Post-charging of zeolite doped plastics with antimicrobial metal ions
Inventors
Crudden, Joseph J. • Johns, Derrick
Assignees
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Publication Number
US-9492584-B2
Publication Date
2016-11-15
Expiration Date
Abstract
Methods of post-loading ceramic particles with antimicrobial metal cations are disclosed. In certain embodiments, the post-loaded particles are zeolites, wherein the zeolites have been incorporated into a resin and the combination is used as an implantable device. In certain embodiments, the polymer is a thermoplastic polymer such as polyaryletheretherketone (PEEK). In certain embodiments, the source of antimicrobial activity includes ion-exchangeable cations contained in a zeolite. In certain embodiments, disclosed are methods of imparting antimicrobial activity to devices by controlling the delivery of certain cations through ion-exchange via a zeolite incorporated in the device.
Core Innovation
The disclosed invention provides antimicrobial activity in a thermoplastic polymer implant by using uncharged A-type zeolite particles that are later charged with one or more antimicrobial metal cations. The A-type zeolite particles have a three dimensional skeletal structure represented by the formula XM2/nO·Al2O3·YSiO2·Z H2O, where M represents an ion-exchangeable ion and Z represents the number of water of crystallization, and are incorporated into a thermoplastic polymer.
After incorporation into the thermoplastic polymer, the charged zeolite releases metal ions via ion-exchange when the polymer is implanted in the body of a patient. The invention establishes the rate of release of the one or more metal ions from the zeolite particles in the thermoplastic polymer so that an antimicrobially effective amount is achieved upon implantation and contact with bodily tissue or fluid.
The disclosure includes forming a thermoplastic implant with at least some of the A-type zeolite particles present at the implant surface so the surface contacts body tissue or fluid when implanted. The invention further includes an infusion solution comprising antimicrobial metal cation salt and nitric acid, and exposes the implant to this infusion solution to load the zeolite particles with the antimicrobial metal cation and etch the implant surface with the acid.
The disclosure specifies antimicrobial metal cations associated with the zeolite, including silver (Ag+), zinc (Zn2+), and copper (Cu+, Cu2+). It also contemplates controlled cation loading relative to the zeolite ion-exchange capacity and mentions retained radiopacity.
Claims Coverage
The partial content includes three independent methods with a shared theme: incorporating or forming uncharged A-type zeolite particles in a thermoplastic polymer, charging the zeolites with antimicrobial metal cations, and establishing a metal-ion release rate so antimicrobial activity is achieved via ion-exchange after implantation. Each independent claim contains multiple inventive elements centered on zeolite structure, charging/loading with antimicrobial cations, and controlling ion release in the thermoplastic polymer for in-body antimicrobial effect.
Post-charging antimicrobial A-type zeolite particles in a thermoplastic polymer with established ion-release rate
Incorporating uncharged A-type zeolite particles having a three dimensional skeletal structure XM2/nO·Al2O3·YSiO2·Z H2O into a thermoplastic polymer, thereafter charging said zeolite particles with one or more metal cations, and establishing the rate of release of said one or more metal ions from said zeolite particles in the thermoplastic polymer so that antimicrobial activity is achieved when implanted and contacts bodily tissue or fluid to release said one or more metal cations from said thermoplastic polymer via ion-exchange.
Imparting antimicrobial activity to a device by controlling release of antimicrobial cations through ion-exchange
Imparting antimicrobial activity to a device by controlling the release of antimicrobial cations from said device through ion-exchange by incorporating A-type zeolite particles having the three dimensional skeletal structure XM2/nO·Al2O3·YSiO2·Z H2O into a thermoplastic polymer, subsequently charging said zeolite particles with one or more metal cations, and establishing the rate of release of said one or more metal ions from said zeolite particles in the thermoplastic polymer, wherein antimicrobial activity is achieved when implanted and contacts bodily tissue or fluid to release said one or more metal cations via ion-exchange.
Making an implant with zeolite at the surface, loaded via infusion solution with nitric acid and established ion-release rate
Forming an implant having a surface with at least some uncharged A-type zeolite particles having the three dimensional skeletal structure XM2/nO·Al2O3·YSiO2·Z H2O such that the surface contacts body tissue or fluid when implanted, providing an infusion solution comprising antimicrobial metal cation salt and nitric acid, exposing the implant to said infusion solution to load the zeolite particles with said antimicrobial metal cation and to etch the implant surface with said acid, and establishing the rate of release of said one or more metal ions from said zeolite particles in the thermoplastic polymer so zeolite particles at the implant surface are capable of releasing said metal cations in an antimicrobially effective amount when the surface contacts said body tissue or fluid.
Across the independent claims, antimicrobial performance is enabled by A-type zeolite particles with a defined skeletal formula incorporated in a thermoplastic polymer, including at an implant surface, charged with antimicrobial metal cations, and with an established rate of metal-ion release such that antimicrobial activity occurs after implantation through ion-exchange with bodily tissue or fluid.
Stated Advantages
Achieves antimicrobial activity when the thermoplastic polymer is implanted in the body of a patient and contacts bodily tissue or fluid to release metal cations via ion-exchange.
Releases metal cations in an antimicrobially effective amount when the implant surface contacts body tissue or fluid.
Retained radiopacity is mentioned in the disclosed summary.
Documented Applications
Implantable medical devices, including thermoplastic polymer implants having zeolite particles at an implant surface that contacts bodily tissue or fluid.
Wound dressings.
Self-sterilizing fibers/face masks.
Other consumer/medical surfaces are mentioned in the disclosed summary.
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