EP4084801A1

EP4084801A1 - A novel viscoelastic formulation for osteoarthritis treatment and a production method thereof

Info

Publication number: EP4084801A1
Application number: EP20910352.2A
Authority: EP
Inventors: Faruk OYTUN; Busra Gizem KAYA
Original assignee: VSY Biyoteknoloji ve Ilac Sanayi AS
Current assignee: VSY Biyoteknoloji ve Ilac Sanayi AS
Priority date: 2019-12-31
Filing date: 2020-12-31
Publication date: 2022-11-09
Also published as: TR201922907A2; TR201922945A2; WO2021137837A1; EP4084801A4

Abstract

The present invention relates a novel viscoelastic formulation developed for osteoarthritis treatment, and a production method thereof. The objective of the present invention is to provide a viscoelastic gel comprising crosslinked hyaluronic acid, chondroitin sulfate and non-crosslinked hyaluronic acid (Linear HA) for use in intra- articular applications to relieve pain caused by Osteoarthritis (OA), to provide support for synovial fluid whose effectiveness has decreased, and to treat osteochondral lesions.

Description

A NOVEL VISCOELASTIC FORMULATION FOR OSTEOARTHRITIS TREATMENT AND A PRODUCTION METHOD THEREOF

Field of the Invention

The present invention relates to a novel viscoelastic formulation developed to relieve pain caused by osteoarthritis (OA), to provide support to the synovial fluid whose effectiveness has decreased, and to treat osteochondral lesions, and a production method thereof.

Background of the Invention

Osteoarthritis (OA) is the most common chronic (long-term) joint disease affecting millions of people worldwide. OA is also called degenerative joint disease, degenerative arthritis, and wear and tear arthritis. The joint is where two bones come together and the ends of these bones are covered with a protective tissue called cartilage. Cartilage is a durable and slippery tissue that allows joint movement to occur almost without friction. Synovial fluid which provides lubrication between the bone ends and the cartilage is comprised of Hyaluronic Acid (HA) that is naturally present in the body. The viscosity, lubrication and shock absorbing properties of the said synovial fluid decrease over time due to mechanical effects and the cartilages begin to rub against each other and break down. As the cartilage wears off and breaks down over time, the friction between the bones increases and OA progresses. OA affects the entire joint, as well as cartilage breakdown. It causes changes in the bone structure and the deterioration of the connective tissues that hold the joint together and connect the muscles to the bone; and also causes inflammation of the joint capsule.

Even though OA is usually seen in old ages, it can sometimes be seen also in young people. OA symptoms develop over time and they worsen as it progresses. Symptoms of OA include pain, stiffness, tenderness, loss of flexibility, crepitus, osteophyte formation, and swelling.

Even though damage of the joints cannot be recovered; exercising, being at a healthy weight and several treatments that are applied can slow the progression of the disease and help relieve pain and improve joint functions.

One of the methods that can help relieve OA symptoms, especially pain, is the use of medication. The commonly used drugs and their effects are shown below: · Acetaminophen: It is known that acetaminophen (Tylenol and others) helps patients with osteoarthritis suffering from mild to moderate pain. Intake of acetaminophen more than the recommended dose may cause liver damage.

• Non-steroidal anti-inflammatory drugs (NSAIDs): NS A TPs such as Advil (ibuprofen) and Aleve (naproxen) reduce swelling as well as pain.

• Duloxetine (Cymbalta): This drug which is normally used as an antidepressant is also used to treat chronic pain, including osteoarthritis pain.

Physical therapy can also be used to alleviate OA symptoms. In addition to these, surgery and other procedures are:

• Cortisone injections: Corticosteroid drug injections may relieve the pain in the joint. During this procedure, the doctor checks the area around the joint, and then inserts a needle into the cavity in the joint and injects the drug. The number of cortisone injections which can be taken per year is generally limited to three or four injections since the drug worsens joint damage over time.

• Viscoelastic injections: HA injections may relieve pain by means of providing an amount of cushioning in the knee. Normally, hyaluronic acid is a component that naturally exists in joint fluid. • Realigning the bones: In knee osteotomy, a surgeon cuts the bone above or below the knee and then removes or inserts a wedge bone. This takes the body weight away from the worn part of the knee.

• Joint replacement: In joint replacement surgery (arthroplasty), the surgeon removes the damaged joint surfaces and replaces them with plastic and metal parts. Surgical risks include infections and blood clots. Artificial joints can wear off or become loose, and they may need to be changed eventually.

