CN104208014A - Thermo-sensitive in-situ gel for articular cavity injection and preparation method thereof - Google Patents

Abstract

The invention mainly provides a temperature-sensitive in-situ gel for joint cavity injection and a preparation method thereof. The gel is formed by physical cross-linking of biodegradable polymers loaded with drugs. High molecular polymers are composed of hyaluronic acid and temperature-sensitive materials connected by chemical bonds. When the temperature is lower than body temperature, the drug can be wrapped or dispersed in the polymer to form a nano-gel suspension, and the temperature at the injection site of the joint cavity will increase. At body temperature, the formulation transforms from a nanosuspension to an in situ gel. The gel agent of the invention does not need chemical cross-linking, has high safety, can make non-steroidal anti-inflammatory drugs and hyaluronic acid exert a synergistic therapeutic effect, reduce toxic and side effects, and improve patient compliance.

Description

Thermosensitive in situ gel for intra-articular injection and preparation method thereof

technical field

The invention belongs to the technical field of medicine and provides a temperature-sensitive in-situ gel for intra-articular injection and a preparation method thereof.

Background technique

Non-steroidal anti-inflammatory drugs (NSAIDs) have been widely used in the treatment of arthritis, mainly by inhibiting cyclooxygenase (COX), thereby inhibiting the synthesis of prostaglandins to achieve anti-inflammatory and analgesic effects. However, the NSAIDs currently used clinically are mainly oral preparations, and patients are prone to gastrointestinal adverse reactions after long-term use, and there are certain damages to the liver, kidneys and cardiovascular system.

Intra-articular injection can directly act on the target site of the drug, increase the local concentration, avoid the physiological transport barrier in the body, change the distribution mode of the drug, exert the drug effect in a small dose, and reduce the toxic and side effects of systemic administration. widely used in therapy. This preparation has many advantages: slow-release and long-acting; it can reduce the clearance rate of drugs in the joint cavity; it can reduce the irritation of large doses of drugs; it can avoid infection after repeated administration; Toxic and side effects etc. This type of preparation is injected once every few days or even several months, which significantly enhances the effectiveness and safety of the drug and improves patient compliance. Patents CN100594029, CN101112378 and CN101940587B all disclose methods for treating arthritis by intra-articular injection.

A temperature-sensitive in situ gel is a gel that undergoes a phase transition depending on temperature. It is a free-flowing liquid under storage conditions. After being injected into the human body, it can fill the interstitial space, undergo a phase transition rapidly, and form a semi-solid gel at the injection site, achieving the purpose of local administration or delayed drug release. It has the advantages of injectability, less trauma, convenient administration, controlled drug release, etc., and is suitable for local injection in vivo. Poloxamer is the most studied polymer material for preparing temperature-sensitive in situ gels. Most of the main matrix materials of the temperature-sensitive gels reported in current patents and literature are Ploxamer 407 (trade name: F127), such as CN1230108A, CN101185650A, CN1593386A, CN1377706A, CN100422268C, CN02109503.5, etc. Among them, the F127 aqueous solution with a concentration of 20%-30% has the property of reverse gelation when heated, that is, it is a free-flowing liquid at refrigerated temperature, and forms a clear gel at room temperature or body temperature.

Intra-articular injection of hyaluronic acid is a common method for the treatment of arthritis. At present, hyaluronic acid intra-articular injections commonly used in clinic include Hyalgan, Artz, NRD-101, Hylan G-F20, etc. Among them, Hylan G-F20 is a hyaluronic acid gel injection produced by Genzyme Company of the United States. Patents CN02822420.5, US2006003964 and CN101112381A all disclose methods for intra-articular administration of hyaluronic acid to treat arthritis. However, only a single hyaluronic acid ordinary gel injection still has certain defects, such as a short residence time in the body and is easily degraded by HA enzyme; it is difficult to use after forming a gel in vitro; it does not contain therapeutic drugs and has no effect Slower wait. Therefore, it is particularly important to modify the structure of hyaluronic acid to prepare drug-loaded sustained-release preparations. Literature and other studies have also reported that the combined treatment of hyaluronic acid and NSAIDs can rapidly improve the clinical symptoms of arthritis patients, and can significantly reduce the dosage of NSAIDs while maintaining good curative effect.

