PVA-HA Microspheres for Stable Drug Loading
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Solution Overview
Problem
Current microsphere preparation methods face challenges such as complex and unstable production processes, limited control over particle size, low drug loading efficiency, unsatisfactory sustained release performance, and toxicity issues, particularly for temperature-sensitive drugs and large-scale production.
Innovation Solution
A method involving a mixture of liquid paraffin and sorbitan fatty acid ester as the oil phase, with an aqueous solution of PVA and HA particles, using controlled pre-reaction with glutaraldehyde and acidic conditions to form cross-linked microspheres with adjustable sizes and enhanced drug encapsulation, employing a specific mass ratio of PVA to HA for improved encapsulation efficiency and sustained release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional microsphere preparation methods (reverse suspension polymerization, electrostatic spraying, emulsification and cross-linking, phase separation, solvent evaporation, single emulsion) are used, then microspheres can be produced, but the production process becomes complex and unstable, with limited control over particle size and low drug loading efficiency
Solution Approach 1:
The patent applies preliminary action by pre-mixing the aqueous phase containing PVA and HA particles before adding to the oil phase. This pre-mixing step ensures uniform distribution of components and stabilizes the emulsion formation, leading to more consistent microsphere production with controlled particle sizes and improved production process stability.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the mass ratio of PVA to HA particles and controlling the addition rate of the aqueous phase to the oil phase. These parameter optimizations enable precise control over microsphere size, composition, and formation stability, resolving the complexity-stability contradiction.
2Manufacturing precision
If conventional methods are used, then microspheres can be prepared, but particle size control is limited and drug loading efficiency is low
Solution Approach 1:
The patent applies local quality by incorporating HA particles specifically into the aqueous phase that will form the microsphere core, creating localized regions with different properties. This results in microspheres with controlled particle sizes and enhanced drug loading capacity in specific regions, improving both precision and productivity.
Solution Approach 2:
The patent uses composite materials by combining PVA polymer with HA particles in a specific mass ratio within the microsphere structure. This composite approach enables precise particle size control and high drug loading efficiency, as the HA particles provide both structural framework and drug carrying capacity.
3Duration of action of stationary object
If conventional methods are used, then microspheres can be produced, but sustained release performance is unsatisfactory and toxicity issues arise
Solution Approach 1:
The patent applies porous materials by using HA particles with inherent porous structures within the microsphere. These porous structures provide controlled release pathways for drugs, extending the duration of action while maintaining biocompatibility and reducing toxicity, as HA is a biodegradable material with good biocompatibility.
Solution Approach 2:
The patent utilizes parameter changes by optimizing the mass ratio of PVA to HA particles and controlling the cross-linking conditions. These parameter optimizations enhance sustained release performance while maintaining material biocompatibility and minimizing toxicity, resolving the contradiction between duration of action and harmful factors.
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
The method achieves high drug loading, stable and controlled release, biocompatibility, and adjustable particle sizes, improving production efficiency and industrial applicability with enhanced embolization and radiopaque effects.
Implementation Method 1
adding glutaraldehyde as cross-linker to the PVA; the PVA in the aqueous phase is cross-linked by the added water-soluble initiator to form a cross-linked product
Implementation Method 2
the pH of the reaction mixture was adjusted using an alkaline solution to allow the in-situ deposition of hydroxyapaptite (HA) after adding glutaraldehyde as cross-linker to the PVA
Implementation Method 3
the microspheres block blood vessel in the target tumor blood vessels and block the source of nutrition for tumor cells
Implementation Method 4
the microspheres can carry drugs, and the released drug can inhibit tumor growth
Data Source
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AI summary
The present invention provides a novel microsphere capable of drug-loading and a preparation method thereof. The preparation method comprises pre-mixing an aqueous solution of polyvinyl alcohol and hydroxyapatite particles, then adding concentrated hydrochloric acid as a catalyst, and then adding the crosslinking agent glutaraldehyde to obtain the reaction liquid, after 3 seconds-30 seconds of pre-reaction, before the pre-reaction liquid is coagulated, the pre-reaction liquid is added dropwise to the mixture oil phase including liquid paraffin and sorbitan fatty acid ester, and the reaction is continued for at least 3 hours with stirring in an oil bath at 50°C-60°C, and then the reacted mixture is filtered, washed, and dried to obtain microspheres capable of drug-loading. The method of the present invention is conducive to mass production, and the microspheres capable of drug-loading prepared by the method have higher drug loading and encapsulation efficiency, with a good sustained release performance, and the hydroxyapatite particles are embedded in the poly(vinyl alcohol) after the polymerization reaction, makes the microspheres capable of drug-loading have a certain radiopaque function.