LOCAL ANESTHETIC ANALGESIC SUSTAINED-RELEASE DRUG DELIVERY SYSTEM, PREPARATION METHOD AND APPLICATION THEREOF

Abstract

The present invention discloses a novel local anesthetic analgesic sustained-release drug delivery system. The system includes an internal aqueous phase, an external aqueous phase, an oil phase, an organic solvent, an isoosmotic regulator and a pH regulator. The internal aqueous phase includes an analgesic, a drug solvent and a drug solubilizer. The analgesic is selected from one of bupivacaine, levobupivacaine, ropivacaine, lidocaine and tetracaine, and the analgesic is in a free base form or an acid saline form; the drug solvent is selected from inorganic acid containing N or P; and the drug solubilizer is selected from one or more of saccharide and ring-shaped organic acid. The multivesicular liposome prepared in the present invention has the advantages of high encapsulation percentage and drug loading capacity, uniform grain size, and good sustained-release effect.

Claims

1-8. (canceled)

9. A method of preparing a local anesthetic analgesic sustained-release drug delivery system, comprising: (1) preparation of internal aqueous phase dissolving analgesic with a drug solvent and a drug solubilizer if the analgesic is in a free base form; and if the analgesic is in an acid saline form, replacing the acid radical contained in the analgesic with an acid radical containing N or P, and then dissolving the analgesic with a drug solvent and a drug solubilizer; (2) preparation of external aqueous phase dissolving substances selected from one or more of saccharide, ring-shaped organic acid, organic base and deflocculant with water to obtain an external aqueous phase, wherein the organic base is used to regulate the pH value of the external aqueous phase; (3) preparation of oil phase dissolving synthetic phosphatidylcholine, synthetic phosphatidylglycerol, cholesterol and glyceride with an organic solvent to obtain an oil phase; (4) preparation of primary emulsion adding the prepared internal aqueous phase into the oil phase in a volume ratio of 1:10-10:1 of the internal aqueous phase to the oil phase, and shearing at 10,000-16,000 rpm for 5-20 min to obtain a primary emulsion; (5) preparation of multiple emulsion adding the primary emulsion into the external aqueous phase in a volume ratio of 1:5-1:50 of the primary emulsion to the external aqueous phase, shearing at 1,000-4,000 rpm for 5-60 seconds; then adding the external aqueous phase which is 5-20 times the volume of the primary emulsion, blowing with 40-90 L/min of nitrogen at 20-40 C. for 5-30 min or performing rotary evaporation at 20-40 C.; removing the organic solvent, collecting an intermediate of multivesicular liposome, centrifuging the intermediate at 100-20,000 rpm for 10-30 min; discarding a supernatant, flushing a precipitate by an isoosmotic regulator, and regulating pH to 5.0-8.0 with a pH regulator to obtain the multivesicular liposome of from 1 m to 50 m in size.

10. The method of claim 9, wherein in step (1) the analgesic is selected from one of bupivacaine, levobupivacaine, ropivacaine, lidocaine and mepivacaine; the drug solvent is selected from inorganic acid containing N or P; and the drug solubilizer is selected from one or more of saccharide and ring-shaped organic acid.

11. The method of claim 9, wherein in step (2) the saccharide is selected from dextrose, fructose or cane sugar; the ring-shaped organic acid is selected from vitamin C, nicotinic acid, gallic acid or glucuronic acid; the organic base is selected from lysine, arginine or histidine; and the deflocculant is selected from citrate, tartrate or phosphate.

12. The method of claim 9, wherein in step (3) the synthetic phospholipid is selected from one or more of DEPC, DOPC, DPPC, DSPC and DMPC; the synthetic phosphatidylglycerol is selected from one or more of DPPG, DOPG, DMPG and DSPG; the glyceride is selected from glycerol trioleate or tricaprylin; and the organic solvent is selected from one or more of trichloromethane, n-hexane and ethyl ether.

13. The method of claim 9, wherein in step (5) the isoosmotic regulator is selected from 0.9% sodium chloride injection, 5% mannitol injection, sodium lactate ringer's injection or 5% glucose injection; and the pH regulator is selected from sodium hydroxide, triethylamine, lysine, arginine or histidine.

