JPH09263547A - Accelerating substance for percutaneous absorption and production of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an accelerating substance for a percutaneous absorption, capable of avoiding a skin irritation or toxicity while enhancing the medicine absorption capability of a skin by utilizing a high molecular organic compound. SOLUTION: This accelerating substance for a percutaneous absorption consists of plural cyclic compounds of α,β,γ-cyclodextrins, a linear chain like high molecular compound piercing through the cavity of the cyclic compounds (e.g. polyethylene glycol) and degradable parts in a living body bonded to both the ends of the linear chain like high molecular compound, and also an aggregate of the polymer degradable in the living body having an ultra molecular structure obtained by hydroxypropylation of the above α,β,γ-cyclodextrins. The degradable part in the living body is obtained by adding pseudopolyrotaxane to Z-L-Phe-succinimide to obtain Z-L-Phe-polyrotaxane, then hydroxypropylating and deprotecting the Z-group as necessary. An aqueous solution of indomethacin is excellent in permeability.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel substance for promoting percutaneous absorption of a drug.

[0002]

2. Description of the Related Art A transdermal absorption system (TTS), which efficiently absorbs a drug through the skin and exerts a systemic or local pharmacological effect, must improve the skin absorbability of the drug by using a transdermal absorption enhancer. is there. Generally, the outermost layer of the skin is covered with keratinocytes, which are called stratum corneum and have been differentiated and accumulated and then play a role of protection against invasion of foreign substances not only from drugs but also from the outside world such as bacteria. Therefore, in order to absorb the drug from the skin, it is necessary to strongly interact with proteins such as intercorneocyte lipids and intracellular keratin existing in the stratum corneum to disturb or destroy these ordered structures. A substance having such an action is generally called a percutaneous absorption enhancer, and many low-molecular-weight polar organic compounds have been studied so far, and it has an action to dramatically enhance the percutaneous absorption enhancer of a drug. It has been reported. Initially, polar solvents such as dimethyl sulfoxide having an action of extracting keratinocyte lipids or destroying the lipid bimolecular structure, natural moisturizing factors such as pyrrolidonecarboxylic acid, and various surfactants such as higher fatty acids were investigated. Subsequently, it was reported that 1-dodecylazacycloheptan-2-one, known under the trade name of Azone, has a higher absorption promoting effect by denaturing not only intracellular lipids but also proteins contained in cells such as intracellular keratin. ing. "The effect of various transdermal absorption enhancers on the structure change of water in the stratum corneum of the skin and the indomethacin permeability" by the present inventors and others (Drug Delivery System).
Vol. 7 No. (Issued in 1992), the relationship between the stratum corneum bound water content and% extraction and the P value was 0.20.
It has been announced that the P value increases when the amount is g / g or more and less than 0.25 g / g, and a cost absorption promoting substance that makes the stratum corneum bound water amount 0.20 g / g or more and less than 0.25 g / g is desired. It is rare.

[0003]

However, these percutaneous absorption enhancers are all low molecular weight organic compounds,
It was found that it not only interacts with keratinocytes but also penetrates into tissues under the skin and strongly acts on cells constituting these tissues, and causes cytotoxicity and subcutaneous inflammation after long-term use. That is, these percutaneous absorption-promoting substances not only affect the ordered structure of the stratum corneum but also permeate through the stratum corneum and penetrate into the sub-corneal body, specifically, the dermis and subcutaneous tissues. As a result, it has a problem that it shows skin irritation and skin toxicity. For this reason, the transdermal absorption enhancers that have been conventionally used have been taken a new approach in search of a safe transdermal absorption enhancer.
One of them is a low molecular weight compound such as limonene contained in citrus fruits which is safe to be absorbed into the subcutaneous tissue, and the other is a high molecular compound which is not absorbed into the subcutaneous tissue even when acting on keratinocytes. However, any of the compounds is characterized by improving the distribution of the drug to the stratum corneum, and many drugs have not been able to improve the drug diffusibility sufficient to improve the skin absorbability. Therefore, the present invention has been made in view of the above-mentioned drawbacks of the prior art, and a percutaneous absorption enhancer capable of avoiding skin irritation and toxicity while improving the drug absorption of the skin by using a high molecular weight organic compound. I found it.

