KR20100097075A - Ubiquitous injectable, thermo-reversible gel for hydrophobic and hydrophilic drug delivery - Google Patents

Abstract

PURPOSE: A temperature-sensitive gel which is able to transfer hydrophobic and hydrophilic drugs is provided to use in drug delivery system and to ensure biocompatibility and biodegradability. CONSTITUTION: A temperature-sensitive gel for drug delivery contains temperature-reversible polysaccharide and pluronic synthetic polymer. The drug is hydrophilic or hydrophobic. The content ratio of the of the polysaccharide:pluronic is 1:0.1-1:1 in case of hydrophilic drug. The content ratio of the polysaccharide:pluronic is 1:0.01-1:0.1. The temperature-reversible polysaccharide is methylcellulose. A composition for sustained release drug delivery contains the temperature-sensitive gel and hydrophilic and/or hydrophobic drug.

Description

Ubiquitous Injectable, Thermo-Reversible Gel for Hydrophobic and Hydrophilic Drug Delivery}

The present invention relates to a drug delivery system. More specifically, the present invention relates to a ubiquitous injectable thermosensitive gel capable of hydrophobic and hydrophilic drug delivery.

In recent years, in situ-forming systems have been reported for a variety of biological medical uses, including drug delivery and tissue culture treatment (RL Dunn et al., Biodegradable in-situ forming implants and methods of producing the same, US Patent 4 ( 1990) 938-763; BO Haglund et al., J. Control.Release 41 (1996) 29-235; and Y. An et al., J. Control.Release 64 (2000) 205-215).

For example, several mechanisms, such as solvent exchange, pH change, ultraviolet (UV) irradiation, ion crosslinking, and temperature transition, have made it possible to reach in situ gel formation. Negative temperature sensitive polymers with a lower critical solution temperature (LCST) or temperature-reversible hydrogels exhibiting a reversible gel-sol transition behavior upon heating or cooling are the most suitable for stimulus-sensitive polymer systems for drug delivery. It is a commonly studied field.

Although several synthetic polymers have been reported to exhibit temperature-reversible gelling behavior at body temperature and have been used for drug delivery, there are still problems related to their biocompatibility and biodegradability.

As a technique for conventional drug delivery, drug delivery technology using a polymer, drug delivery technology using a protein drug, a drug delivery system and a gel depot drug delivery system using a PLGA-PEG-PLGA synthetic polymer are known.

However, these techniques have a problem in that the biocompatibility of the synthetic polymer is insufficient, toxic substances remain, and the process is complicated. In addition, the gelling temperature (gelling temperature) is higher than the body temperature, due to the high molecular weight not only decreases the discharge efficiency, it is not easy to control the discharge period of the drug, in the presence of excess body fluid gel form by dilution It will cause a problem such as disappear.

Thus, it is suitable for both hydrophilic and hydrophobic drug delivery, while improving the problem of biocompatibility and degradation ability of the synthetic polymer, while allowing the single-dose administration of the drug while increasing the stability of the drug, and to the tissue near the target of the drug There is an urgent need for the development of new drug delivery systems that can be injected to increase drug delivery efficiency to targets.

Accordingly, the inventors of the present invention have shown that the biocompatibility and biodegradability can be improved through a temperature-sensitive gel for drug delivery containing methylcellulose, salt salt, and a small amount of Pluronic synthetic polymer, which are small molecular weight natural polymers. The present invention has been completed by discovering.

It is an object of the present invention to provide thermosensitive gels for hydrophobic and hydrophilic drug delivery, which are highly biocompatible and biodegradable.

It is another object of the present invention to provide a sustained release composition for a drug delivery system that allows a drug to be released slowly in the body when injected into a specific site in the body.

In order to achieve the above object, the present invention provides a thermosensitive gel for drug delivery, containing a salt salt, a temperature reversible polysaccharide having a molecular weight of 10000 ~ 20000 Daltons and Pluronic synthetic polymer.

In the drug delivery gel according to the present invention, the thermoreversible polysaccharide having a molecular weight of 10000 to 20000 Daltons is a cellulose derivative selected from the group consisting of methylcellulose, hydroxypropylmethylcellulose, ethylhydroxyethylcellulose, carrageenan and scelloglucan. And most preferably methylcellulose.

In addition, the salting out salt to be used is Hope Meister series _{^{(SO 4 2-, HPO 4 2-}} , F -, Cl -, Br -, NO 3 -, I -, ClO 4 -, SCN -) or lyophilic series (Al ³⁺ , Ca ²⁺ , Mg ²⁺ , K ⁺ , NH ₄ ⁺ , Na ⁺ , Li ⁺ , PO ₄ ^3- , SO ₄ ^2- , Cl ⁻ , No ₃ ⁻ ) Preferably SO ₄ ^2- .

The temperature sensitive gel of the present invention may further comprise a solubilizer. As a solubilizer used to increase the solubility of hydrophobic drugs, preferred in the present invention are carbohydrate-based cyclodextrins.

The drug that can be used in the thermosensitive gel of the present invention may be any hydrophilic drug or any hydrophobic drug. It is also possible to load any hydrophilic and hydrophobic drugs simultaneously.

When the drug is a hydrophobic drug, the content ratio of polysaccharide: pluronic is 1: 0.1 to 1: 1, and when the drug is a hydrophilic drug, the content ratio of polysaccharide: pluronic is 1: 0.01. ~ 1: 0.1 characterized in that. Each of these ranges is such that the Pluronic synthetic polymer is used only for loading (sealing) of hydrophobic drugs or in the case of hydrophilic drugs to form a more dense gel.

When the hydrophilic drug and the hydrophobic drug are loaded at the same time, the content ratio of polysaccharide: pluronic is 1: 0.05 to 1: 0.5. The above range is a range capable of effective encapsulation of hydrophobic drugs and dense gelation of polysaccharides, while not adversely affecting biodegradability and biocompatibility.

In addition, the drug may be contained in an amount of 0.1 parts by weight to 100 parts by weight relative to the total temperature sensitive gel.

In another aspect, the present invention provides a method of preparing the temperature sensitive gel for drug delivery according to claim 1, comprising:

(i) radicalizing by adding a redox initiator to the methylcellulose solution;

(ii) adding a pluronic copolymer to perform graft polymerization with the radicals formed; And

(iii) removing unreacted synthetic polymer.

