JPH0122248B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to novel hyaluronic acid formulations.

Hyaluronic acid is widely distributed in the connective tissue of mammals, and its chemical structure is that of glucuronic acid and N-
Acetylglucosamine is a linear polymer with β→3-bonded repeating units. This long molecular chain forms a loose random coil in an aqueous solution, occupies a large molecular volume when hydrated, and exhibits strong viscosity. Due to these properties, hyaluronic acid plays an important role in maintaining tissue flexibility, maintaining structure, and regulating cell metabolism as a component of connective tissues such as joints, vitreous body, cartilage, skin, and umbilical cord. . Hyaluronic acid is used as a therapeutic agent for conditions such as arthritis due to its viscosity, and it is also used in anterior chamber surgery in ophthalmology, such as cataract/glaucoma surgery, corneal transplantation, and artificial lens transplantation. By injecting viscoelastic sodium hyaluronate jewelry during surgical operations, damage to the tissue surface is prevented, procedures such as suturing can be performed safely and reliably, and post-surgical clots are prevented. It is used for such purposes.

In order to fully exhibit these functions of hyaluronic acid, it is necessary for the hyaluronic acid preparation to maintain high viscosity.

Therefore, the present inventors have conducted various studies on the ingredients that should be incorporated into an aqueous solution preparation of hyaluronic acid, and have dissolved hyaluronate in water made physiologically isotonic with non-electrolytes such as polyhydric alcohol, sugar alcohol, glucose, or mannose. In particular, they succeeded in increasing the viscosity of hyaluronic acid. Moreover, by doing so, a highly viscous hyaluronic acid preparation can be obtained even when using a low concentration hyaluronate solution or a hyaluronate with a low molecular weight (normally, the higher the molecular weight of hyaluronic acid, the higher the viscosity). .

The present invention involves blending hyaluronate into an aqueous solution that has been physiologically tonicized using a non-electrolyte selected from polyhydric alcohols, sugar alcohols, glucose, and mannose, and adjusting the viscosity of the aqueous solution to 20,000 to 200,000 centipoise. It consists of a highly viscous hyaluronic acid preparation.

In the preparation of the present invention, polyhydric alcohol, sugar alcohol, glucose, or mannose is used to achieve isotonicity with body fluids. By doing so, the carboxyl group of glucuronic acid in the hyaluronic acid molecule forms an anion in the aqueous solution. This causes the anions in the hyaluronic acid molecules to repel each other, increasing the volume of the hyaluronic acid molecule, and thus maintaining high viscosity.

The hyaluronic acid used in the present invention can be widely used for medical purposes, for example, as long as it is purified to the extent that it does not cause problems when injected into the eye, and its origin is not particularly limited. Umbilical cord, vitreous body, crest, etc. can be used for this purpose. Hyaluronic acid derived from the umbilical cord and crest has an average molecular weight of approximately 1.5 million ~
2 million, and those derived from the vitreous have an average molecular weight of approximately
500,000. Examples of methods for purifying hyaluronic acid include the method described in Japanese Patent Application No. 134890/1983.

As the hyaluronate, neutral salts are preferred, and specific examples include alkali metal salts such as sodium salts and potassium salts, and alkaline earth metal salts such as calcium salts. Of such salt,
For preparations used for ophthalmology, sodium salts are appropriate, considering the salt composition of the aqueous humor.

When the preparation of the present invention is used for ophthalmology (for example, eye surgery), it is preferable to use a low-molecular-weight hyaluronate (for example, average molecular weight of about 500,000) or to use a hyaluronate in the form of a low-concentration aqueous solution. This is due to the following reasons. In other words, conventional hyaluronic acid preparations are made by dissolving molecular hyaluronate with an average molecular weight of about 2 million in physiological saline, and although they are highly viscous, when used for surgery in the ophthalmology field, for example, it is difficult to absorb the aqueous humor. It has the disadvantage that intraocular pressure often increases after surgery because of slow diffusion.
On the other hand, when the formulation of the present invention using a low-molecular-weight hyaluronate or a low-concentration hyaluronic acid aqueous solution is applied to ophthalmological surgery, the formulation that was initially jelly-like and highly viscous (during surgery) becomes Upon contact with the electrolyte in the aqueous humor of the eye, the cations derived from the electrolyte and the anions of the glucuronic acid moiety in hyaluronic acid form salts, and the repulsion between anions disappears, causing the viscosity of the jewelry to become more viscous than the surrounding area. Since it gradually decreases and is dispersed into the eye after surgery (Experimental Example 2 described later), it does not cause an increase in intraocular pressure. Nonelectrolytes used for physiological isotonicity include polyhydric alcohols such as glycerin and ethylene glycol, sugar alcohols such as sorbitol and mannitol, glucose, and mannose.

The viscosity required for hyaluronic acid preparations is 20,000 to 20
10,000 centipoise, and in order to obtain such a viscosity, when hyaluronate is dissolved in, for example, a 2.6% glycerin aqueous solution, the average molecular weight is 150 centipoise.
Hyaluronate with an average molecular weight of 50,000 to 2,000,000 has a concentration of 0.5 to 1.2%, and hyaluronate with an average molecular weight of 500,000 has a concentration of 2 to 4%.

