. (See Figure 5). This may be due to the different ionization tendencies of piperazine and 4,4'-trimethylene dipiperidine. Therefore, when 4,4'-trimethylene dipiperidine is used, it was confirmed that the collapse of the micelle was made in a narrower range, and thus it could be used as a material more sensitive to pH change.

Experimental Example  3. Block copolymer pH In accordance Micelles  Change measurement

In order to observe the change in specific pH of the pH sensitive block copolymer micelles prepared according to the present invention, the following experiments were carried out.

3-1. CMC ( Critical Micelle Concentration ) Measure

The copolymer prepared in Example 4 was measured for CMC at pH 7.01, pH 7.24, pH 7.4.

As a result, the block copolymer of the present invention formed a stable micelle at pH 7.4, it was confirmed that no micelle was formed at pH 7.0 (see Fig. 6). This is due to an increase in the degree of ionization of the tertiary amine present in the poly (β-amino ester) at low pH (below pH 7.0), resulting in the entire PAE becoming water soluble, making the copolymer unable to form micelles. This means that the degree of ionization of the crystal is reduced to form a micelle by self-assembly by exhibiting hydrophobic characteristics.

3-2. Micelles  Size measurement

The copolymer prepared in Example 4 was measured for size change of micelles using DLS (Dynamic Light Scattering) at pH 8.01, pH 7.42, pH 7.23, pH 6.68, and pH 6.30.

As a result of the experiment, it can be seen that micelles having a certain size exist at pH 7.0 or above (see FIGS. 7, 8 and 9), but below pH 7.0, poly (β-aminoester) is completely ionized to form micelles at all. It was confirmed that not (see Fig. 10).

As a result, the pH-sensitive block copolymer of the present invention can be confirmed that the polymer micelle (micelle) can be formed and collapsed through the reversible self-assembly according to the amphipathic and pH changes present in the copolymer. there was.

Experimental Example  4. Block Copolymer Micelles pH Rate of biodegradation

In order to observe the change in specific pH of the pH sensitive block copolymer micelles prepared according to the present invention, the following experiments were carried out.

The copolymer of Example 4 prepared using a poly (β-amino ester) having an ester group in the main chain and having a relatively high biodegradation rate in vivo, and a poly (amido amine) having a relatively low biodegradation rate in the body having an amide group in the main chain The copolymer prepared in Example 11 prepared was used. In addition, the air of Examples 11 to 20 prepared by adjusting the components constituting the copolymer of Example 11, such as an amine compound, the content of poly (amido amine) which is a biodegradation rate regulator, and their composition ratio, etc. Coalescing was used.

As a result of measuring the molecular weight change over time at each pH 7.4, the block copolymer micelles of Example 4 showed that the molecular weight was reduced by more than half before 30 hours, so that biodegradation of micelles proceeded rather quickly. On the other hand, the block copolymer micelle of Example 11 was found to have a slow biodegradation rate (see FIG. 11). In addition, as a result of measurement using the block copolymer micelles of Examples 11 to 20, when the content of the components constituting the block copolymer micelle, the molar ratio thereof, etc., micelles exhibit various decomposition rates in vivo. It was confirmed that it is easy to adjust so that (see Figure 12). Therefore, the pH sensitive block copolymer of the present invention is a kind of poly (β-amino acid), and can easily control the desired biodegradation rate through a copolymer with poly (amido amine), which has a relatively low biodegradation rate in vivo. We can see that it can be designed to sustain the rate of biodegradation.

The block copolymer of the present invention polymerizes a hydrophilic polyethyleneglycol-based compound to poly (β-amino ester) and poly (amidoamine) compounds which have solubility in water depending on pH but fail to form micelles due to self-assembly. By forming a pH-sensitive block copolymer, not only retains pH sensitivity, but also reversibly forms a polymer micelle by self-assembly, which can be used as a drug-director and a diagnostic agent targeted for pH change in the body.

Claims (1)

(a) a bisacrylate or a bisacrylamide series first compound; (b) a second compound comprising a primary or secondary amine group; And (c) copolymerizing a polyethylene glycol based third compound having a molecular weight (Mn) in the range of 500 to 5000, The molecular weight ratio (parts by weight) of the hydrophilic block derived from the third compound (c) and the hydrophobic block derived from the first compound (a) and the second compound (b) in the formed block copolymer is 10 to 40:60 to To the 90 range, By including tertiary amine groups ionized in the range of pH 6.0-7.0 between these blocks, A method for preparing a pH block copolymer capable of forming micelles by reversible self-assembly in a pH range of 7.2 to 7.4.

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