14. The method of claim 9, wherein a formulation for preparing the local anesthetic analgesic sustained-release drug delivery system is as follows: 5 mL of internal aqueous phase in total, including 5-500 mg of analgesic, 1-5 mL of drug solvent and 5-500 mg of drug solubilizer; 100 mL of external aqueous phase in total, selected from one or more of 0.01-10 g of saccharide, 0.1-10 g of ring-shaped organic acid, 0.1-10 g of organic base and 0.1-10 g of deflocculant; 5 mL of oil phase in total, including 5-400 mg of synthetic phospholipid, 0.5-250 mg of synthetic phosphatidylglycerol, 2.5-250 mg of cholesterol and 2.5-250 mg of glyceride; and the organic solvent, selected from one or more of 0.5-50 mL of trichloromethane, 0.5-50 mL of ethyl ether and 0.5-50 mL of n-hexane.

15. The method of claim 14, wherein a formulation for preparing the local anesthetic analgesic sustained-release drug delivery system is as follows: 5 mL of internal aqueous phase in total, including 25-300 mg of analgesic, 1-5 mL of drug solvent and 25-250 mg of drug solubilizer; 100 mL of external aqueous phase in total, selected from one or more of 1-5 g of saccharide, 1-5 g of ring-shaped organic acid, 1-3 g of organic base and 1-5 g of deflocculant; 5 mL of oil phase in total, including 25-150 mg of synthetic phospholipid, 5-100 mg of synthetic phosphatidylglycerol, 5-125 mg of cholesterol and 1-150 mg of glyceride; and the organic solvent, selected from one or more of 1.5-45 mL of trichloromethane, 1.5-45 mL of ethyl ether and 1.5-45 mL of n-hexane.

16. The method of claim 9, wherein an administration route of the multivesicular liposome is local injection administration.

Description

DESCRIPTION OF DRAWINGS

[0033] FIG. 1 is an appearance diagram of a levobupivacaine multivesicular liposome under a 400 optical microscope;

[0034] FIG. 2 is an appearance diagram of a levobupivacaine multivesicular liposome under a 200 optical microscope;

[0035] FIG. 3 is a comparison diagram of mean acupuncture painless response number 48 h after administration of levobupivacaine multivesicular liposome;

[0036] FIG. 4 is a comparison diagram of mean acupuncture painless non-response number percentage (%) of to 48 h after administration of levobupivacaine multivesicular liposome.

DETAILED DESCRIPTION

[0037] The present invention will be described below in detail in combination with drawings. Described embodiments are only used for explaining the present invention, but are not intended to limit the scope of the present invention.

Embodiment 1

[0038] Prescription Ingredients

TABLE-US-00001 Type Dosage Oil Phase DEPC 30 mg DOPC 20 mg Cholesterol 25 mg DPPG 10 mg Tricaprylin 20 mg Organic Solvent Trichloromethane 3 ml Ethyl Ether 2 ml Internal Aqueous Levobupivacaine 160 mg Phase 1 Hydrochloride Injection Phosphoric Acid 3 ml (1M) Dextrose 150 mg Vitamin C 25 mg External Aqueous Nicotinic Acid 500 mg Phase Arginine Appropriate Amount Sodium Citrate 1000 mg Isoosmotic 0.9% Sodium Appropriate Regulator Chloride Amount pH Regulator 1M Natrium Appropriate Hydroxide Amount

[0039] The preparation method of the multivesicular liposome is as follows:

[0040] (1) Preparation of Internal Aqueous Phase

[0041] Weighing a certain amount of levobupivacaine hydrochloride, dissolving same in water and then adding 1M natrium hydroxide, filtering and collecting solid if there is no more insoluble substances, washing same with water for injection to neutral, drying at 60 C., adding other substances of the internal aqueous phase into the solid powder, adding 3 ml of 1M phosphoric acid, dissolving same and then adding water to 5 ml, to obtain an aqueous phase.

[0042] (2) Preparation of External Aqueous Phase

[0043] Weighing the nicotinic acid and sodium citrate of the external aqueous phase in the above table, adding 80 ml of water to dissolve same, regulating the pH to 7.4 using arginine, and adding water to 100 ml, to obtain an external aqueous phase.

