# US 2019/0314281 A1 · Local anesthetic analgesic sustained-release drug delivery system, preparation method and application thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0314281 A1 - Document ID: US20190314281A1 - Status: Published application - Kind: A1 - Application number: 16/106,414 - Filed: 2018-08-21 - Published: 2019-10-17 - Earliest claimed: 2018-04-11 - Assignees: Xi'an Libang Biomedical Technology Co.,Ltd. - Applicants: Xi'an Libang Biomedical Technology Co.,Ltd. - Inventors: Yufan Ma; Tao Chen; Danfeng Kong - Web page: https://patentgrep.com/patent/US20190314281A1 ## CPC - A61K 9/1277: Preparation processes; Proliposomes - A61K 9/0019: {Injectable compositions; Intramuscular, intravenous, arterial, subcutaneous administration; Compositions to be administered through the skin in an invasive manner (non-active ingredients are additionally classified in A61K47/00)} - A61K 9/113: Multiple emulsions, e.g. oil-in-water-in-oil {(A61K9/0026 takes precedence)} - A61K 9/127: Synthetic bilayered vehicles, e.g. liposomes or liposomes with cholesterol as the only non-phosphatidyl surfactant - A61K 31/167: having the nitrogen of a carboxamide group directly attached to the aromatic ring, e.g. lidocaine, paracetamol - A61K 31/445: Non condensed piperidines, e.g. piperocaine - A61K 47/24: containing atoms other than carbon, hydrogen, oxygen, halogen, nitrogen or sulfur, e.g. cyclomethicone or phospholipids - A61P 23/02: Local anaesthetics - A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D) - A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS ## 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 ### Claim at position 1 1-8. (canceled) ### Claim 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 μm to 50 μm in size. ### Claim 10 (depends on 9) 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. ### Claim 11 (depends on 9) 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. ### Claim 12 (depends on 9) 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. ### Claim 13 (depends on 9) 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. ### Claim 14 (depends on 9) 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. ### Claim 15 (depends on 14) 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. ### Claim 16 (depends on 9) The method of claim 9, wherein an administration route of the multivesicular liposome is local injection administration.