Contents of the invention

The purpose of the present invention is to provide a temperature-sensitive in situ gel preparation for intra-articular injection, so as to reduce adverse drug reactions, reduce the number of administrations, facilitate use, improve patient compliance, and exert better synergistic treatment The effect of arthritis. The gel of the present invention is formed by physical cross-linking of biocompatible and biodegradable polymers loaded with drugs.

Another object of the present invention is to provide a method for preparing a temperature-sensitive in-situ gel loaded with drugs.

The above-mentioned high-molecular polymer is formed by connecting hyaluronic acid and temperature-sensitive materials through chemical bonds. The temperature-sensitive material is chitosan, polylactic acid-glycolic acid, puloxamer or isopropylacrylamide, among which puloxamer 407 and puloxamer 188 are preferred.

Among the above polymers, the molecular weight of hyaluronic acid is 500,000-5 million Daltons, preferably 700,000-2 million Daltons.

Among the above polymers, the molar ratio of poloxamer to hyaluronic acid is between 10:1-1:10, preferably between 2:1-1:5.

The above drugs are non-steroidal anti-inflammatory drugs, including diclofenac, meloxicam, etodolac, ketoprofen, indomethacin, celecoxib, nabumetone, rofecoxib one or a combination of several.

In the above thermosensitive gel, the drug can be encapsulated or dispersed in the polymer. The concentration and drug loading of the polymer are not limited unless the gelation behavior of the polymer is affected, making it impossible to form a gel or limiting its clinical use.

The above-mentioned gel has the property of temperature-sensitive reverse gelling. When the temperature is lower than body temperature, it exists in the form of nano-suspension. When the temperature of the injection site rises to body temperature, the preparation changes from nano-suspension to gel, which prolongs the life of the drug. release time.

The present invention is achieved through the following technical scheme. Proxamer is linked to the main chain of hyaluronic acid to form an amphiphilic copolymer. Under the condition that the temperature is lower than 30°C, the polymer solution entraps drugs through self-assembly , to prepare nanogel suspensions. Then, the nanogel is injected into the joint cavity to form an in situ gel at body temperature.

Description of drawings

Figure 1 shows the effect of temperature on (a) particle size and (b) equilibrium swelling rate of nanogel suspensions.

Figure 2 is the transmission electron micrographs of the temperature-sensitive nanogel suspension at (a) 4°C and (b) 37°C.

Figure 3 shows the drug release behavior of thermosensitive nanogels at different temperatures.

Detailed ways

The present invention will be described in more detail through specific examples below, but the scope of the present invention is not limited to the following examples.

Example 1

The activated proxamer F127 and hyaluronic acid were dissolved in deionized water at a molar ratio of 1:5, copper sulfate and sodium ascorbate were added, and the reaction was carried out at 40°C under nitrogen protection for 48 hours. After the reaction, dialyze in deionized water for 3 days with a dialysis bag with a molecular weight cut-off of 25 kDa, and freeze-dry to obtain the polymer. The polymer was suspended in PBS buffer (pH 7.4), and the probe was sonicated for 6 minutes (working power 90W, working pulse was working for 1s and pausing for 5s), and a blank nanogel suspension was obtained. The state of the nanogel suspension at different concentrations and temperatures was determined (Figure 1). Dissolve rofecoxib in DMF solution, dissolve the copolymer in formamide solution, mix after stirring overnight, dialyze with PBS buffer solution (pH 7.4) for 12h, centrifuge to take supernatant, filter and freeze-dry to obtain Drug-loaded thermosensitive nanogel suspension.