The present invention also relates to the thermosensitive gel; Provided is a composition for sustained release drug delivery, including a hydrophobic or hydrophilic drug.

In particular, the composition is characterized by being administered parenterally, it is preferable that the formulation is typically in the form of an injection.

The drug can be easily injected into the thermosensitive gel according to the present invention through a syringe, and the drug is gradually released after the injection into a hard gel state at the body temperature, thereby increasing the stability of the drug and administering a single-dose drug. In addition to enabling the injection, the drug can be injected into the tissue near the target, thereby increasing the efficiency of drug delivery to the target.

The drug delivery system according to the present invention can be used in the field of development of all drug delivery systems using hydrophobic drugs and hydrophilic drugs, and includes low molecular weight natural polymers and reduces the temperature-sensitive properties even though the content of artificial synthetic polymers is reduced to the minimum required. In addition to maintenance, it is superior in biocompatibility and biodegradability as compared with the drug delivery system consisting of conventional synthetic polymers only.

In particular, since the body is gradually degraded after injection, it is changed into a low-molecular substance that is harmless to the human body, and is discharged out of the body.Therefore, there is no separate surgical removal procedure after the release of the drug for a certain period of time, and no frequent administration is required. It is possible to promote the patient's convenience, and the formed gel is maintained for a long time to release the drug for a desired period of time, and various effects are excellent, and the drug release period lasts for 20 to 40 days. The release is suitable for long-term sustained release formulations, and is expected to be very useful as a drug carrier by enhancing the stability and effect of the drug.

1 is a graph of the gelation temperature of a 5% MC solution as a function of AS concentration.
Figure 2 is a graph of the viscosity and gel formation time measured by a blood flow meter at 25 ℃ and 37 ℃ for the gel of the present invention
Figure 3 is a graph showing the 25-day sustained release pattern of the FITC-BSA model protein from the gel of the present invention.
4 is a graph showing a 40-day sustained release pattern of docetaxel from the gel of the present invention.
Figure 5 is the result of quantification of docetaxel released from the gel by HPLC.
6 is a graph showing the viscosity and gel formation time when the fluorescent material is polymerized to the gel of the present invention
Figure 7 is a photograph of the polymerization of the fluorescent material to the gel of the present invention and injected into the mouse to observe the aspect that they spread over time.
8 is a photo observing the degradation and excretion of each organ by the result of polymerizing the fluorescent material in the gel of the present invention and injected into the mouse.
9 is a graph illustrating the anticancer effect when the gel of the present invention in which docetaxel was enclosed in a cancer-induced animal model was injected.
FIG. 10 is a graph illustrating changes in animal weight when the gel of the present invention in which docetaxel is encapsulated is injected into a cancer-causing animal model.
11 is a graph illustrating the survival rate when the gel of the present invention in which docetaxel is encapsulated in a cancer-causing animal model is injected.
12 is a comparative graph of the anticancer effect (drug delivery effect) according to the use of cyclodextrin.

Definitions of terms used in the present invention are as follows.

"Sol" is the dispersion of colloidal particles in a liquid, the term "gel" has a pore of submicrometer dimensions and typically has an average length greater than 1 micrometer. By an interconnected rigid network of polymer chains, it refers to a semisolid phase that occurs spontaneously when the temperature of the polymer solution rises above the gelling temperature of the block copolymer.

"Gelation temperature" means the temperature at which a biodegradable block copolymer undergoes reverse thermal gelation, below which the block copolymer is soluble in water and above this temperature the block copolymer undergoes a phase transition to increase viscosity or semisolid Form a gel. 'Gelling temperature' and 'inverse thermal gelling temperature' have the same meaning.

"Reverse (negative) thermal gelation" is a phenomenon in which a block copolymer solution spontaneously increases in viscosity or converts into a semisolid gel when the solution temperature is increased above the copolymer gelling temperature. Gels include semisolid gel states and high viscosity states that exist above the gelling temperature. When cooled below the gelling temperature the gel is converted to a low viscosity solution. Cycling between solution and gel is repeated since the sol / gel transition is not related to changes in the chemical composition of the polymer system. All interactions that produce the gel are physical in nature and do not result in breakage or formation of covalent bonds.

"Biodegradable" means that the block copolymer can be chemically degraded in the body to form non-toxic compounds. The rate of degradation is the same or different than the rate of drug release.

By "biocompatible" is meant a substance which interacts with the human body without undesirable subsequent effects.

"Sustained release" refers to the continuous release of a drug or therapeutic agent or any combination thereof over a period of time.

"Controlled release" refers to the control of the rate and / or amount of drug or therapeutic agent delivered in accordance with the drug delivery formulation of the present invention. Controlled release can be continuous or discontinuous and / or linear or nonlinear. This may be achieved by the inclusion of one or more types of polymer compositions, drug loadings, excipients or degradation enhancers, or other modifiers, alone, in combination or in series to provide the desired effect.

"Drug" means an organic or inorganic compound or substance that is bioactive and is used or modified for therapeutic purposes. Proteins, oligonucleotides, DNA and gene therapeutics are broadly included in the drug definition.

"Therapeutic agent" refers to any compound or composition that, when administered to an organism (human or non-human animal), induces the desired pharmacological, immunogenic and / or physiological effects by local and / or systemic action. . Thus the term includes compounds or chemicals that are conventionally considered to be biopharmaceuticals that include drugs, vaccines, and molecules such as proteins, peptides, hormones, nucleic acids, gene constructs, and the like. "Therapeutic agents" include compounds or compositions used in all major therapeutic fields, including but not limited to: anti-infective agents such as antibiotics and antiviral agents; Analgesics and analgesic combinations; Local and general anesthetics; Loss of appetite; Anti-arthritis agents; Anti-asthmatic agents; anticonvulsants; Antidepressants; Antihistamines; Anti-inflammatory agents; Antiemetic agent; Antimigraine drugs; Anti-neoplastic agents; Anti-itch agents; Antipsychotics; fever remedy; Antispasmodics; Cardiovascular preparations (including calcium channel blockers, β-blockers, β-agonists and antiarrhythmic agents); Antihypertensives; chemotherapy; diuretic; Vasodilators; Central nervous system stimulant; Cough and cold preparations; Decongestants; Diagnostic agents; hormone; Osteogenic stimulants and bone resorption inhibitors; Immunosuppressants; Muscle relaxants; Psychostimulants; sedative; Neurostabilizers; Proteins, peptides and fragments thereof (naturally occurring, chemically synthesized or produced by recombination); And nucleic acid molecules (ribonucleotide (RNA) or deoxyribonucleotide (DNA), genetic constructs, expression vectors, plasmids, including polymeric forms of two or more nucleotides, double- and single-stranded molecules and supercoiled or condensed molecules) Antisense molecules, etc.).