[0044] (3) Preparation of Oil Phase

[0045] Weighing various substances of the oil phase in the above table, and dissolving same using 5 ml of mixed solution of trichloromethane and ethyl ether (with the volume ratio of 3:2) to obtain an oil phase.

[0046] (4) Preparation of Primary Emulsion

[0047] Adding the prepared internal aqueous phase into the oil phase, and shearing for 10 min at 13000 rpm to obtain primary emulsion.

[0048] (5) Preparation of Multiple Emulsion

[0049] Weighing 5 ml of primary emulsion, rapidly pouring 20 ml of external aqueous phase, shearing for 60 s at 3000 rpm, sequentially adding 80 ml of external aqueous phase rapidly, blowing for 20 min using 80 L/min of nitrogen, removing the organic solvent, collecting the intermediate of the multivesicular liposome, flushing using a large number of 0.9% NaCl solution, regulating the pH of the suspension of the liposome to 7.4 using 1M natrium hydroxide, and obtaining the multivesicular liposome, the mean grain size of the obtained multivesicular liposome being 30 m.

Embodiment 2

[0050] Prescription Ingredients

TABLE-US-00002 Type Dosage Oil Phase DEPC 60 mg Cholesterol 40 mg DPPG 5 mg Tricaprylin 30 mg Organic Trichloromethane 4 ml Solvent Ethyl Ether 1 ml Internal Bupivacaine 200 mg Aqueous Phase 100 mM Nitric Acid (1M) 2.5 ml Cane Sugar 200 mg Vitamin C 15 mg External Glucuronic Acid 100 mg Aqueous Phase Arginine Appropriate Amount Sodium Citrate 1500 mg Cane Sugar 50 mg Isoosmotic 0.9% Sodium Chloride Appropriate Regulator Amount pH Regulator 0.8M Triethylamine Appropriate Amount

[0051] The preparation method of the multivesicular liposome is as follows:

[0052] (1) Preparation of Internal Aqueous Phase

[0053] Weighing 200 mg of bupivacaine, adding other substances of the internal aqueous phase, adding 2.5 ml of 1M nitric acid, dissolving same and then adding water to 5 ml, to obtain an aqueous phase.

[0054] (2) Preparation of External Aqueous Phase

[0055] Weighing the glucuronic acid, cane sugar and sodium citrate of the external aqueous phase in the above table, adding 80 ml of water to dissolve same, regulating the pH to 8.0 using arginine, and adding water to 100 ml, to obtain an external aqueous phase.

[0056] (3) Preparation of Oil Phase

[0057] Weighing various substances of the oil phase in the above table, and dissolving same using 5 ml of mixed solution of trichloromethane and ethyl ether (with the volume ratio of 4:1) to obtain an oil phase.

[0058] (4) Preparation of Primary Emulsion

[0059] Adding the prepared internal aqueous phase into the oil phase, and shearing for 8 min at 16000 rpm to obtain primary emulsion.

[0060] 5) Preparation of Multiple Emulsion

[0061] Weighing 5 ml of primary emulsion, rapidly pouring 20 ml of external aqueous phase, shearing for 30 s at 2000 rpm, sequentially adding 80 ml of external aqueous phase rapidly, performing rotary evaporation at 35 C., removing the organic solvent, collecting the intermediate of the multivesicular liposome, flushing using a large number of 5% dextrose solution, regulating the pH of the suspension of the liposome to 6.8 using 0.8M triethylamine, and obtaining the multivesicular liposome, the mean grain size of the obtained multivesicular liposome being 43 m.

Embodiment 3

[0062] Prescription Ingredients

TABLE-US-00003 Type Dosage (mg/ml) Oil Phase DEPC 30 mg DSPC 10 mg Cholesterol 15 mg DSPG 3 mg Glycerol Trioleate 15 mg Organic Solvent Trichloromethane 5 ml Internal Ropivacaine 250 mg Aqueous Phase Phosphoric Acid (1M) 3.5 ml Glucuronic Acid 100 mg External Vitamin C 50 Aqueous Phase Lysine Appropriate Amount Sodium Tartrate 50 Dextrose 20 Isoosmotic Mannitol 5% Regulator pH Regulator 0.2M Lysine Appropriate Amount

[0063] The preparation method of the multivesicular liposome is as follows:

[0064] (1) Preparation of Internal Aqueous Phase

[0065] Weighing 250 mg of ropivacaine, adding other substances of the internal aqueous phase, adding 3.5 ml of 1M phosphoric acid, dissolving same and then adding water to 5 ml, to obtain an aqueous phase.