[0004]

That is, the present invention is based on α,
β or γ-cyclodextrin a plurality of cyclic compounds, a linear polymer compound penetrating the cavity of the cyclic compound,
A biodegradable polymer assembly comprising a biodegradable site bonded to both ends of this linear polymer compound and having a supramolecular structure obtained by hydroxypropylating the above α, β or γ-cyclodextrin. This object is achieved by a percutaneous absorption enhancer consisting of. The invention of claim 3 relates to a method for producing the percutaneous absorption enhancer, which comprises: a) synthesizing ZL-Phe-succinimide by reacting carbobenzoxy-L-phenylalanine with N-hydroxysuccinimide (N-HOSu). And b) adding α- (3-aminopropyl) -ω- (3-aminopropyl) poly (oxyethylene) to the cyclodextrin aqueous solution to prepare a pseudopolyrotaxane, and c) the above a) The step of adding the pseudo-polyrotaxane obtained in the step b) to the solution of the ZL-Phe-succinimide obtained in the step to synthesize ZL-Phe-polyrotaxane, and the step d) obtained in the step c). Hydroxypropylating ZL-Phe-polyrotaxane. The relationship between α, β or γ-cyclodextrin and polymers penetrating the voids of these cyclodextrins has already been investigated by Dr. Harada of Osaka University (Surface discourse / colloid congress 1994 Vol.32 No.2). It has been pointed out that the following polymers are penetrable. 1) In the case of α-cyclodextrin Polyethylene glycol 2) In the case of β-cyclodextrin Polyethylene glycol, polypropylene glycol,
Polyisobutylene 3) In the case of γ-cyclodextrin Polyethylene glycol, polypropylene glycol,
Polyisobutylene, polymethyl vinyl ether, and bulky groups at the end, such as 2,4-dinitrophenyl group, 3,6-dinitrobenzoyl group can not penetrate if bound, so a methyl group, methoxy group, The one to which a small functional group such as an amine group is bonded is used. The average molecular weight of polyethylene glycol, polypropylene glycol, polyisobutylene or a block copolymer thereof is 200 to 5000, preferably 400 to 20.
00.

The biodegradable site to be bonded to both ends of a linear polymer compound has 1 to 5 repeating units, and its constituent amino acids are alanine, valine, leucine,
Isoleucine, methionine, proline, phenylalanine, tryptophan, aspartic acid, glutamic acid,
An oligopeptide chain consisting of one or more of glycine, serine, threonine, tyrosine, cysteine, lysine, arginine, and histidine, or a repeating unit of 1 to 5 and dextran, hyaluronic acid, chitin, chitosan, alginic acid as constituent polysaccharides. It is preferable to use a site having an oligosaccharide chain consisting of chondroitin sulfate, starch, and pullulan.

[0006]

In the supramolecular percutaneous absorption enhancer according to the present invention, cyclodextrin penetrating a linear polymer such as polyethylene glycol, polypropylene glycol or a block copolymer thereof has a strong hydrogen bonding property to form a stratum corneum component. Depending on the molecular form of the supramolecular percutaneous absorption enhancer, it interacts with each other to promote drug diffusion, or does not penetrate subcutaneously, or after penetration into the skin, oligopeptide chains and oligosaccharide chains that are subcutaneous degradable sites Alternatively, when the ester group or the like is decomposed, cyclodextrin is detached from polyethylene glycol, polypropylene glycol, or a block copolymer thereof at one time to ensure safety for subcutaneous tissue. That is, depending on the morphology of the supramolecule, it is not absorbed into the tissue below the stratum corneum, or even if absorbed, it is irritating to the subcutaneous tissue due to the decomposition of the subcutaneously degradable site such as oligopeptide chains, oligo chains or astel groups. Toxicity can be avoided.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to Examples. Example-1 A transdermal absorption enhancer having a supramolecular structure used in the present invention was prepared through the steps A to D shown below. A) Synthesis of ZL-Phe-succinimide Carbobenzoxy-L-phenylalanine ((ZL-Phe) (14.5 g) and N-hydroxysuccinimide (N-HOSu) (5.58 g) were dissolved in dioxane (140 ml). This solution was cooled in a refrigerator (12 ° C.), DDC (9.99 g) was added with stirring, and the solution became cloudy. When the solution was stirred in a freezer (4 ° C.) overnight, it solidified. Dissolved and the by-product N-N'-dicyclohexylurea was removed by filtration.
The filtrate was concentrated under reduced pressure with an evaporator and then added dropwise into ether to give a white precipitate. The precipitate was collected by centrifugal filtration and dissolved in dichloromethane. Petroleum ether (poor solvent) was added dropwise while gently shaking this solution, and when a slight white turbidity was observed, the solution was left standing overnight in a refrigerator for recrystallization. The generated crystals were collected by filtration and dried under reduced pressure (yield 48%). The purity of the product was confirmed by melting point measurement (138 ° C.) by differential scanning calorimetry.