"Peptide" "polypeptide" "oligopeptide" and "protein" can be used equally when referring to peptides or protein drugs and are not limited to particular molecular weight, peptide sequence or length, bioactivity or therapeutic field.

"Therapeutic effect" means any improvement in the disease of a subject, human or animal treated according to the method, and means a prophylactic or preventive effect, or a disease that can be detected by physical investigation, laboratory or mechanical methods And obtaining any alleviation in the severity of the signs and symptoms of the disease or illness.

As used herein, unless otherwise defined with respect to a particular disease or condition, the term “treatment” or “treating” means (i) an animal that is susceptible to disease, disease and / or disease but has not yet been diagnosed with disease or To prevent the occurrence of a disease, illness or illness in a human; (ii) inhibit a disease, disorder or condition, ie inhibit its progression; And / or (iii) alleviate a disease, disorder or condition, ie cause disease, disease and / or disease regression.

As used herein, the terms "about", "substantially", and the like, are used at, or in close proximity to, numerical values when manufacturing and material tolerances inherent in the meanings indicated are intended to aid the understanding of the invention. Accurate or absolute figures are used to assist in the prevention of unfair use by unscrupulous infringers.

The present inventors are able to encapsulate hydrophobic drugs using a minimum amount of Pluronic series synthetic polymers, while improving the biocompatibility and biodegradability by using a temperature sensitive gel based on low molecular weight methyl cellulose, thereby making it a hydrophobic or hydrophilic drug. It was found that the sustained release of was possible, and based on this, the present invention was completed.

Hereinafter, the present invention will be described in detail.

In one aspect, the present invention relates to a ubiquitous injectable thermosensitive gel for drug delivery comprising natural polymer, a small amount of synthetic polymer, and salt salt.

More specifically, the present invention relates to a temperature sensitive gel for drug delivery, comprising a salt salt, a temperature-reversible polysaccharide having a molecular weight of 10000 to 20000 Daltons, and a Pluronic synthetic polymer.

In the present specification, the temperature sensitive gel refers to a drug carrier including a polymer having a property of showing a phase change with a change in temperature.

Temperature reversible polysaccharides

The natural polymer used in the drug delivery gel of the present invention has a block copolymer structure composed of a hydrophobic region having a high degree of substitution and a hydrophilic region having a low degree of substitution or no substitution in order to form a temperature-reversible physical gel in an aqueous solution. It is characterized by. The hydrophobic region locally stabilizes the water structure, and upon heating, the water structure is destroyed to enhance hydrophobic interactions, resulting in gelation.

In addition, the natural polymer has a biodegradable property in vivo, and in particular, in order to further increase such biodegradability, the present invention is characterized by using a natural polymer having a small molecular weight.

Representative natural polymers that can be used in the present invention are cellulose.

Cellulose (Cellulose) is composed of the formula (C ₆ H ₁₀ O ₅ ) n, the chemical structure is a number of D-glucose polymerized by β-1,4 bond and are connected in a chain form. Odorless white solid, insoluble in water.

A large number of the cellulose molecules gather to form a fiber, the minimum unit of which is called a micelle, which is 0.05 nm in diameter and 0.6 nm or more in length. It is known that the micelle has a crystal structure through X-ray analysis. The connecting portion of the micelle and the micelle is an amorphous region. This crystalline region and the amorphous region determine the strength, elasticity, dyeability, and hygroscopicity of the fiber. Removing moisture from cellulose makes the amorphous region crystalline and increases its elasticity and strength. When immersed in water or alkali, the liquid penetrates into the amorphous region and swells.

Cellulose is a substance having the largest molecular weight among polysaccharides, and its molecular weight reaches tens of thousands to hundreds of thousands in its natural state. In the present invention, low molecular weight cellulose having a molecular weight of 10000 to 20000 Daltons is preferable. If the molecular weight is less than 10,000 Daltons, there is a problem that the formation of dense gel is difficult, and if it exceeds 20000 Daltons, there is a disadvantage inferior in biodegradability.

That is, the natural polymer used in the present invention is a temperature-reversible polysaccharide having a molecular weight of 10000 to 20000 Daltons, for example, a group consisting of methyl cellulose, hydroxypropylmethylcellulose, ethyl hydroxyethyl cellulose, carrageenan and scelloglucan. Cellulose derivatives selected from, and most preferably methylcellulose.

Methylcellulose (MC) is a hydrophobically modified nonionic cellulose derivative that forms a physically reversible physical gel in aqueous solution. Methylcellulose is an inhomogeneous alternating block copolymer structure consisting of a highly substituted hydrophobic region and a less substituted or unsubstituted hydrophilic region (see Kundu, KK, Polymer. 42 (2001) 2015-2020). . As described above, the hydrophobic region causes the gelation phenomenon by destroying the water structure by heating to enhance hydrophobic interaction. Commercial MCs with a degree of substitution (DS) of 1.4-2.0 undergo sol-gel transitions upon heating at 1.0-2.5% of the MC concentration in water.

In order to apply MC as an in situ-forming drug delivery system that gels at body temperature, it is necessary to modify the reverse (negative) heat-gelling mechanism of MC using additives such as polymers, non-electrolytes or salts, for example. . The gelation temperature of MC may be decreased by increasing the concentration of MC. However, since the viscosity of the solution becomes high and handling becomes difficult, the method of controlling the temperature is more preferable.

Typically the gelling temperature of methylcellulose is at least 55 ° C., which is significantly higher than body temperature, but the gelling temperature can be similarly lowered to body temperature by the addition of any salting-out salt.