Today, the most preferred method among these treatments is to make viscoelastic injections to the problematic area. The most preferred one of these injections is the HA injections. HA is a gel-like substance naturally existing in the synovial fluid surrounding the joints. The said substance provides lubrication and cushioning, acts as a shock absorber, and helps the bones move smoothly instead of wearing each other off. Intra- articular lubricant HA injections are used to provide support for the synovial fluid to relieve pain and heal intra-articular wounds in pathological conditions. Additionally, they enable the osteoarthritic joint to regain its viscoelasticity by improving its physiological environment; they reduce friction and increase mobility. People with OA have low amounts of HA in their joint fluid. In the knee with OA, the concentration of HA decreases approximately to half of the normal level. Changes in the viscous and elastic properties of HA decrease the joint's ability to withstand tensile and shear forces. HA injections can help recover the normal levels of synovial fluid. These injections not only lubricate the joint, they can also reduce inflammation and protect the cartilage from further wear and tear.

The injections are made in weekly periods by a doctor or healthcare professional. The number of injections to be made may vary depending on the HA concentration. Before making the injection, the doctor can perform aspiration by taking some of the fluid from the knee joint with a needle in order to reduce swelling.

The hyaluronic acid which is not crosslinked (Linear HA) has several disadvantages due to its short term effect and its inability to create volume. HA is subjected to crosslinking processes with crosslinking agents such as ethyldimethylaminopropyl carbodiimide (EDC), butanediol diglycidylether (BDDE) or divinyl sulfone (DVS) in order to improve its viscoelastic properties and increase its permanence. Crosslinking reaction is an intramolecular and intermolecular esterification reaction that is performed using several reagents. It has been envisaged that by means of using this technique, the residence time of the HA formulation in the joint can be increased. The physical, chemical and biological properties of HA change significantly by increasing the degree of crosslinking. The gel suspension of crosslinked HA has different rheological properties than the linear HA. In dilute solution, the low frequency modulus of crosslinked HA is higher than the non-crosslinked HA, which indicates that a network structure has been formed for crosslinked materials. At higher concentrations, when the entangled web is formed, the constant shear viscosity or elastic modulus is not higher than non-crosslinked HA.

The residence time in the body of the linear HA viscoelastic material against the mechanical effect of the joint is shorter than the crosslinked HA. The mechanical strength of the crosslinked HA is higher than that of linear chains. While the specialist applying the treatment carries out the non-crosslinked HA (Linear HA) injection at weekly intervals, this period is longer for viscoelastics comprising crosslinked HA. For this reason, the specialist physician generally prefers injections also including crosslink having a longer residence time in the body and higher mechanical strength. It has been observed that the crosslinked viscoelastic exhibits effective results even with a single injection. In the state of the art, in cases when sodium hyaluronate is applied to the joint area, it changes the rheology of the synovial fluid, provides a quick relief in mobility and relieves pain. However, the effect of non-crosslinked HA (linear HA) which is conventionally used is temporary, because HA can only stay for 72 hours within the joint before it is absorbed or metabolized. As well as this situation does not prolong the patient's comfort period sufficiently, the damaged articular cartilage cannot be healed since the main problem is not improved.

United States patent application no US8323617B2, an application known in the state of the art, discloses that HA formulations crosslinked with carbodiimide derivative crosslinking agents are used in the treatment of OA.

European patent document no EP1443945B1, an application known in the state of the art, discloses synergistic effect of sodium hyaluronate and chondroitin sulfate mixture on the lubrication and regeneration of articular cartilage damaged by stage I and stage II osteoarthritis of human joints. In this patent application, the combination of linear HA and chondroitin sulfate was used in the treatment of osteoarthritis.

In the United States patent document no US6051560, an application known in the state of the art, chondroitin sulfate/sodium hyaluronate compositions, which are viscoelastic injections used in intraocular lens implantations, were prepared in a buffer solution, and it has been found that the strong interactions that occur between these structures exhibit increased solution stability and improved physical properties.

An article published by Falcone, S. J. et. ah, an application known in the state of the art, discloses the use of hyaluronic acid in biomedical applications, its physical properties, rheological properties and differences of cross-linked HA from linear

HA. [Falcone, S. J., Palmeri, D., & Berg, R. A. (2006). Biomedical Applications of Hyaluronic Acid. Polysaccharides for Drug Delivery and Pharmaceutical Applications, 155—174. doi: 10.1021/bk-2006-0934.ch008.]

Summary of the Invention The objective of the present invention is to provide a novel viscoelastic gel to be used in intra-articular applications in order to relieve pain caused by Osteoarthritis (OA), to provide support to the synovial fluid whose effectiveness has decreased and to treat osteochondral lesions. Another objective of the present invention is to create a synergistic effect by means of mixing chondroitin sulfate, which is a suitable substance for the regeneration of cartilage, with sodium hyaluronate.