[0008]

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B) Pseudopolyrotaxane (α-CD-PEG4000-B
Preparation of A) Saturated α-cyclodextrin (CD) aqueous solution (1.45 g / 10 ml, 1.
49 × 10 ² mM) to α- (3-aminopropyl) -ω- (3-aminopropyl) poly (oxyethylene) (PEG4000-BA, Mn = 412
0) (0.13 g, 3.2 × 10 ⁻⁴ mmol) was added and the mixture was stirred for 3 hours, whereupon the solution became cloudy. The solution was sonicated for 30 minutes and then left standing overnight to obtain a white precipitate. The precipitate was collected by centrifugal filtration, washed twice with water, and dried under reduced pressure for 6 hours to obtain a white powder (yield 85%). From H-NMR, from the integral ratio of PEG: -OCH ₂ CH ₂ (δ = 3.5) and α-CD: C (1) H (δ = 4.8), the PEG4000-BA chain When the average number of molecules was determined, it was 35-40.

C) ZL-Phe-polyrotaxane (α-CD-PEG4
ZL-Phe-Su (5.4 g) was dissolved in DMSO (7 ml). Pseudopolyrotaxane (α-CD-PEG4000-BA) was added and stirred under N ₂ atmosphere for 3 days (DMSO (5 ml) was added 3 times during this period). The reaction solution was dropped into ether and the resulting precipitate was collected by centrifugal filtration. Wash the recovered material with acetone and water
ZL-Phe-polyrotaxane was obtained (2.06 g, 42% yield). HN
From MR, introduction was confirmed by the presence of Z group: CH ₂ O- (δ = 5.0) and Phe: -CH ₂ CH- (δ = 4.8).

[0011]

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D) Hydroxypropylation of ZL-Phe-polyrotaxane ZL-Phe-polyrotaxane (α-CD penetration number 35-40) (0.2 g)
Was dissolved in 15 ml of 1N NaOH. 2.6 ml of propylene oxide (PPO) was added dropwise to this solution, and the mixture was stirred for 24 hours and then neutralized with hydrochloric acid. Dialysis membrane (MW
Dialysis was performed for 5 hours (3 liters of distilled water 3 times) for 5 hours or less. This solution was concentrated under reduced pressure with an evaporator and dropped into acetone to generate a precipitate. This was collected by centrifugal filtration and dried under reduced pressure overnight to obtain HP ZL-Phe-polyrotaxane. From H-NMR, hydroxypropyl group: CH _2-
The introduction was confirmed by the presence of (δ = 2.1) and Phe: -CH ₃ (δ = 1.0).

[0013]

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E) Deprotection of Z group Deprotection of Z group was carried out by a catalytic reduction method. HP ZL-Phe-
Polyrotaxane (0.45 g) was dissolved in 11 ml of distilled water. Palladium carbon (0.46 g) was added to this aqueous solution, and hydrogen was added to
Flowed for 0 minutes. After the atmosphere was sufficiently replaced with hydrogen, stirring was started. After stirring in hydrogen for 3 days, centrifugal filtration (3400 rpm for 10 minutes) and microfilter (Cosmonice filter, for aqueous solution) to remove palladium carbon
It was filtered through a membrane pore (0.45 μl). The filtrate was concentrated under reduced pressure with an evaporator and then added dropwise to 200 ml of acetone, and a white precipitate was produced. This precipitate was collected by centrifugal filtration and dried under reduced pressure overnight (0.25 g).