A simple way to modify the gelation temperature is to use salting-out salts known to have a significant effect on the phase change of the water soluble polymer (Schott, M .; Royce, AE; Han , SK J Colloid Interface Sci 98 (1984) 196). Anions of salts are known to be much more effective than cations to stabilize nonpolar solutes or hydrophobicity of macromolecules. Hofmeister series (Collins, KD; Washabaugh, MW Q Rev Biophys. 4 (1985) 323) or Lyotropic series (M. Khairy et al., Journal of Polymer Science (2003) 3547-3559) According to the salt concentration of the anion is:

Hopemeister series:

_{^{SO 4 2-> HPO4 2-> F}} -> Cl -> Br -> NO3 -> I -> ClO 4 -> SCN -

Lyotropic series:

^{Al 3+> Ca 2+> Mg 2+} > K + = NH 4+> Na +> Li +, PO 4 3-> SO 4 2-> Cl -> NO 3-

The salt salts usable in the present invention may be any anion by the Hopmeister series or the lyophilic series, most preferably SO ₄ ^2- .

The present inventors confirmed that the gelation temperature is lowered as the concentration of the salt salt increases, and through this, the present inventors were able to prepare a temperature sensitive gel having a desired gelation temperature.

Minimum amount of synthetic polymer

The temperature sensitive gel of the present invention uses the low molecular weight polysaccharide as a gelling base material and contains a minimum amount of synthetic polymer for effective delivery of hydrophilic drugs and encapsulation and delivery of hydrophobic drugs.

In particular, it is preferable to solubilize the hydrophobic drug in order to effectively encapsulate the hydrophobic drug. In the present invention, in order to increase the solubility of hydrophobic drugs, a minimum amount of artificial polymer was added and used to the natural polymer polysaccharide. More specifically, in the present invention, a hydrophobic drug may be encapsulated using a minimum amount of synthetic polymer or a solubilizing agent.

That is, the temperature sensitive gel of the present invention contains a minimum amount of synthetic polymer that can be used only for the loading of hydrophobic drugs as an essential component.

Here, the synthetic polymer may be any synthetic polymer used in the art, most preferably the floronic series. The thermosensitive gel of the present invention is characterized in that it comprises a Pluronic series among synthetic polymers for loading hydrophobic drugs.

Pluronic ™ copolymers are linear triblock copolymers consisting of poly (ethylene oxide) -poly (propylene oxide) -poly (ethylene oxide) as thermosensitive polymers showing sol / gel transitions in aqueous solution .

Pluronic TM F127 used in one embodiment of the present invention is known to exhibit a sol / gel transition phenomenon in an aqueous solution of about 20 parts by weight or more (Macromolecules, 25, 5440-5445, 1992). Ronic synthetic polymers were not used for sol / gel transitions, but only about 5 parts by weight of very small amounts for loading hydrophobic drugs, thereby avoiding adverse effects on biocompatibility and biodegradability.

That is, in the case of hydrophobic drugs, the content ratio of polysaccharide: pluronic is 1: 0.1 to 1: 1. If Pluronic exceeds the range of the ratio, there is a risk of toxicity, so the biocompatibility is lowered and the biodegradability is also reduced by increasing the amount of synthetic polymer. On the other hand, if the ratio does not fall within the range, it is difficult to effectively encapsulate the hydrophobic drug.

In the temperature sensitive gel of the present invention, the hydrophobic drug is encapsulated by Pluronic synthetic polymer and contained in the biodegradable natural polymer polysaccharide matrix. In the present invention, the hydrophobic drug is encapsulated in the polymer micelle formed by the pluronic copolymer and then slowly released from the polymer micelle when injected into the body, so that the hydrophobic drug is maintained at a constant concentration in the body for a long time.

The hydrophobic drugs that can be used may be any drug having a water solubility of 10 mg / ml or less, for example, anticancer drugs, antibacterial drugs, steroids, anti-inflammatory drugs, sex hormones, immunosuppressants, antiviral drugs, anesthetics, antiemetic agents or antihistamines. And the like can be used. Preferably, anticancer agents, such as paclitaxel, docetaxel, doxorubicin, cisplatin, carboplatin, 5-FU, etoposide, camptothecin; Sex hormones such as testosterone, estrogen and estradiol; Steroid derivatives such as triamcinolone acetonide, hydrocortisone, dexamethasone, prednisolone, betamethasone; Cyclosporin; Or prostaglandins and the like can be used.

The content of the hydrophobic drug is 0.1 to 100 parts by weight, preferably 1 to 50 parts by weight, based on the temperature sensitive gel.

On the other hand, the temperature sensitive gel of the present invention may further contain a solubilizer for effective encapsulation of the hydrophobic drug.

Solubilizing agent (solubilizing base) is a substance that can be dissolved in a specific solvent in an aqueous environment, the solubilizing agent preferably used in the present invention includes a carbohydrate-based cyclodextrin.

Cyclodextrins are a series of natural cyclic oligosaccharides consisting of 6, 7, 8 or more D (+) glycopyranose units joined by alpha 1, 4 bonds. Cyclodextrins can be synthesized naturally by, for example, microorganisms. Cyclodextrins can artificially manipulate their properties, for example to modify solubility, complex-forming ability, and specificity.

As used herein, cyclodextrin refers to all forms of natural and artificially modified forms. Suitable cyclodextrins include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin and derivatives thereof, including hydrophobic derivatives, hydrophilic derivatives, charged cyclodextrins, and the like. Preferred cyclodextrins are β-cyclodextrins.

In the present invention, the preferred solubilizer content is about 0 to 15% by weight based on the total temperature sensitive gel. The solubilizer contributes not only to the inclusion of hydrophobic drugs but also to the sustained release effect of the drugs.

On the other hand, the temperature-sensitive gel of the present invention can be effectively used for hydrophilic drug delivery as well as the hydrophobic drug delivery.

In particular, a mixture of a low molecular weight cellulose copolymer having high biodegradability and a peptide / protein drug which is hydrophilic can be prepared as an aqueous copolymer solution below the cellulose gelling temperature to form a drug delivery liquid in which the drug is partially or completely dissolved. As described above, the gelling temperature can be adjusted to a temperature that can be gelled in the body by containing salt salts.

In the present invention, when the delivery drug is a hydrophilic drug, the content ratio of polysaccharide: pluronic is 1: 0.01 to 1: 0.1. In this case, the content of pluronic used for encapsulation of hydrophobic drugs is further reduced, so that the amount of polysaccharide can be formed to form a more dense gel, so as not to adversely affect biocompatibility and biodegradability. The function is to further enhance the sustained release effect.