The hyaluronic acid preparation prepared in this way has a concentration of 3/4 of that of hyaluronate with an average molecular weight of 1.5 million, and 1/4 of the concentration of hyaluronate with an average molecular weight of 500,000 compared to when dissolved in physiological saline. In the case of an acid salt, a formulation with the desired viscosity could be obtained at 1/2 the concentration (Experiment Example 1, described later).

The hyaluronic acid preparation provided by the present invention can be used for arthritis treatment, anterior segment surgery, retinal detachment treatment, etc., and is particularly preferred for ophthalmology. This preparation is generally administered locally, for example into the joint cavity, into the eyeball, etc. Preparations for topical administration are conveniently in liquid form. Formulation is carried out by adding and dissolving an appropriate amount of hyaluronate in an aqueous solution of a suitable non-electrolyte, adding a non-electrolyte to the hyaluronate to swell the hyaluronic acid, and then adding water (preferably distilled water). This is done by a method such as dissolving.

The preparation thus obtained is generally in the form of a jelly, sealed in a glass syringe, and preferably sterilized intermittently (usually at 80° to 100°C).
I do.

Next, the present invention will be explained using experimental examples and examples, but the present invention is not particularly limited to the following examples.

Experimental Example 1 An experiment was conducted to investigate the relationship between the hyaluronic acid concentration of a hyaluronate aqueous solution, the components used for isotonicity, and the viscosity. As an aqueous solution, use physiological saline or 2.6% glycerin solution with an average molecular weight of 1.5 million,
and 500,000 hyaluronic acid were used. Figure 1 shows the relationship between the concentration and viscosity of a hyaluronic acid solution.
It's like this. In Figure 1, the solid line indicates 2.6% glycerin solution, the broken line indicates physiological saline solution, the black circle indicates sodium hyaluronate with an average molecular weight of 1.5 million, and the black triangle indicates sodium hyaluronate with an average molecular weight of 500,000. The viscosity of is greatly influenced by its molecular weight, and up to a certain concentration, the viscosity gradually increases in proportion to the concentration, but beyond a certain concentration, the viscosity increases rapidly. The concentration at which the viscosity suddenly increases is determined by the molecular weight of the solvent, but it also changes depending on the composition of the solvent. That is,
When a solvent containing a non-electrolyte is used, the concentration of hyaluronic acid, whose viscosity increases rapidly, shifts to a lower concentration side, and the present invention utilizes this property.

Experimental Example 2 Sodium hyaluronate with an average molecular weight of 1.5 million and 500,000, respectively, was dissolved in a 2.6% glycerin solution and a physiological saline solution, both of which had a viscosity of 1 x 10 ⁴ centipoise, and then placed in a test tube. Figure 2 shows the rate at which hyaluronic acid diffuses into the physiological saline layer by gently layering physiological saline and removing a small amount of saline over time.

In Figure 2, the solid line indicates 2.6% glycerin solution.
The dashed line represents physiological saline, the black circle represents sodium hyaluronate with an average molecular weight of 1.5 million, and the white circle represents sodium hyaluronate with an average molecular weight of 50.
10,000 sodium hyaluronate.

It took 4 days for 50% of the hyaluronic acid gelly dissolved in physiological saline to diffuse, whereas 50% of the hyaluronic acid gelly formulation prepared in 2.6% glycerin dissolved in physiological saline within 2 days. It can be seen that the rate of diffusion differs depending on the solvent used in the preparation, even for jewelry prepared to the same viscosity. Furthermore, when the molecular weight of hyaluronic acid was small, it diffused even faster.

Example 1 Average molecular weight 220 extracted and purified from chicken comb
When 8.0 g of sodium hyaluronate is gradually added to 1.0 g of 5.05% glucose solution and stirred slowly for about 4 hours to completely dissolve, a jelly with a viscosity of 200,000 centipoise is obtained.

Example 2 26g of glycerin is added to 10g of sodium hyaluronate with an average molecular weight of 1.5 million extracted and purified from human umbilical cord, and then 970ml of distilled water at 60-70°C is added and stirred for about 4 hours to completely dissolve. A jelly with a viscosity of 200,000 centipores is obtained.

Example 3 30g of sodium hyaluronate extracted and purified from bovine vitreous body with an average molecular weight of 500,000 is gradually added to a 2.6% glycerin solution of 1.0% and stirred for about 3 hours to dissolve, resulting in a jewelery with a viscosity of 50,000 centipoise. can get.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the hyaluronic acid concentration of an aqueous hyaluronic acid solution, the components used for isotonicity, and viscosity, and Figure 2 shows the diffusion rate when the hyaluronic acid preparation of the present invention is brought into contact with an electrolyte. This is a graph comparing it with conventional products.

Claims (1)

[Claims] 1 The viscosity of the aqueous solution is adjusted to 20,000 to 200,000 centipoise by adding hyaluronate to an aqueous solution that has been made physiologically isotonic using a non-electrolyte selected from polyhydric alcohols, sugar alcohols, glucose, and mannose. A highly viscous hyaluronic acid preparation.