JPH09263535A - Skin-permeable preparation for external use of indometacin using supermolecular structural polymeric aggregate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a skin-permeable preparation for external use of indometacin capable of avoiding the skin irritation or toxicity while enhancing the medicinal absorptivity of the skin by using a high-molecular organic compound. SOLUTION: This skin-permeable preparation for external use of indometacin is obtained by adding a supermolecular structural biodegradable polymeric aggregate comprising plural cyclic compounds of α-, β- and γ-cyclodextrins, a linear polymer passing through cavities of the cyclic compounds and biodegradable sites bonded to both terminals of the linear polymer to the indomethacin. The relationship among the α-, β- and γ-cyclodextrins and the polymer passing through the voids of the cyclodextrins is preferably as follows: Polyethylene glycol is used in the case of the α-cyclodextrin; polyethylene glycol, polypropylene glycol or polyisobutylene is used in the case of the β-cyclodextrin and polyethylene glycol, polypropylene glycol, polyisobutylene or polymethyl vinyl ether, etc., are used in the case of the γ-cyclodextrin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an indomethacin external preparation for the purpose of anti-inflammatory and analgesia having a transdermal absorption promoting function.

[0002]

2. Description of the Related Art External preparations relating to indomethacin are invented and known in many forms such as poultices, creams, solutions and ointments. These external preparations use a percutaneous absorption enhancer or try to permeate the skin in a state where ethanol is dissolved. For a transdermal absorption system (TTS) that efficiently absorbs a drug from the skin and exerts a local pharmacological effect, it is essential to improve the skin absorbability of the drug by using a transdermal absorption enhancer. Generally, the outer layer of the skin is covered with keratinocytes, which are called horny layer and differentiated into keratinocytes, and then are heavily responsible, and play a role of protecting not only drugs but also recent invasion of foreign substances from the outside world. 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.

[0003]

However, these percutaneous absorption enhancers simply penetrate into the body under the stratum corneum, specifically the dermis and subcutaneous tissues, resulting in skin irritation and skin toxicity. Had the problem of showing. All of the conventionally used percutaneous absorption enhancers are low molecular weight organic compounds that not only interact with keratinocytes but also penetrate into the tissues under the skin and strongly act on the cells that make up these tissues. It was found that long-term use causes cytotoxicity and subcutaneous inflammation. For this reason, new approaches have been taken in search of safe transdermal absorption enhancers. 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 biomolecular degradable polymer assembly having a supramolecular structure composed of biodegradable sites bonded to both ends of this linear polymer compound is added to indomethacin This object is achieved by a skin-permeable external preparation for indomethacin using the body. Also, α, β or γ-
The relationship between cyclodextrins and the polymers that penetrate the voids of these cyclodextrins has already been investigated by Dr. Harada of Osaka University (Surface and colloid conferences 1994 Vol. 32).
No. 2) points out that the following polymers can penetrate. 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 external preparation of the present invention, the supramolecular percutaneous absorption enhancer is polyethylene glycol, which is a linear polymer,
Cyclodextrin penetrating polypropylene glycol or these block co-polymers interacts with the stratum corneum component by a strong hydrogen bonding property to enhance drug diffusion, and depending on the molecular form of the supramolecular transdermal absorption enhancer, Cyclodextrin is polyethylene glycol, polypropylene glycol or block co-polymerization of these due to degradation of oligopeptide chains, oligosaccharide chains or ester groups, which do not penetrate subcutaneously or after subcutaneous penetration It is detached from the united body 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).

Example 2 A skin permeation test of indomethacin was conducted using the hydroxypropylated ZL-Phe-polyrotaxane obtained in the above Example as a transdermal absorption enhancer. Preparation of drug solution 12.1% of hydroxypropylated ZL-Phe-polyrotaxane
An aqueous solution (the present invention) was prepared, and purified water (Comparative Example 1) and PBS (potassium hydrogen phosphate) (pH: 7.4, 0.14) were used as Comparative Examples.
M) (Comparative Example 2) was prepared.

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, an indomethacin suspension (about twice the saturated solubility was added to PBS) was placed on the donor side, and 2.5 ml of PBS was placed on the receiver side, respectively, by a magnetic stirrer. A permeation test was carried out at 37 ° C. for 8 hours with stirring. 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 a sample To 500 μl of a sample solution, 500 μl of an internal standard solution (methanol solution of mefenamic acid, 10 μg / ml) was added and mixed, followed by centrifugation.
(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.

[0019]

[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 with 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.

[0021]

[Table 2]

[0022]

As described above, the treatment of the skin surface of the hydroxypropylated polyrotaxane according to the present invention as a percutaneous absorption enhancer increases the permeation amount of indomethacin used. It has been found that it is effective to use a liquid formulation containing polyrotaxane as a percutaneous absorption enhancer as an external preparation.

[Brief description of drawings]

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

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Claims (3)

[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 skin-penetrating indomethacin external preparation using a supramolecular structural polymer aggregate, characterized in that a biodegradable polymeric aggregate having a supramolecular structure composed of biodegradable sites is added to indomethacin. 2. The supramolecule 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. A skin-penetrating indomethacin external preparation using a biodegradable polymer aggregate having a structure. 3. The supramolecular structure polymer aggregate according to claim 2, wherein the polyethylene glycol, polypropylene glycol, polyisobutylene or block copolymer thereof has an average molecular weight of 200 to 5000, preferably 400 to 2000. Skin-permeable external preparation for indomethacin.