A further objective of the present invention is to increase the residence time of chondroitin sulfate in the tissue due to its good adhesion to the tissue with positive charge due to its negative charge provided by the sulfate groups that are densely present in its structure.

Another objective of the present invention is to increase mechanical strength and residence time of the gel by means of the crosslinked HA present in the mixture.

Detailed Description of the Invention

The viscoelastic gel of the present invention has been developed to be used in intra-articular applications for the treatment of osteochondral lesions caused by Osteoarthritis (OA) and comprises a novel viscoelastic gel formulation comprised of three active ingredients. These ingredients are as follows: i. Crosslinked hyaluronic acid ii. Chondroitin sulfate iii. Non-crosslinked hyaluronic acid (Linear HA) The ingredients in the viscoelastic gel formulation of the present invention are prepared within the scope of the ratios in Table 1, and the concentrations of the active ingredients in the formulation described above are (preferably) in the following range: - Crosslinked HA : 2-12 mg/ml

- Chondroitin sulfate : 8-35 mg/ml

Non-crosslinked HA 6-20 mg/ml Table 1. Combination ratios (%) of components by weight required for crosslinked HA reaction/synthesis only

The production method of the viscoelastic gel developed within the scope of the invention is comprised of the following steps:

- Preparing 1% NaOH solution in deionized water,

- Gradually adding Hyaluronic Acid (HA) to the said solution and dissolving it,

- Adding Butanediol Diglycidylether (BDDE) to the HA mixture and mixing homogeneously, - Leaving the mixture for crosslinking reaction in a water bath at 40 °C for 1 hour,

- Cooling down the gel to room temperature after the reaction,

- Neutralizing the cooled gel mixture in phosphate buffer solution (PBS) with 0.1 M hydrochloric acid (HC1) until the pH is 6.8-7.4 (This process is continued until the pH is fixed)

- Filtering the mixture with a sieve after 6 hours and allowing the gel to further swell for 10 hours upon adding a new PBS solution,

- Successively washing the swollen gel with the new PBS solution 8-10 times more and filtering it, (This process was repeated 8-10 times in order to remove the impurities occurring during the reaction and the crosslinking agent BDDE as much as possible. The amount of BDDE should be less than 2 ppm in the final product ( a value determined by the FDA). That is, washing process was carried out many times in order to perform the purification process in the best possible manner.)

- Then, bringing the obtained gel to a particle size of 50-300 microns,

- Adding chondroitin sulfate (CS) and non-crosslinked HA (Linear HA) to cross-linked HA gel to facilitate extrusion, (This addition process is carried out with a rotational mixer for 24 hours at 12 rpm.) - Adjusting the pH of the final mixture to 7 and filling the syringes by applying vacuum,

- Applying vapor sterilization process to the syringes after filling process. The viscoelastic gel of the present invention can be specifically used for human joints suffering from stage I and stage II osteoarthritis (application site including knee, shoulder, sacroiliac, hip, ankle, elbow, interphalangeal and wrist joints) for lubrication of the joint and self-regeneration of the cartilage. Within the scope of the invention, it is aimed to create a synergistic effect by means of mixing chondroitin sulfate, which is a suitable substance for the regeneration of cartilage, with sodium hyaluronate. In addition to this effect, the crosslinked HA in the mixture enables to increase the mechanical strength of the gel and its residence time in the body. The considerable efficacy of the treatment provided by the viscoelastic gel of the present invention can be associated with the stimulation of chondrogenesis synergistically combined with the known benefits of viscoelastic treatment. Implantation of matrix of chondroitin sulfate and sodium hyaluronate can increase the continuity of naturally occurring chondrocytes and enable the damaged cartilage to self-regenerate by reconstituting its original state. Furthermore, chondroitin sulfate perfectly absorbs the positively charged tissue with the negatively charged sulfate groups inherent therein and the residence time is prolonged and therefore patient comfort is prolonged. Within the scope of the invention, combining cross-linked HA with chondroitin sulfate provides a longer duration of effectiveness compared to combinations comprising linear HA.

Chondroitin sulfate, which is also present in the synovial fluid and extracellular matrix, mechanically surrounds the cartilage tightly and with highly negatively charged sulfate groups therein, it has the ability to bind water and cations (Na⁺) to form a flexible layer to create electrostatic repulsion providing most of the resistance which causes the elasticity of compression of the cartilage.