[0066] (2) Preparation of External Aqueous Phase

[0067] Weighing the vitamin C, cane sugar and sodium tartrate of the external aqueous phase in the above table, adding 80 ml of water to dissolve same, regulating the pH to 8.5 using lysine, and adding water to 100 ml, to obtain an external aqueous phase.

[0068] (3) Preparation of Oil Phase

[0069] Weighing various substances of the oil phase in the above table, and dissolving same using 5 ml of trichloromethane to obtain an oil phase.

[0070] (4) Preparation of Primary Emulsion

[0071] Adding the prepared internal aqueous phase to the oil phase, and shearing for 10 min at 13000 rpm to obtain primary emulsion.

[0072] (5) Preparation of Multiple Emulsion

[0073] Weighing 5 ml of primary emulsion, rapidly pouring 20 ml of external aqueous phase, shearing for 15 s at 3000 rpm, sequentially adding 80 ml of external aqueous phase rapidly, performing rotary evaporation at 37 C., removing the organic solvent, collecting the intermediate of the multivesicular liposome, flushing using a large number of 5% mannitol solution, regulating the pH of the suspension of the liposome to 7.2 using 0.2M lysine, and obtaining the multivesicular liposome, the mean grain size of the obtained multivesicular liposome being 24 m.

Embodiment 4

[0074] Prescription Ingredients

TABLE-US-00004 Type Dosage Oil Phase DOPC 55 mg Cholesterol 30 mg DOPG 15 mg Glycerol Trioleate 10 mg Organic Solvent Trichloromethane 1 ml Ethyl Ether 4 ml Internal Aqueous Lidocaine 300 mg Phase 120 mM Nitric Acid (1M) 4 ml Vitamin C 50 mg Nicotinic Acid 30 mg External Aqueous Vitamin C 300 mg Phase Glucuronic Acid 200 mg Histidine Appropriate Amount Sodium Dihydrogen 400 mg Phosphate Dextrose 2000 mg Isoosmotic Sodium Lactate Appropriate Amount Regulator Ringer's Solution pH Regulator 0.5M Arginine Appropriate Amount

[0075] The preparation method of the multivesicular liposome is as follows:

[0076] (1) Preparation of Internal Aqueous Phase

[0077] Weighing 300 mg of lidocaine, adding other substances of the internal aqueous phase, adding 4 ml of 1M nitric acid, dissolving same and then adding water to 5 ml, to obtain an aqueous phase.

[0078] (2) Preparation of External Aqueous Phase

[0079] Weighing the vitamin C, glucuronic acid, sodium dihydrogen phosphate and dextrose of the external aqueous phase in the above table, adding 80 ml of water to dissolve same, regulating the pH to 9.0 using histidine, and adding water to 100 ml, to obtain an external aqueous phase.

[0080] (3) Preparation of Oil Phase

[0081] Weighing various substances of the oil phase in the above table, and dissolving same using 5 ml of mixed solution of trichloromethane and ethyl ether (with the volume ratio of 1:4) to obtain an oil phase.

[0082] (4) Preparation of Primary Emulsion

[0083] Adding the prepared internal aqueous phase into the oil phase, and shearing for 10 min at 10000 rpm to obtain primary emulsion.

[0084] (5) Preparation of Multiple Emulsion

[0085] Weighing 5 ml of primary emulsion, rapidly pouring 20 ml of external aqueous phase, shearing for 15 s at 4000 rpm, sequentially adding 80 ml of external aqueous phase rapidly, water bathing at 35 C., blowing for 15 min using 100 L/min of nitrogen, removing the organic solvent, collecting the intermediate of the multivesicular liposome, flushing using a large number of sodium lactate ringer's solution, regulating the pH of the suspension of the liposome to 7.4 using 0.5M arginine, and obtaining the multivesicular liposome, the mean grain size of the obtained multivesicular liposome being 45 m.