(Test 1) ZL-Phe-obtained in the above example
A skin permeation test of indomethacin was carried out using a transdermal absorption enhancer of polyrotaxane. Preparation of drug solution 12.1% aqueous solution of ZL-Phe-polyrotaxane (present invention), purified water (Comparative Example 1) as comparative example, PBS (potassium hydrogen phosphate) (pH: 7.4, 0.14M) (Comparative example 2) We prepared and compared the drug permeation performance of hydroxypropylated polyrotaxane by the following method.

Skin permeation test 1) Pretreatment of skin Using 7-week-old male hairless rats (body weight 150 g), 25
% Urethane (5ml / 5kg, ip) Under hair anesthesia, the abdominal skin was removed and immediately sandwiched in a 2-chamber diffusion cell (effective diffusion area 0.79cm ² , volume 2.5ml) circulated with hot water at 37 ° C. 2.0 ml of each of the drug solutions was placed on the keratin side (donor side), and 2.5 ml of PBS (pH: 7.4, 0.14M) was placed on the dermis side (receiver side), and the mixture was stirred with a magnetic stirrer for 18 hours.
After that, both cells were washed twice with PBS. 2) Permeation test After washing both cells, put indomethacin suspension (approx. Twice the saturated solubility in PBS) on the donor side and 2.5 ml of PBS on the receiver side, and stir with a magnetic stirrer. A permeation test was conducted at 37 ° C for 8 hours. For sampling, 500 μl each was withdrawn at 2, 4, 6 and 8 hours after the start of the experiment, and the same amount of PBS was added to keep the liquid volume on the receiver side constant. For comparison, Comparative Example 3 was prepared without pretreatment with a drug solution.
And 3) Method for measuring the concentration of indomethacin in the sample To 500 μl of the sample solution, add 500 μl of the internal standard solution (mefenamic acid in methanol, 10 μg / ml), mix, and then centrifuge.
(10000 r.pm, room temperature, 5 min.), And the supernatant (20 μl) is HPL.
Measured by C. The HPLC conditions are as shown in Table 1 below.

[0017]

[Table 1]

(Permeation test results) The permeation-promoting effect of polyrotaxane was examined in the permeation experiment of indomethacin using the isolated skin of hairless rats, and in the purified water provided as a comparative example, Flux: 1.90 μg / cm ² / hr And 8 hours accumulated permeation: 9.10 μg / cm ² , whereas polyrotaxane pretreated had Flux: 3.46 μg / cm ² / hr, 8 hours accumulated permeation: 19.27 μg / cm ² And about doubled. Also L
The ag time was also shortened from 3.5 hours in the H ₂ O group to 2.5 hours. Further, in the case of PBS and the case where no pretreatment was performed, the results are shown in Table 2 and FIG. 1 below.

[0019]

[Table 2]

(Test 2) Hydroxypropylated ZL-Phe-
In order to investigate the effect of polyrotaxane on the stratum corneum, HP (L-Phe-α-CD / PEG4000) consisting of the following Table 3 and other organic solvents (purified water, ethanol, DMSO,
Azone and hydroxypropylated cyclodextrin and L-Phe • PE prepared by the following F) and G)
G4000), and to each of them, the rat stratum corneum 1
After soaking for 8 hours, it was washed with water and dried. 60 layers of this stratum corneum
% Of water, DSC measurement was performed, and the amount of bound water was determined from the heat of fusion of the obtained water. Furthermore, the change of stratum corneum lipids by the solution treatment was examined using high-sensitivity DSC. The results are shown in Table 3 below.

F) Hydroxypropylation of α-CD α-CD (10 g) was dissolved in 100 ml of 1N NaOH. Propylene oxide (PPO) (8.6 ml) was added dropwise to this solution, and the mixture was stirred for 24 hours and then neutralized with hydrochloric acid. In order to remove the generated salt, dialysis was performed for 5 hours (3 liters of distilled water 3 times) with a dialysis membrane (permeation of MW = 500 or less). This solution was concentrated under reduced pressure with an evaporator and dropped into acetone to generate a precipitate. This was collected by centrifugal filtration and dried under reduced pressure overnight to obtain HP α-CD.