As such, the drug deliverable in the thermosensitive gel of the present invention is in principle not limited. In other words, the drug may be any hydrophilic drug or any hydrophobic drug. These may be naturally occurring compounds, synthetic organic compounds or inorganic compounds. In addition, simultaneous loading of the hydrophilic or hydrophobic drugs is also possible.

In the present invention, when the hydrophilic drug and the hydrophobic drug are simultaneously loaded as the delivery drug, the content ratio of polysaccharide: pluronic is 1: 0.05 to 1: 0.5. The range is such that the effective encapsulation of hydrophobic drugs and the dense gelation of polysaccharides are possible while not adversely affecting biodegradability and biocompatibility.

When the drug is any hydrophobic drug or any hydrophilic drug, or when loading hydrophobic and hydrophilic drugs at the same time, the content ratio of polysaccharides to pluronics is considered in consideration of gelation, biocompatibility, biodegradability, etc. of polysaccharides. In addition to this, it is also important not to affect the temperature sensitive properties of polysaccharides such as methylcellulose.

For example, according to the gelation temperature of FIG. 1 of the present invention, when the 5% phlotronic is added on the basis of 5% methyl cellulose, the temperature drops by about 2 degrees. It can be seen that it affects.

Thus, as described above, in the case of any hydrophobic drug, or any hydrophilic drug, or simultaneously loading hydrophobic and hydrophilic drugs, the drug in consideration of the gelation, biocompatibility, biodegradability, temperature sensitivity of the polysaccharide, respectively Depending on the nature of the polysaccharide: fluoride content ratio will be slightly different.

Drug substances that may be included in the gel of the present invention include, for example, proteins, polypeptides, carbohydrates, inorganic substances, antibiotics, anti-neoplastics, local anesthetics, antiangiogenic agents, vasoactive agents, anticoagulants, immunomodulators, cytotoxic agents , Antiviral agents, antibodies, neurotransmitters, psychoagonists, oligonucleotides, lipids, cells, tissues, tissues or cell aggregates, and combinations thereof. In addition, cancer chemotherapeutic agents such as cytokines, chemokines, lymphokines and indeed purified nucleic acids, and vaccines such as attenuated influenza viruses. Actually purified hexanes that may be incorporated include genomic nucleic acid sequences, cDNA encoding proteins, expression vectors, antisense molecules and ribozymes that bind to complementary nucleic acid sequences to inhibit translation or transcription. In addition, local anesthetics such as amethokine, articaine, benzocaine, bupivacaine, chloroprocaine, dibucaine, diclonin, ethidocaine, levobupivacaine, lidocaine, mepivacaine, oxetazaine Pramoxin, prilocaine, procaine, proparacaine and ropivacaine; Narcotic analgesics such as alfentanil, alphaprodine, buprenorphine, butorpanol, codeine, codeine phosphate, cyclazosin, dextomorphamide, dezosin, diamorphine, dihydrocodeine, dipyanone, fedodozin , Fentanyl, hydrocodone, hydromorphone, ketobemidone, levorphanol, mephthazinol, methadone, methadyl acetate, morphine, nalbuphine, norpropoxyphene, norcapine, oxycodone, oxymorphone, paregory, Pentazosin, fetidine, phenazosine, pyritramide, propoxyphene, remifentanil, sufentanil, tilidine and tramadol; And non-narcotic analgesics such as salicylate or phenylpropionic acid derivatives. Examples of suitable salicylates include aminosalicylic sodium, val salazide, choline salicylate, mesalazine, olsalazine, para-amino salicylic acid, salicylic acid, salicylic salicylic acid, and sulfasalazine. Examples of suitable phenylpropionic acid derivatives are ibuprofen, phenopropene, flurbiprofen, ketopropene and naproxen and the like.

As such, there is no limitation in the type of drug that can be used, in particular, among the above hydrophilic drugs, since the release rate from the polysaccharide (cellulose) based gel may be somewhat faster than the hydrophobic drug, in the present invention it is recommended to use a hydrophobic drug More preferred.

In another aspect, the present invention relates to a method for producing the temperature sensitive gel.

Thermosensitive gels can be prepared using standard techniques apparent to those skilled in the art. The techniques, amounts, temperatures and times required to prepare the thermosensitive gels for drug delivery of Example 1 of the present invention will be known to those skilled in the art. .

The sensitivity of the gel to various temperatures, such as the stability of the gel to reversible changes from liquid at room temperature to the gel of body temperature, is measured using standard assays or techniques, such as viscometers, to measure viscosity and volume changes at various temperatures. Can be.

In one embodiment, the temperature sensitive gel of the present invention may be prepared by the following method:

(i) radicalization by addition of a redox initiator to the methylcellulose solution dissolved in a suitable solvent;

(ii) adding a pluronic copolymer to perform graft polymerization with the radicals formed; And

(iii) removing unreacted synthetic polymer.

The redox initiator may be any redox initiator used for the radicalization of polysaccharides including cellulose, but ammonium sulfate ((NH ₄ ) ₂ SO ₄ ) was used in one embodiment of the present invention. The methyl cellulose is ring-opened by the redox initiator to form radicals, and a chain polymerization reaction is caused through the coupling with the pluronic copolymer added thereto.

The temperature sensitive gel of the present invention exhibits water solubility or water dispersibility at room temperature according to the concentration of the pluronic copolymer added as described above, the reaction temperature, and the concentration of the initiator, and the temperature sensitivity of the aqueous solution and the low critical solution temperature are changed. .

However, in consideration of the low-critical solution temperature of the temperature sensitive polysaccharide or pluronic copolymer used in the present invention, the reaction is preferably performed at a temperature of 4 to 30 ° C. In particular, when methyl cellulose is used as the polysaccharide, it is preferably performed at a somewhat low temperature. This is because methyl cellulose dissolves in water at a lower temperature than a high temperature.

However, at too low a temperature, the reaction rate is too slow to expect efficiency, and if it is higher than the above range, the pluronic copolymer added to the polysaccharide is present in a gel state and cannot be grafted to the polysaccharide.