Embodiment 5

[0086] Prescription Ingredients

TABLE-US-00005 Type Dosage Oil Phase DMPC 80 mg Cholesterol 50 mg DMPG 3 mg Tricaprylin 30 mg Organic Solvent N-hexane 3 ml Ethyl Ether 2 ml Internal Aqueous Mepivacaine 180 mg Phase 120 mM Phosphoric Acid (1M) 3 ml Vitamin C 50 mg External Aqueous Glucuronic Acid 600 mg Phase Lysine Appropriate Amount Disodium Hydrogen 500 mg Phosphate Isoosmotic 5% Dextrose Appropriate Amount Regulator pH Regulator 0.2M Histidine Appropriate Amount

[0087] The preparation method of the multivesicular liposome is as follows:

[0088] (1) Preparation of Internal Aqueous Phase

[0089] Weighing 180 mg of mepivacaine, adding other substances of the internal aqueous phase, adding 3 ml of 1M phosphoric acid, dissolving same and then adding water to 5 ml, to obtain an aqueous phase.

[0090] (2) Preparation of External Aqueous Phase

[0091] Weighing the glucuronic acid and disodium hydrogen phosphate of the external aqueous phase in the above table, adding 100 ml of water to dissolve same, regulating the pH to 7.0 using lysine, adding water to 150 ml, to obtain an external aqueous phase.

[0092] (3) Preparation of Oil Phase

[0093] Weighing various substances of the oil phase in the above table, dissolving same using 5 ml of mixed solution of n-hexane and ethyl ether (with the volume ratio of 3:2) to obtain an oil phase.

[0094] (4) Preparation of Primary Emulsion

[0095] Adding the prepared internal aqueous phase into the oil phase, and shearing for 20 min at 16000 rpm to obtain primary emulsion.

[0096] (5) Preparation of Multiple Emulsion

[0097] Weighing 5 ml of primary emulsion, rapidly pouring 30 ml of external aqueous phase, shearing for 60 s at 4000 rpm, sequentially adding 120 ml of external aqueous phase rapidly, water bathing at 30 C., performing rotary evaporation, removing the organic solvent, collecting the intermediate of the multivesicular liposome, flushing using a large number of 5% dextrose solution, and regulating the pH of the suspension of the liposome to 7.4 using 0.2M histidine, and obtaining the multivesicular liposome, the mean grain size of the obtained multivesicular liposome being 15 nm.

Embodiment 6

[0098] Prescription Ingredients

TABLE-US-00006 Type Dosage Oil Phase DEPC 30 mg DMPC 25 mg Cholesterol 11 mg DPPG 0.5 mg DSPG 0.8 mg Tricaprylin 6 mg Organic Solvent N-hexane 3 ml Trichloromethane 2 ml Internal Aqueous Levobupivacaine 220 mg Phase 80 mM Nitric Acid (1M) 2 ml Vitamin C 100 mg External Aqueous Vitamin C 800 mg Phase Arginine Appropriate Amount disodium hydrogen 600 mg for each phosphate + sodium dihydrogen phosphate Cane Sugar 100 mg Isoosmotic 0.9% Sodium Chloride Appropriate Regulator Amount pH Regulator 0.1M Natrium Appropriate Hydroxide Amount

[0099] The preparation method of the multivesicular liposome is as follows:

[0100] (1) Preparation of Internal Aqueous Phase

[0101] Weighing 220 mg of levobupivacaine, adding other substances of the internal aqueous phase, adding 2 ml of 1M phosphoric acid, dissolving same and then adding water to 5 ml, to obtain an aqueous phase.

[0102] (2) Preparation of External Aqueous Phase

[0103] Weighing the vitamin C, cane sugar, disodium hydrogen phosphate and sodium dihydrogen phosphate of the external aqueous phase in the above table, adding 100 ml of water to dissolve same, regulating the pH to 7.0 using arginine, and adding water to 150 ml, to obtain an external aqueous phase. [0104] (3) Preparation of Oil Phase

[0105] Weighing various substances of the oil phase in the above table, and dissolving same using 5 ml of mixed solution of n-hexane and trichloromethane (with the volume ratio of 3:2) to obtain an oil phase.

