Low-Temperature Melt Extrusion for Intraocular Cyclic Lipid Implants
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Solution Overview
Problem
Existing methods for making intraocular implants, particularly those using heat to melt polymers, can lead to degradation of therapeutic agents, formation of undesirable end products, and presence of polymorphic forms, which can reduce efficacy and cause side effects such as ocular hyperemia.
Innovation Solution
A low-temperature melt extrusion process is employed to create intraocular implants using a combination of a prostaglandin analog and biodegradable polymers like poly(lactide-co-glycolide) with a second polymer acting as a cosolvent, ensuring the therapeutic agent remains potent and is not present in crystalline form, thereby avoiding polymorphic issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the therapeutic agent-polymer mixture is heated to the melt temperature of the polymer (90°C to 115°C) to ensure even distribution and form a solid implant, then the homogeneity of the therapeutic agent in the polymeric matrix is improved, but the therapeutic agent may degrade, lose potency, or form undesirable degradation products and aggregates
Solution Approach 1:
The patent applies parameter changes by modifying the temperature parameter from the conventional 90-115°C range to a lower range of 50-80°C. This temperature reduction prevents degradation of heat-sensitive therapeutic agents while still enabling the polymer to achieve adequate流动性 for homogeneous mixing and extrusion. The lower temperature parameter maintains the homogeneity benefit without triggering the harmful degradation effects.
Solution Approach 2:
The patent introduces a cosolvent as an intermediary substance to facilitate the mixing and extrusion process at lower temperatures. The cosolvent acts as a mediator that enables the polymer to flow and distribute the therapeutic agent uniformly without requiring high temperatures that would cause degradation. This intermediary substance allows the process to proceed at temperatures below the polymer's typical melt point.
2Ease of manufacture
If the crystalline therapeutic agent is melted along with the polymeric matrix or mixed without melting, then the implant can be formed, but the therapeutic agent may recrystallize in different polymorphic forms with different stabilities, solubilities, and therapeutic efficacies
Solution Approach 1:
The patent applies parameter changes by using temperature (50-80°C) that is sufficient to melt the polymer matrix but deliberately kept below the melting point of the crystalline therapeutic agent. This temperature parameter control prevents the therapeutic agent from melting and subsequently recrystallizing in unwanted polymorphic forms, while still allowing the polymer to flow and form the implant structure.
Solution Approach 2:
The cosolvent serves as an intermediary that allows the polymer to become flowable at lower temperatures without requiring the therapeutic agent to melt. This enables the implant formation process to proceed while keeping the therapeutic agent in its original crystalline form, thereby avoiding polymorphic transformation issues.
3Ease of operation
If heating is used to melt the polymer for extrusion, then the polymer becomes flowable and can be extruded into desired implant shapes, but heat-sensitive therapeutic agents lose potency and therapeutic efficacy is reduced
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperatures (90-115°C) to a lower range (50-80°C). This parameter modification reduces the thermal energy input sufficient to maintain polymer flowability for extrusion while staying below the threshold that causes degradation of heat-sensitive therapeutic agents, thereby preserving their potency.
Solution Approach 2:
The cosolvent acts as an intermediary substance that enhances polymer flowability at lower temperatures. By introducing this intermediary, the system achieves the necessary rheological properties for extrusion without relying on high thermal energy that would compromise the stability and potency of heat-sensitive therapeutic agents.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process results in sustained release implants that maintain therapeutic potency for extended periods, reduce side effects, and effectively deliver cyclic lipid therapeutic agents to the eye, providing prolonged treatment of ocular conditions like glaucoma without daily administration.
Implementation Method 1
The mixture is then heated to a temperature between about 50°C and about 80°C, followed by extruding the heated mixture
Implementation Method 2
followed by extruding the heated mixture to thereby make an implant suitable for intraocular use
Data Source
Figure 1~2
Figure 3
AI summary
Biocompatible implants comprising a cyclic lipid therapeutic agent are made using a low temperature melt extrusion process. The implants are suitable for intraocular use to treat an ocular condition.