Both chondroitin sulfate and sodium hyaluronate are glycosaminoglycans, which are generally known as mucopolysaccharides. It has been seen that upon mixing of chondroitin sulfate and sodium hyaluronate in an aqueous solution, they align and attract each other by hydrogen bonding at N-acetylamino group for a part of the molecular units. The hydrogen bonding interaction is only one of several possible interactions for chondroitin sulfate and sodium hyaluronate. Chondroitin sulfate derivative beads and hyaluronate derivative beads have the ability to interact with each other and it is assumed that this interaction takes place among the carbohydrate chains of the polymers. Adding chondroitin sulfate to sodium hyaluronate in aqueous solution significantly increases the viscosity of the mixture. It is seen that this increase in viscosity is essentially due to an increase in molecular weight rather than an increase in solute concentration. The viscosity of the solute- solvent is a function of molecular weight and solute concentration. The hydrogen bonding interaction between chondroitin sulfate and sodium hyaluronate will cause the molecular size to expand effectively. Therefore, the viscosity of the mixture will increase. The interaction between chondroitin sulfate and sodium hyaluronate can also occur at any concentration. However, the synergistic viscosity effect is more apparent at higher concentration due to the concentration effect and interaction affinity of the molecules. All these interactions show the effect of chondroitin sulfate in the formulation on non-crosslinked HA (Linear HA).

Claims

1. A novel viscoelastic formulation, which is developed for use in intra- articular applications to relieve pain caused by osteoarthritis (OA), to provide support to the synovial fluid whose effectiveness has decreased, and to treat osteochondral lesions, comprising Crosslinked hyaluronic acid (HA) which is synthesized with Hyaluronic Acid (HA), Butanediol Diglycidyl Ether (BDDE), NaOH and Deionized water, and characterized by crosslinked hyaluronic acid (HA), non-crosslinked hyaluronic acid (Linear HA) and chondroitin sulfate (CS) as active ingredients therein.

2. A novel viscoelastic formulation according to claim 1, characterized in that the synthesized crosslinked hyaluronic acid (HA) includes 7-17% by weight of Hyaluronic Acid (HA), 0.5-4% by weight of Butanediol Diglycidylether (BDDE), 1% by weight of NaOH and 80-95% by weight of Deionized water.

3. A novel viscoelastic formulation according to claim 1, characterized in that the concentrations of the active ingredients therein are 2-12 mg/ml crosslinked HA, 6-20 mg/ml non-crosslinked HA (Linear HA) and 8-35 mg/ml Chondroitin sulfate.

4. A novel viscoelastic formulation according to any one of the preceding claims which is used for lubrication of the joint and self-regeneration of the cartilage to the human joints suffering from stage I and stage II osteoarthritis.

5. A novel viscoelastic formulation according to claim 4, which is used for lubrication of the joint and self-regeneration of the cartilage to at least one of the knee, shoulder, sacroiliac, hip, ankle, elbow, interphalangeal and wrist joints of people suffering from stage I and stage II osteoarthritis.

6. Production method of a viscoelastic gel according to any one of the preceding claims, characterized in that it comprises the steps of

- preparing NaOH solution in deionized water,

- gradually adding Hyaluronic Acid (HA) to the said solution and dissolving it,

- adding butanediol diglycidylether (BDDE) to the HA mixture and mixing homogeneously,

- leaving the mixture for crosslinking reaction within the water bath,

- cooling down the gel to room temperature after the reaction,

- neutralizing the cooled gel mixture with hydrochloric acid (HC1) in phosphate buffer solution (PBS),

- filtering the mixture with sieve and allowing the gel to further swell upon adding new PBS solution,

- successively and repeatedly washing the swollen gel with new PBS solution and filtering it,

- then, bringing the obtained gel to a particle size of 50-300 microns,

- adding chondroitin sulfate (CS) and non-crosslinked HA (Linear HA) to crosslinked HA gel to facilitate extrusion,

- adjusting the pH of the final mixture to 7 and filling the syringes by applying vacuum,

- applying vapor sterilization to the syringes after filling process.

7. A viscoelastic gel production method according to claim 6, characterized by the step of preparing 1% NaOH solution in deionized water.

8. A viscoelastic gel production method according to claim 6, characterized by the step of leaving the mixture for crosslinking reaction in a water bath at 40°C for 1 hour.

9. A viscoelastic gel production method according to claim 6, characterized by the step of neutralizing the cooled gel mixture in phosphate buffer solution (PBS) with 0.1 M hydrochloric acid (HC1) until the pH is 6.8-7.4.

10. A viscoelastic gel production method according to claim 6, characterized by the step of neutralizing the mixture with HC1 in PBS until the pH value is fixed.

11. A viscoelastic gel production method according to claim 6, characterized by the step of filtering the mixture with a sieve after 6 hours and allowing the gel to further swell for 10 hours upon adding new PBS solution.

12. A viscoelastic gel production method according to claim 6, characterized by the step of successively washing the swollen gel with new PBS solution 8-10 times more and filtering it.