Drug-Loaded Microcapsules Hardening Stage Adsorption
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Solution Overview
Problem
There is a need for biocompatible, biodegradable echogenic microcapsules and nanocapsules with reproducible size range for both contrast imaging and drug delivery that offer high loading capabilities and acceptable echogenicity, which current methods fail to provide effectively.
Innovation Solution
The development of hardening stage and pre-hardening stage adsorption methods for producing echogenic drug-loaded polymer microcapsules and nanocapsules involves forming mixtures with volatile solvents, emulsifying, and hardening with a drug-containing solvent, resulting in higher drug loading capacities and stability, with at least 10% more drug loading compared to traditional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional drug loading methods are used for microcapsules, then the manufacturing process is simple, but the drug loading capacity is low
Solution Approach 1:
The patent introduces a pre-hardening stage where microcapsules are hardened before final drug loading. This preliminary hardening creates a stable structure that can subsequently accommodate higher drug loads without compromising structural integrity, thereby enabling higher drug loading capacity while maintaining a manageable manufacturing process
Solution Approach 2:
The patent employs parameter changes by controlling the hardening conditions (temperature, time, solvent removal rate) during the pre-hardening stage to optimize the microcapsule structure for subsequent drug loading. This allows the microcapsules to achieve optimal physical and chemical properties that maximize drug loading capacity
2Quantity of substance
If high drug loading is achieved, then therapeutic efficacy is improved, but echogenicity may be compromised
Solution Approach 1:
The patent applies local quality by ensuring uniform drug distribution within the microcapsule structure through controlled loading methods. This uniform distribution prevents aggregation and maintains the microcapsules' acoustic properties, thereby preserving echogenicity even at high drug loading levels
Solution Approach 2:
The patent utilizes porous microcapsule structures that allow drug incorporation while maintaining the acoustic impedance mismatch necessary for echogenicity. The porous structure provides high surface area for drug loading while preserving the structural integrity needed for ultrasound contrast
3Measurement precision
If microcapsules are produced with reproducible size range, then imaging precision is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs periodic action through controlled emulsification and solvent removal cycles that create consistent microcapsule sizes. The repeated cycles of emulsification, hardening, and size selection produce a narrow size distribution, improving size uniformity while keeping the manufacturing process systematic and controllable
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
These methods achieve unexpectedly high drug loading capabilities and maintain acceptable echogenicity, enabling efficient drug delivery and imaging while allowing for regulated stability through polymer component selection, with drug-loaded microcapsules showing enhanced loading efficiency and stability.
Implementation Method 1
forming a first mixture comprising a solution of at least one polymer in at least one volatile non-polar solvent
Implementation Method 2
emulsifying, and hardening with a drug-containing solvent
Implementation Method 3
hardening stage and pre-hardening stage adsorption methods for producing echogenic drug-loaded polymer microcapsules
Data Source
AI summary
This invention provides an improvement to methods of drug loading of ultrasound contrast agents. Echogenic drug-loaded polymer microcapsules, nanocapsules, or mixtures thereof produced by the method of the invention wherein the echogenic drug-loaded polymer microcapsules, nanocapsules, or mixtures thereof contain at least 10% more of a drug as compared to (1) echogenic drug-loaded polymer microcapsules, nanocapsules, or mixtures thereof prepared by adding drug prior to emulsifying or (2) echogenic drug-loaded polymer microcapsules, nanocapsules, or mixtures thereof prepared by adding drug to lyophilized polymer microcapsules, nanocapsules, or mixtures thereof.