Example 2

The activated proxamer F68 and hyaluronic acid were dissolved in deionized water at a molar ratio of 1:2, copper sulfate and sodium ascorbate were added, and the reaction was carried out at 40°C under nitrogen protection for 48 hours. After the reaction, dialyze in deionized water for 3 days with a dialysis bag with a molecular weight cut-off of 25 kDa, and freeze-dry to obtain the polymer. The polymer was suspended in PBS buffer (pH 7.4), and the probe was sonicated for 6 minutes (working power 90W, working pulse was working for 1s and pausing for 5s), and a blank nanogel suspension was obtained, and the morphology was observed under a transmission electron microscope (Fig. 2). Dissolve indomethacin in DMF solution, copolymer in formamide solution, mix after stirring overnight, dialyze with PBS buffer (pH 7.4) for 12 hours, centrifuge to get supernatant, filter and lyophilize to obtain Drug-loaded thermosensitive nanogel suspension.

Example 3

The activated proxamer F127 and hyaluronic acid were dissolved in deionized water at a molar ratio of 1:4, copper sulfate and sodium ascorbate were added, and the reaction was carried out at 40°C under nitrogen protection for 48 hours. After the reaction, dialyze in deionized water for 3 days with a dialysis bag with a molecular weight cut-off of 25 kDa, and freeze-dry to obtain the polymer. Celecoxib was dissolved in DMF solution, the copolymer was dissolved in formamide solution, stirred overnight and mixed, then dialyzed with PBS buffer solution (pH 7.4) for 12 hours, centrifuged to take supernatant, filtered and freeze-dried to obtain Drug-loaded thermosensitive nanogel suspension. The drug release behavior at different temperatures is shown in Figure 3.

Claims (9)

1. the agent of injections in articular cavity temperature sensitive type in-situ gel, is characterized in that, this gel is formed by the mode of physical crosslinking by the biocompatibility of bag medicine carrying thing and the high molecular polymer of biodegradability.

2. thermosensitive hydrogel according to claim 1, is characterized in that, high molecular polymer is formed by connecting by chemical bond by hyaluronic acid and temperature sensing material, and wherein, temperature sensing material is chitosan, poly lactic-co-glycolic acid, Pu Luoshamu or N-isopropylacrylamide.

3. thermosensitive hydrogel according to claim 2, is characterized in that, the preferred Pu Luoshamu 407 of temperature sensing material and LUTROL micro 68 MP.

4. thermosensitive hydrogel according to claim 1, is characterized in that, hyaluronic molecular weight is 500,000-500 ten thousand dalton, preferably 70 Wan – 2,000,000 dalton.

5. thermosensitive hydrogel according to claim 1, is characterized in that, Pu Luoshamu and hyaluronic acid react mol ratio between 10:1 – 1:10, between preferred 2:1 – 1:5.

6. thermosensitive hydrogel according to claim 1, it is characterized in that, medicine is non-steroidal anti-inflammatory class medicine, wherein, comprises the one or more combination of diclofenac, meloxicam, etodolac, ketoprofen, indomethacin, celecoxib, nabumetone, rofecoxib.

7. thermosensitive hydrogel according to claim 1, is characterized in that, medicine can wrap up or be scattered in polymer.Concentration and the drug loading of polymer are unrestricted, unless had influence on the gelling behavior of polymer, make it can not form gel or limit its Clinical practice.

8. thermosensitive hydrogel according to claim 1, it is characterized in that, this gel has responsive to temperature reverse cementitious propert, when temperature is lower than body temperature, exist with nanosuspension form, in injection site, temperature is increased to body temperature, and preparation is transformed into gel by nanosuspension, the release time of prolong drug.

9. the preparation method of injections in articular cavity temperature sensitive type in-situ gel according to claim 1, it is characterized in that, Pu Luoshamu is linked in hyaluronic acid backbone, form amphipathic copolymer, temperature is lower than under the condition of 30 DEG C, polymer solution, by self assembly bag medicine carrying thing, prepares nanogel suspension.Then, nanogel is expelled in articular cavity, under temperature, forms situ-gel.