G) Synthesis of L-Phe-PEG4000 ZL-Phe-Su (1.7 g: 4.8 × 10 ^-4 mmol) was dissolved in DMSO (2 ml). 0.5 g (1.2 × 10 ^-4 m) of PEG4000-BA (Mn = 4120) was added to this solution.
mol) and stirred under N ₂ atmosphere for 3 days.
DMSO (2 ml) was added 3 times). The reaction solution was dropped into ether and the resulting precipitate was collected by centrifugal filtration. The collected material was washed twice with ether to obtain ZL-Phe-polyrotaxane
(0.3g).

[0023]

[Table 3]

(Discussion) As Table 3 shows that DMSO is extracted with an increase in bound water, it is considered that hydrophobic lipid is extracted. Ethanol, AZONE, and hydroxypropylated cyclodextrin were extracted with a decrease in bound water, and polar lipid extraction was considered. It was also suggested that hydroxypropylated cyclodextrin was extracted in a concentration-dependent manner. On the other hand, a mixture of hydroxypropylated cyclodextrin and L-Phe-PEG4000 and hydroxypropylated ZL-Phe-polyrotaxane both showed about 10% extraction, but the decrease in bound water was due to hydroxypropylated ZL-Phe- Found in polyrotaxane. Moreover, this effect of reducing bound water was higher in hydroxypropylated ZL-Phe-polyrotaxane than in 41% aqueous solution of hydroxypropylated cyclodextrin. This is probably because the formation of the polyrotaxane structure increased the local concentration of hydroxypropylated cyclodextrin. In addition, from high sensitivity DSC measurement to AZONE and DMSO
Extraction of lipid was observed in the treatment, but the presence of lipid was observed in hydroxypropylated ZL-Phe-polyrotaxane. From these results, it is expected that hydroxypropylated ZL-Phe-polyrotaxane has a drug permeation-promoting effect that is less irritating to the skin than other organic solvents.

[0025]

As described above, the percutaneous absorption enhancer (hydroxypropylated polyrotaxane) according to the present invention is
It disturbs or destroys the ordered structure of the stratum corneum, which is expected to enhance drug absorption, and does not penetrate into subcutaneous tissue below the stratum corneum, or even if it penetrates, it automatically or in the subcutaneous tissue Skin irritation due to specific decomposition
It is possible to avoid cytotoxicity and inflammatory properties. It was also found that the aqueous solution of indomethacin using the hydroxypropylated polyrotaxane according to the present invention is superior in permeability as compared with the conventional ones.

[Brief description of drawings]

1 is a graph showing the average skin permeation of an indomethacin suspension according to the present invention.

Claims (4)

[Claims] 1. A cyclic compound having a plurality of α, β or γ-cyclodextrins, a linear polymer compound penetrating a cavity of the cyclic compound, and bound to both ends of the linear polymer compound. A percutaneous absorption-promoting substance comprising a biodegradable polymer and a biodegradable polymer aggregate having a supramolecular structure obtained by hydroxypropylating the α, β or γ-cyclodextrin. 2. The transdermal skin according to claim 1, wherein the linear polymer compound penetrating the cavity of the cyclic compound is made of polyethylene glycol, polypropylene glycol, polyisobutylene or a block copolymer thereof. Absorption enhancer. 3. The following steps a to d: a) reacting carbobenzoxy-L-phenylalanine with N-hydroxysuccinimide (N-HOSu) to synthesize ZL-Phe-succinimide, b) a step of adding α- (3-aminopropyl) -ω- (3-aminopropyl) poly (oxyethylene) to an aqueous solution of cyclodextrin to prepare a pseudopolyrotaxane, and c) obtained by the step a). To the ZL-Phe-succinimide solution to synthesize the ZL-Phe-polyrotaxane obtained in the step b), and d) to obtain the ZL-Phe-polyrotaxane obtained in the step c). A process for producing a percutaneous absorption enhancer comprising the step of converting polyrotaxane into hydroxypropyl. 4. The method for producing a percutaneous absorption enhancer according to claim 3, wherein the hydroxypropylated ZL-Phe-polyrotaxane obtained in the step d) is subjected to deprotection of the Z group by a reduction method. .