Aggregating microparticles for medical therapy
Inventors
Yu, Yun • Kays, Joshua • Yang, Ming • Cleland, Jeffrey L.
Assignees
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Publication Number
US-11564890-B2
Publication Date
2023-01-31
Expiration Date
Abstract
The present invention is a surface treated drug-loaded solid (e.g., non-porous) microparticle that aggregates in vivo to form a consolidated larger particle for medical therapy. In one embodiment, the particles are used for ocular therapy. Processes for producing the surface treated microparticle and injectable formulations which include the surface treated microparticle are also provided. When used in the eye, long-term consistent intraocular delivery can be achieved without disrupting vision and minimizing undesirable inflammatory responses.
Core Innovation
The invention provides surface-modified aggregating microparticles comprising at least one biodegradable polymer, a surfactant, and a therapeutic agent that is not covalently bound to the biodegradable polymer. The microparticles have a mean diameter between 10 µm and 60 µm and contain from about 0.001 percent to about 1 percent surfactant. The microparticles are surface-modified so that the surface contains less surfactant than a microparticle prior to the surface modification, and the surface is modified at a temperature less than about 18° C.
In vivo, the microparticles aggregate to form at least one pellet of at least 500 µm. The formed pellet is capable of sustained drug delivery in vivo for at least one month. This pellet-forming aggregation behavior is a required functional outcome of the claimed microparticle composition and the specified surface-modified characteristics.
A central aspect is tuning drug-release kinetics by controlling how the therapeutic agent migrates from the particle matrix and how the microparticles consolidate after surface modification. The document links release behavior to drug solubility in the particle matrix through polymer composition, hydrophilic/hydrophobic balance, functional groups, and additives, and further relates release to exposed surface area and polymer surface morphology such as porosity and channels versus minimized exposed area.
The disclosed system remains injectable while aggregating in vivo to form an external pellet located outside the visual axis for ocular therapy. The concept supports sustained intraocular drug delivery and is associated with reduced inflammatory or visual side effects, as stated in the provided document summary.
Claims Coverage
The independent claim is clm-00001. It covers surface-modified aggregating microparticles with specified particle sizing, surfactant content and reduction, and a surface-modification temperature constraint, together with an in vivo aggregation outcome requiring pellet formation of at least 500 µm and sustained drug delivery in vivo for at least one month.
Surface-modified aggregating microparticles with reduced surfactant surface
Surface-modified aggregating microparticles comprising at least one biodegradable polymer, a surfactant, and a therapeutic agent not covalently bound to the biodegradable polymer, wherein the microparticles have a mean diameter between 10 µm and 60 µm; contain from about 0.001 percent to about 1 percent surfactant; have been surface-modified to contain less surfactant than a microparticle prior to the surface modification; and the surface has been modified at a temperature less than about 18° C.
In vivo pellet aggregation for sustained drug delivery
Microparticles that aggregate in vivo to form at least one pellet of at least 500 µm in vivo capable of sustained drug delivery in vivo for at least one month.
Overall, claim coverage centers on the combination of surface-modified solid aggregating microparticles with controlled surfactant content reduction and a surface-modification temperature below about 18° C, together with an in vivo aggregation requirement to form pellets of at least 500 µm that provide sustained drug delivery in vivo for at least one month.
Stated Advantages
Sustained in vivo drug delivery associated with injectable, aggregating microparticle behavior.
Reduced inflammatory or visual side effects, as stated in the provided document summary.
Documented Applications
Ocular therapy involving intraocular treatment with in vivo aggregation forming a pellet located outside the visual axis.
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