[0106] (4) Preparation of Primary Emulsion

[0107] Adding the prepared internal aqueous phase into the oil phase, and shearing for 10 min at15000 rpm to obtain primary emulsion.

[0108] 5) Preparation of Multiple Emulsion

[0109] Weighing 5 ml of primary emulsion, rapidly pouring 30 ml of external aqueous phase, shearing for 25 s at 8000 rpm, sequentially adding 120 ml of external aqueous phase rapidly, water bathing at 35 C., performing rotary evaporation, removing the organic solvent, collecting the intermediate of the multivesicular liposome, flushing using a large number of 0.9% sodium chloride solution, regulating the pH of the suspension of the liposome to 7.0 using 0.1M natrium hydroxide, and obtaining the multivesicular liposome, the mean grain size of the obtained multivesicular liposome being 18 m.

Embodiment 7

[0110] Microstructure Observation of Levobupivacaine Multivesicular Liposome

[0111] The levobupivacaine multivesicular liposome is prepared in accordance with the above-mentioned embodiment 1: take a drop of multivesicular liposome on the glass slide, cover the cover slip, observe under 400 microscope and 200 microscope, and shoot the microstructure diagram of the levobupivacaine multivesicular liposome, as shown in FIG. 1 and FIG. 2. The atlas shows that the multivesicular liposome is rounding spheroid in shape, and comprises multiple small vesicles therein. The envelope is complete and clearly visible, and the entire microstructure grain size is uniform.

Embodiment 8

[0112] Determination of Content and Encapsulation Percentage of Levobupivacaine Multivesicular Liposome

[0113] The content of the levobupivacaine multivesicular liposome is determined using high performance liquid chromatography, wherein the chromatographic conditions are as follows:

[0114] Chromatographic column: Agilent C18 column (150 mm*4.6 mm*5 m); The mixed solution of 0.02 mol/L phosphate buffered saline (weighing 2.72 g of potassium dihydrogen phosphate and 0.75 g of natrium hydroxide, adding 1000 ml of water to dissolve same, and regulating the pH value to 8.0)-acetonitrile (50:50) is used as a mobile phase; the detection wavelength is 240 nm; the flow velocity is 1.0 ml/min; the column temperature is 35 C., and the injection volume is 20 l. The resolution between the levobupivacaine peak and an impurity peak adjacent thereto should be greater than 1.5.

[0115] The specific method for determination of the encapsulation percentage of the levobupivacaine multivesicular liposome is as follows:

[0116] precisely measuring 1.0 ml of suspension of levobupivacaine multivesicular liposome, adding 1.0 ml of 0.9% NaCl solution, precisely transferring 0.1 ml after blending, placing same in 10 ml of volumetric flask, adding 2 ml of methanol, performing demulsification and vibration and diluting same to the scale using the mobile phase, and shaking well; determining the total dosage (W.sub.total) in the levobupivacaine multivesicular liposome using HPLC; centrifuging other samples for 10 min at 3000 rpm, precisely transferring 0.1 ml of supernatant, placing same in 10 ml of volumetric flask, adding 2 ml of methanol to perform demulsification and vibration, diluting same to the scale using the mobile phase, shaking well, sucking 20 l, operating in accordance with the above-mentioned chromatographic condition, and determining the content of free drug in the levobupivacaine multivesicular liposome (W.sub.supernatant).

[0117] The encapsulation percentage (EE %) of the levobupivacaine multivesicular liposome is computed in accordance with the formula: encapsulation percentage (EE %)=(W.sub.totalW.sub.supernatant)/W.sub.total100%. The encapsulation percentage of the multivesicular liposome in the embodiment is determined in accordance with the above-mentioned method, see the following table:

TABLE-US-00007 Encapsulation Embodiments Percentage (%) Embodiment 1 85 Embodiment 2 91 Embodiment 3 93 Embodiment 4 90 Embodiment 5 85 Embodiment 6 82

Embodiment 9

[0118] Pesticide Effect Comparison of Levobupivacaine Multivesicular Liposome

[0119] 30-week guinea pigs which are 300-500 g in weight and are male are used as experimental animals. Before the experiment, the guinea pigs should have a rest-cure for 3 days in an independent environment at the room temperature of (231) C. under 12-12 h bright/dark illumination (illumination is at 8:00 a.m) to adapt to the environment.