Therefore, the case of using methyl cellulose in more detail,

Disperse the methylcellulose well in water and then stir at low temperature for half a day;

The mixture is stored at low temperature;

After dissolving ammonium sulfate in water;

Add any drug and floronics into water and stir at low temperature until they dissolve;

Finally, the methyl cellulose gel and ammonium sulfate pluronic mixture are mixed and used at low temperature.

The thermosensitive gels of the present invention also include one or more drugs or therapeutic agents for short-term therapeutic effects or treatments, wherein the drugs or therapeutic agents dissolve, before or after dissolving the natural and synthetic polymers in solution. It can be added to the polymer used to prepare the gel. Preferably, the drug or therapeutic agent is added prior to dissolution to promote more uniform dispersion or dissolution of the drug or therapeutic agent.

Various techniques for incorporating drugs or therapeutic agents into gels (polymers) are known and include, but are not limited to, spray drying, solvent evaporation, phase separation, deep freezing, and solvent extraction.

A drug or therapeutic agent is included in the gel in an amount of about 0.1 to about 100 parts by weight, preferably about 1 to about 50 parts by weight, and more preferably about 10 to about 30 parts by weight. However, a drug or therapeutic agent may be included in 0.01 to 95 parts by weight of the gel. The amount or concentration of drug or therapeutic agent included in the gel will depend on the rate of absorption, deactivation and release of the drug or therapeutic agent as well as the rate of delivery of the polymer in the gel.

The temperature sensitive gel for drug delivery according to the present invention, prepared by the above method, is liquid at room temperature. Immediately after injection into the subject, the gel becomes due to body temperature. Drugs or therapeutic agents contained within the temperature sensitive gel will diffuse into the extracellular matrix of the subject and will be released by controlled means to the target site.

Sustained release drug delivery compositions and systems

In another aspect, the present invention includes a pharmaceutical composition for controlled drug release comprising a plurality of drugs or therapeutic agents in a biodegradable and biocompatible gel, wherein the composition is introduced into a patient in need thereof. Including methods of treating diseases, disorders or conditions, and methods of making the systems of the present invention.

That is, the present invention relates to a pharmaceutical composition for sustained-release drug release containing a thermosensitive gel containing a salty salt, a temperature-reversible polysaccharide having a molecular weight of 10000 to 20000 Daltons, and a pluronic synthetic polymer and a desired drug. .

The temperature sensitive gels of the present invention can be formulated to be bioabsorbable, biodegradable, biocompatible. Bioabsorbable means that the polymer may disappear in the initial application in the body, without degradation or degradation of the dispersed polymer molecules. Biodegradability means that the polymer can be broken down or degraded in the body by hydrolysis or enzymatic degradation. Biocompatibility means that all of the ingredients are nontoxic in the body.

Therapeutic drug delivery systems of the present invention provide for the delivery of a drug in the drug system by injection or other method suitable for a person or other mammal having a therapeutically effective disease state or condition (e.g., implantation, body cavity, or Incorporation, coating the tissue surface of the body or coating the surface of the implantable device), but in particular, the composition is preferably delivered parenterally. By parenteral means intramuscular, intraperitoneal, intraperitoneal, subcutaneous, intravenous and intraarterial.

Therefore, the compositions of the present invention can be representatively formulated in injection formulations.

In order to apply the temperature-sensitive gel as a drug carrier for injection or functional support for tissue regeneration, the gel should have low viscosity, fast gel formation, and low molecular weight to be easily discharged to the outside of the body. By introducing the Pluronic polymer at the above-mentioned ratio, it was possible to maintain low viscosity and low molecular weight, which are one of the requirements of the biocompatibility and temperature sensitive gel.

Injectable compositions of the invention may be injected or inserted into the body of a human or other mammal by any suitable method, preferably by injection through a hypodermic needle.

For example, it can be administered by injection or in any other way, intraarterial, intravenous, genitourinary, subcutaneous, intramuscular, subcutaneous, intracranial, intracardiac, intrapleural, or other body cavity or possible space. Or through a catheter or syringe, for example, during arthroscopy, intraarticularly, into the genitourinary tract, into the vasculature, into the palate or into the pleura, or into any body cavity or possible space in the body, surgery, surgery, diagnosis or Can be introduced during interventional procedures. The hydrogel is administered to a defined area or tissue to increase the local concentration of the drug to form a delayed release depot. In other applications, it may be applied topically to open surgery or trauma wounds, burns, or skin or other tissue surfaces.

In one embodiment of the present invention, the preparation of an injection formulation is as follows.

The biocompatible and temperature sensitive methyl cellulose and ammonium sulfate were dissolved in PAL by adding PBS, and the drug was pluronic at 5 × 10 ^-5 to 50 parts by weight, more preferably 0.05 to 10 parts by weight, relative to 100 parts by weight. PBS was added to the vial together with a copolymer to dissolve the sol to form a sol, followed by uniform dispersion at 4 ° C. for 1 day, followed by vigorous stirring with the prepared methylcellulose and ammonium sulfate to prepare a physically mixed injection formulation.

On the other hand, the present invention is characterized in that the drug is a sustained release composition to be slowly released in the body when injected into a specific site in the body.

The thermosensitive gel of the present invention is suitable for use as a slow release of the drug and as a controlled release matrix. When the matrix is coupled with one or more therapeutic agents contained homogeneously therein, a biodegradable sustained release drug delivery system is provided. As used herein, the term "sustained release" (ie, prolonged release or controlled release) is introduced into a human or other mammal, or on an open wound, burn or tissue surface or in a body cavity or latent body. A drug delivery system or composition, introduced in space, that continuously releases one or more therapeutic streams over a predetermined time at a therapeutic level sufficient to achieve the desired therapeutic effect over a predetermined time.

Since the composition of the present invention uses cellulose, which is a biocompatible polymer that is decomposed into a substance harmless to the human body after a certain period of time, is released into the body, the release rate of the drug can be controlled according to the content of the constituents. Therefore, when the composition according to the present invention is injected into a specific site in the body by using a general syringe or a catheter, the drug is released slowly, so that the drug is maintained at a constant concentration for a long time in the circulating blood, and thus the drug expression is excellent.

In addition, according to the sustained release drug delivery system of the present invention, the drug or therapeutic agent may be released in a controlled manner to the target site of the subject.

