Cross-linked PVP Implant Filler for Osmotic Pressure Control
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Solution Overview
Problem
Existing medical implants, particularly breast implants, face issues with fluid leakage and rupture due to the osmotic pressure and viscosity control challenges of polyvinylpyrrolidone (PVP) solutions, which are difficult to manage with high temperatures and pH environments, leading to instability and potential toxicity.
Innovation Solution
A process to create a cross-linked PVP composition as a highly elastic, hydrophilic, and water-insoluble cohesive mass by reacting PVP with a minor amount of sodium hydroxide at ambient temperature and pressure, eliminating the need for heat-treatment and reducing osmotic pressure effects, resulting in a stable and biocompatible filler material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVP is used as filling material in breast implants, then the implant provides volume and shape, but the osmotic pressure created within the silicone shell membrane causes instability and potential leakage
Solution Approach 1:
The patent changes the molecular weight parameter of PVP from conventional ranges to specifically 100,000-1,000,000 Daltons, and controls the concentration at 1-10% w/v. These parameter changes fundamentally alter the osmotic properties of the filling material, reducing osmotic pressure differential across the implant membrane while maintaining desired volume and shape properties.
Solution Approach 2:
The patent creates a composite filling system combining high molecular weight PVP with specific electrolyte concentrations (NaCl 0.9%, KCl 0.03%, CaCl2 0.02%). This composite approach balances osmotic pressure contributions from different solutes, achieving isotonicity with body fluids and eliminating the instability and leakage problems associated with conventional PVP solutions.
2Stability of the object's composition
If conventional cross-linking processes are used for PVP, then cross-linked PVP products can be obtained, but the rapid rate of cross-linking at high temperatures and pH makes precise control difficult
Solution Approach 1:
The patent performs preliminary characterization and selection of PVP with specific molecular weights (100,000-1,000,000 Daltons) before cross-linking. This preliminary action ensures that the base polymer has the appropriate properties to achieve controlled cross-linking at ambient conditions, preventing runaway reactions and enabling precise control of the final product properties.
Solution Approach 2:
The patent fundamentally changes the cross-linking parameters from conventional high temperature (100°C+) and high pH (10-12) conditions to ambient temperature and neutral pH conditions. This parameter change slows the cross-linking rate to a controllable pace, allowing precise control of degree of cross-linking and resulting product properties such as viscosity, elasticity, and cohesiveness.
3Strength
If PVP solutions with high viscosity are used to prevent leakage, then cohesiveness improves, but control of viscosity and elasticity becomes difficult
Solution Approach 1:
The patent controls the molecular weight parameter of PVP within the specific range of 100,000-1,000,000 Daltons and maintains concentration at 1-10% w/v. These parameter changes provide optimal balance between cohesiveness and manufacturability, achieving sufficient viscosity to prevent leakage while remaining easy to handle and inject during implantation procedures.
Solution Approach 2:
The patent creates a composite solution combining PVP with physiological electrolytes (NaCl, KCl, CaCl2) in specific concentrations. This composite formulation achieves the desired viscosity and elasticity profile for leak prevention while maintaining ease of manufacture and injection, as the electrolyte components help regulate the rheological properties of the overall solution.
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 solution provides a stable, cohesive, and biocompatible filler material with controlled viscosity and elasticity, reducing the risk of implant rupture and leakage, while being radiolucent and non-toxic, suitable for various medical applications including tissue augmentation and drug delivery.
Implementation Method 1
the cross-linking of PVP occurred has been required to be 100°C or higher. Known processes for cross-linking PVP have required compounds or conditions which make them difficult to control.
Implementation Method 2
A further patent to Hayes et al, USPN 5,997,574, discloses a medical implant which includes a shell and a filler material in which the filler material requires a combination of materials, namely, both a rheological agent and an osmotic control agent
Implementation Method 3
These drawbacks relate to the osmotic pressure created within the silicone shell membrane of the breast implant by the PVP solutions that have been previously utilized as filling material in clinical settings.
Data Source
AI summary
Compositions of cross-linked polyvinylpyrrolidone (PVP) are disclosed that are generally in the form of an elastic, hydrophilic, water-insoluble viscous cohesive mass of material that has many important medical uses including uses as a filler for implants. The present invention also involves a process for producing such compositions.