[0120] Experimental method: the hair on 6 cm10 cm of back skin of guinea pigs (nine) is completely shaved. The herpes range is marked, and 4 regions are marked for each guinea pig, wherein the upper left region indicates normal saline, the upper right region indicates blank multivesicular liposome, the left lower region indicates levobupivacaine hydrochloride injection, and the lower right region indicates self-control levobupivacaine multivesicular liposome. The experiment is divided into three dosage groups, i.e. low dosage group 10 mg/ml, middle dosage group 15 mg/ml, and high dosage group 20 mg/ml, each group including three guinea pigs. The injection volume of intradermal injection for administration of each marked region is 0.35 ml. Subcutaneous herpes is formed, and the response of the guinea pigs to acupuncture is tested after 15 min. Each herpes is acupunctured for 17 times, wherein the acupuncture interval is 3-5 s, and the test time point are respectively: 1 min, 15 min, 30 min, 3 h, 6 h, 9 h, 12 h, 18 h, 21 h, 24 h, 30 h and 48 h after injection, 12 time points in total. Each guinea pig is acupunctured for 204 times in total in each region, and the acupuncture to which the guinea pigs cannot respond is counted. The number of acupuncture not making a response at the 12 time points within 48 h is accumulated, and the degree of anesthesia is reflected through the value formed by taking the sum as a numerator and the total acupuncture number 204 as a denominator. The mean percentage of number of times of non-response of each group of guinea pigs is computed, the bigger the value is, the stronger the anesthetic effect is; the smaller the computation value is, the weaker the anesthetic effect is. See Table 1 and FIG. 2 for result of mean acupuncture number 48 h after administration of levobupivacaine multivesicular liposome in low dosage group, middle dosage group and high dosage group at different time points. See Table 2 and FIG. 3 for result of mean acupuncture painless response number percentage (%) of

TABLE-US-00008 TABLE 1 Statistical Table of Mean Acupuncture Number of Levobupivacaine Multivesicular Liposome at Different Time Points Experimental Group 1 min 15 min 30 min 3 h 6 h 9 h 12 h 18 h 21 h 24 h 30 h 48 h Normal Saline 0 0 0 0 0 0 0 0 0 0 0 0 Blank Multivesicular Liposome 0 0 0 0 0 0 0 0 0 0 0 0 Levobupivacaine Hydrochloride Injection 17 17 17 7.33 0 0 0 0 0 0 0 0 Levobupivacaine Multivesicular Liposome 17 17 17 17 17 17 17 16 13 10 5 0 (10 mg/ml) Levobupivacaine Multivesicular Liposome 17 17 17 17 17 17 17 17 15 11 6 0 (15 mg/ml) Levobupivacaine Multivesicular Liposome 17 17 17 17 17 17 17 17 17 13 8 1 (20 mg/ml)

TABLE-US-00009 TABLE 2 Result of Mean Painless Response Number Percentage (%) of Levobupivacaine Multivesicular Liposome at Different Time Points Experimental Group Levobupivacaine Levobupivacaine Levobupivacaine Blank Levobupivacaine Multivesicular Multivesicular Multivesicular Normal Multivesicular Hydrochloride Liposome Liposome Liposome Saline Liposome Injection (10 mg/ml) (15 mg/ml) (20 mg/ml) Mean Painless Response Number 0 0 0.2859 0.7990 0.8235 0.8578 Mean Painless Response Number 0 0 28.59 79.9 82.35 85.78 Percentage (%)

[0121] The pharmacodynamic experiment of the levobupivacaine multivesicular liposome demonstrates that the acupuncture painless response number (10 mg/ml: 79.90%; 13.3 mg/ml: 82.35%; 20 mg/ml: 85.78% respectively) of the levobupivacaine multivesicular liposome within 48 hours is apparently higher than that of levobupivacaine hydrochloride injection (28.59%), and the action duration is greater than 24 hours. Therefore, it can be implemented that levobupivacaine is prepared into multivesicular liposome suspension with a sustained release function and then is used for postoperative analgesia.

[0122] The above is just preferred embodiments of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and the principle of the present invention shall be contained within the protection scope of the present invention.