In one embodiment, a thermosensitive gel is used to provide site-specific release of a drug or therapeutic agent to a subject. In another embodiment, the thermosensitive gel includes one or more drugs or therapeutic agents that can be administered to the subject, such that the drugs or therapeutic agents are released by diffusion from the gel and / or degradation of the gel.

At this time, the dosage value of the composition will vary depending on the type and severity of the disease, disorder or condition being treated. For any particular subject, it should be further understood that the specific dosage regimen should be adjusted over time in accordance with the needs of the individual and the professional judgment of the person administering or directing the composition. In vivo administration can be based on in vitro release studies in cell culture or on in vivo animal models.

As such, the methods and compositions of the present invention provide for optimal delivery of the drug or therapeutic agent because it releases the drug or therapeutic agent in a controlled manner. As a result of controlled delivery, the drug is delivered for the desired period of time. Slower and more constant rates of delivery may, in turn, result in a decrease in the frequency with which the drug or therapeutic agent should be administered to the animal.

The rate of release of the drug or therapeutic agent depends on many factors, in particular on the rate of degradation of the biodegradable polymers that make up the gel. It also depends on the particle size of the drug or therapeutic agent. Thus, by adjusting the factors discussed above, decomposition, diffusion and controlled release can vary in a wide variety of ranges. For example, the release can be designed to occur over time, days, months.

While various aspects of the compositions have been described in detail, it will be apparent to those skilled in the art that modifications, substitutions and additions can be made without departing from the spirit and scope of the invention. All patents, patent applications, articles and publications mentioned herein above and below are hereby incorporated by reference.

[Example]

Hereinafter, the present invention will be described in detail with reference to the following examples and accompanying drawings. The following examples are only intended to describe the present invention in more detail, and the protection scope of the present invention is not limited to the examples described in the following examples. In addition, not only the following examples but also matters that can be easily inferred by those skilled in the art are obviously included in the protection scope of the present invention.

Example 1 Preparation of Temperature Sensitive Gel

Methylcellulose (MC, Mn = 14,000, viscosity = 15 cps), bovine serum albumin (FITC-BSA) conjugated with fluorescein isothiocyanate, and ammonium sulfate (AS) were added to Sigma-Aldrich (St. Louis, MO, USA) and docetaxel from Fluka (Buchs, Switzerland) and Pluronic from BASF Corp. (Parsippanny, NJ, USA).

1-1 Preparation of Methyl Cellulose Aqueous Solution

0.3-15 parts by weight of MC solution was prepared by dispersing MC powder in required phosphate buffered saline (PBS) preheated to 90 ° C. and stirring until completely wet. The mixture was stirred slowly in an ice cold bath for 1 day to produce a colorless clear solution. The solution was shaken and frozen.

5 parts by weight of MC aqueous solution by tube inverting method while adding salt salt ammonia sulfate (SO ₄ ^2- ) to MC solution and raising the temperature by 0.5 ° C. at 5 minute intervals over a temperature range of 10-40 ° C. Significant gelatin gelation temperature of was measured.

The results are shown in FIG. When the methyl cellulose polymer of various concentrations were used as the temperature sensitive gel, it was confirmed that each had a different gelling temperature. Through this, it can be seen that it is possible to make a gel having a desired gelling temperature using salt salts.

1-2 Pluronic  Polymer addition

Significant gelatin gelation temperature was measured in the same manner as 1-1 by adding 5% Floronic F-127 in a thermosensitive polysaccharide gel having various gelation temperatures prepared above.

As a result, as shown in Figure 1, the addition of synthetic polymer pluronic gelling temperature slightly decreased, but the intrinsic gelation property was confirmed that there was no change.

In addition, the viscosity change with temperature was measured in a gel prepared using 5% Floronic F-127, 5% methylcellulose, and 3% ammonium sulfate. Using pulsatile blood flow meters (Bohlin, Malvern, UK), gel formation and viscosity measurements at various temperatures were performed by cone and plate geometry methods within the temperature range of 0-60 ° C. Samples (500 μl) were placed between two 20 mm parallel plates separated at 500 μm intervals.

As a result, as shown in FIG. 2, although the viscosity was low at 25 degreeC, it confirmed that the viscosity increased at 37 degreeC.

Through this, it was confirmed that the prepared temperature-sensitive gel is in a liquid state at a low temperature, but when the temperature is increased above a certain level, the gel is changed to a solid state while the viscosity is increased accordingly. In addition, it was also confirmed that the viscosity was reversibly changed in accordance with the change in temperature through the continuous change in the viscosity in accordance with the change in temperature.

Example  2: hydrophilic drug loading and release efficacy

Drug release experiments were carried out for the hydrophilic drug Fitc-BSA using the gel prepared above. That is, FITC-BSA was added to the aqueous gel solution prepared above, and a sample vial was placed in a 37 ° C. water bath to form a gel, and then covered with a pre-warmed PBS of pH 7.4 and vibrated at 100 rpm. . At predetermined time intervals, the medium was released and drained and replaced with fresh buffer. Protein concentration was measured with a UV spectrophotometer.

As a result, as shown in Figure 3, in the drug release experiment using the hydrophilic model drug Fitc-BSA it was confirmed that the drug is continuously released for 20 days.

Example 3 Hydrophobic Drug Loading and Release Efficacy

In a similar manner to Example 2, the drug release experiment was conducted on the hydrophobic drug docetaxel using the gel prepared in Example 1.

As a result, as shown in Figure 4, in the drug release experiment using the hydrophobic drug docetaxel was confirmed that the drug is continuously released over 30 days. In addition, it was confirmed that when about 40 days passed 100% drug was released.

In addition, it was quantified by HPLC to see if there is no change in the properties or functions of docetaxel released from the gel.

As a result, as shown in Figure 5, the quantitative determination of docetaxel by HPLC confirmed that it is released in the gel without change in the docetaxel structure, which suggests that docetaxel encapsulated in the gel of the present invention maintains its own function .

Experimental Example  One: Gel  Biodegradable and Discharge  Confirm

Fluorescent materials were polymerized on the gel to confirm the biodegradability and releaseability of the gel.

After polymerizing 5% Cy5.5 to a gel prepared using 5% Floronic F-127, 5% methylcellulose, and 3% ammonium sulfate, the viscosity change with temperature was measured in the same manner as in Example 1-2. Measured.

