Injectable sustained-release formulations for treatment of joint pain and inflammation
Inventors
Ugwu, Sydney • He, James • Fu, Zengli
Assignees
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Publication Number
US-12589102-B2
Publication Date
2026-03-31
Expiration Date
Abstract
Drug-loaded microspheres containing both a steroidal anti-inflammatory drug and a non-steroidal anti-inflammatory drug and injectable formulations containing the microspheres for sustained release of both drugs are disclosed. Methods of making such drug-loaded microspheres, formulations, and use of them for treating pains and inflammations, especially those caused by rheumatoid arthritis or osteoarthritis using such microspheres and formulations are also described.
Core Innovation
The invention relates to an injectable sustained-release formulation that comprises drug microspheres including methylprednisolone acetate (MPA) and celecoxib (CXB) encapsulated in poly(lactic-co-glycolic acid) copolymers (PLGA). The formulation specifies PLGA with a molecular weight in the range between 10 kD and 130 kD and a lactic acid:glycolic acid molar ratio between about 50:50 to about 75:25. The microspheres have a mean diameter between 40 μm and 70 μm and contain defined amounts of MPA and CXB by weight.
The sustained-release behavior is defined such that the drug microspheres release at least 30% of the MPA in the first week following parenteral administration to a patient. The remaining MPA is released over at least one month following parenteral administration. This provides a burst-to-sustained release profile for the steroidal anti-inflammatory drug within the injectable sustained-release formulation.
In addition, the microspheres are suspended in a diluent solution suitable for injection. The diluent solution is described as preferably comprising hyaluronic acid (HA). The invention further contemplates preparation of the microspheres by an S/O/W emulsion process with solvent extraction/evaporation followed by particle washing and particle drying, and then suspending the drug-loaded microspheres in the diluent solution.
Claims Coverage
The provided independent claim set includes one independent claim that defines an injectable sustained-release formulation with multiple inventive features, including dual-drug PLGA-encapsulated microspheres, specified polymer characteristics, specified drug loading and particle size, and a defined MPA release schedule.
Dual-drug PLGA-encapsulated microspheres for sustained release
Drug microspheres comprising both methylprednisolone acetate (MPA) and celecoxib (CXB) encapsulated in poly(lactic-co-glycolic acid) copolymers (PLGA), wherein the MPA comprises between 15% and 40% by weight of the drug microspheres and the CXB comprises between 15% to 40% by weight of the drug microspheres.
Specified PLGA copolymer characteristics
PLGA with a molecular weight in the range between 10 kD and 130 kD and a lactic acid:glycolic acid molar ratio between about 50:50 to about 75:25.
Specified microsphere size and injection suspension format
The drug microspheres have a mean diameter of between 40 μm and 70 μm, and the drug microspheres are suspended in a diluent solution.
Defined MPA burst and sustained release schedule
The drug microspheres release at least 30% of the MPA in the first week following parenteral administration to a patient and the remaining MPA is released over at least one month following the parenteral administration to the patient.
Across the independent claim, the core coverage is directed to a suspended injectable sustained-release formulation of PLGA-encapsulated microspheres carrying both MPA and CXB, with specified PLGA molecular weight and lactic acid:glycolic acid molar ratio, specified microsphere size and drug loading ranges, and a release profile requiring at least 30% MPA release in the first week followed by release of the remaining MPA over at least one month.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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