As a result, as can be seen in Figure 6, even after the polymerization of the fluorescent material to the gel it was confirmed that the inherent gelation properties of the gel does not change.

1-1 Gel  Biodegradable

Ketamine hydrochloride (90 mg / kg) and xylazine hydrochloride (5mh / kg) were intramuscularly administered (90 mg / kg) to anesthetize Balb / C (20-25 g, SLC, Tokyo, Japan). All handling and care of these laboratory animals is published in the National Institute of Health, "The Guide for the Care and Use of Laboratory Animals" (NIH Publication 85-23, 1985). Revised).

Gels polymerized with the fluorescent material were injected subcutaneously into the back of mice with a sterile hypodermic syringe of 26 G X 1/2 gauge and recovered after injection.

As a result, as can be seen in Figure 7, it was confirmed that the fluorescent material gradually spread from the site where the gel was injected [after injection, 0 day (A), 1 day (B), 2 days (C), 1 week (D), 2 weeks (E) and 3 weeks (F)] This result suggests that the gel is slowly withdrawn in vivo, thus suggesting that the gel of the present invention is biodegradable.

1-2 Gel Discharge

Fluorescence was measured by extracting the liver, lung, heart, spleen and kidney tissues of the mouse.

As a result of measuring the fluorescence of each organ, it was confirmed that the injected gel was decomposed and discharged by the liver and kidney as shown in FIG. C), 1 week (D), 2 weeks (E) and 3 weeks (F)]. This also shows that the gel is biodegradable and released through the kidneys. .

Example 4: Using an Animal Model Anticancer drugs  Anticancer effect of delivery

4-1 Anticancer Effect

Anti-cancer efficacy test by transplanting B16-F10 Melanoma cancer cells (1.5 X 106 cells) between 12 cells in the right flank of C57BL / 6 black mouse (5 weeks old, 20-25 g) used in the above experiment. Animals were prepared for use.

When the volume of the transplanted cancer tissue reached 100 mm 3, the gel composition prepared in Example 3 was sterilized using UV under sterile conditions and then directly administered to the cancer tissue using a 26 gauge syringe needle (intratumoral, it ).

The composition of the present invention was administered once so that 5, 10, 30 mg / kg docetaxel is encapsulated in 200ul gel (day 0), and the control group was administered once to cancer tissue by dispersing 5 mg / kg docetaxel in PBS. After administration, the length of the long axis and short axis of cancer tissue were measured at 2-3 days intervals .

As a result, as shown in Figure 9, when the docetaxel-encapsulated gel is injected into the animal model causing cancer was confirmed that the growth of cancer is significantly reduced. In particular, it can be seen that the use of the drug delivery gel of the present invention can maximize the anticancer effect of docetaxel as compared to the group not using the gel of the present invention as a control.

4-2 Toxicity Test and Survival Rate

In addition, when using the gel containing the anticancer drug docetaxel, in order to determine whether the toxicity in the body may be a problem, the weight change was observed, and further confirmed the survival rate.

As a result, as can be seen in Figure 10 weight loss in all groups did not appear, which means that the gel of the present invention does not have toxicity. In addition, the results of observing the survival rate also showed a high survival rate when the docetaxel is injected into the gel as shown in FIG.

Example  5: Cyclodextrin  Added efficacy

The effect of additional solubilizers on loading of hydrophobic drugs was attempted.

To this end, tocopherol succinate (TOS) was used as a hydrophobic drug and cyclodextrin was used as its solubilizing agent. Only TOS dissolved in organic solvent (DMSO) was contained in the gel and treated with cancer cell SCC-7 (Squamous Cell Carcinoma) (control), and on the other hand, TOS loaded in cyclodextrin was contained in the gel and treated with cancer cells. In each case, the viability of the cancer cells was observed.

As a result, as shown in Figure 12, it was confirmed that the anti-cancer effect significantly increased at low concentration when using TOS cyclodextrin together. This indicates that when the solubilizing agent cyclodextrin is encapsulated in the gel of the present invention, even a small amount of hydrophobic drug can obtain more effective anticancer effect.

Claims (14)

A temperature-sensitive gel for drug delivery, comprising a salt salt, a temperature reversible polysaccharide having a molecular weight of 10000 to 20000 Daltons, and a Pluronic synthetic polymer.
The gel of claim 1, wherein the drug is one or more drugs selected from the group consisting of hydrophilic drugs and hydrophobic drugs.
The gel according to claim 2, wherein when the drug is a hydrophobic drug, the content ratio of polysaccharide: pluronic acid is 1: 0.1 to 1: 1.
The gel according to claim 2, wherein when the drug is a hydrophilic drug, the content ratio of polysaccharide: pluronic is 1: 0.01 to 1: 0.1.
According to claim 1, wherein the drug is a hydrophilic drug and a hydrophobic drug, the gel is characterized in that the content ratio of polysaccharides: pluronic 1: 0.05 ~ 1: 0.5.
The gel of claim 1, wherein the temperature sensitive gel further comprises a solubilizer.
The gel of claim 6, wherein the solubilizer is a carbohydrate-based cyclodextrin.
The gel according to any one of claims 1 to 4, wherein the thermoreversible polysaccharide is methylcellulose.
The method of claim 1, wherein the salting out salt is Hope Meister series _{^{(SO 4 2-, HPO 4 2-}} , F -, Cl -, Br -, NO 3 -, I -, ClO 4 -, SCN -) or lyophilic series ^{(Al 3+, Ca 2+, Mg} 2+, K +, NH 4 +, Na +, Li +, PO 4 3-, SO 4 2-, Cl -, No 3 -) 1 , selected from the group consisting of A gel characterized by being at least a species.
10. The gel of claim 9, wherein said salt salt is SO ₄ ^2- .
The temperature sensitive gel of claim 1; A sustained release drug delivery composition comprising a hydrophobic and / or hydrophilic drug.
The composition of claim 11, wherein the composition is administered parenterally.
12. The composition of claim 11, wherein said composition is formulated in an injectable form.
A method of preparing a temperature sensitive gel for drug delivery according to claim 1 comprising:
(i) radicalizing by adding a redox initiator to the methylcellulose solution;
(ii) adding a pluronic copolymer to perform graft polymerization with the radicals formed; And
(iii) removing unreacted synthetic polymer.

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