Patent Application
20080027461
Illustrative, non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which the same reference number is used to designate the same or similar components in different figures, and in which:
A simplified IOL 50 is illustrated in body 12. It is to be appreciated that injector 10 may be provided with any suitable IOL loading apparatus such a hinged door in the side of the injector body. The proximal end of the body includes a finger hold 24 and plunger 15 includes a finger press 32 at the proximal end thereof for pressing and advancing the plunger through lumen 13 in the manner of a syringe. A plunger tip 17 is provided at the distal end of the plunger for engaging and pushing IOL 50 through and out of tip 16 of the injector body 12.
According to aspects of the present invention, a plunger having a shaft comprising a polymeric material that has a flexural modulus of at least 600 thousand pounds per square inch (kpsi) is provided. In some embodiments, the flexural modulus is greater than 750 thousand psi, and in some embodiments greater than 1 million psi (Mpsi).
Provided below are examples of families of polymeric materials that provide flexural moduluses of at least 600 kpsi It is to be appreciated that a given material may provide a suitable modulus either “neat” (i.e., without fillers), filled (e.g., with glass fiber or glass beed or carbon fiber or mineral fillers at a suitable percentage), or including copolymers of multiple polymers. The examples of families of materials include—
Acrylonitrile Butadiene Stryene (ABS)
Acetal
Acrylic
Polyketone
Polyetheretherketone (PEEK)
Liquid Crystal Polymer (LCP)
Nylon—various permutations (46,6,66/6,66,610,612,11,12),
Polyamide
Polyimide
Polyarylamide
Polycarbonate
Polybutylene Terephthalate (PBT)
Polyethylene Terephthalate (PET)
Polyester
Polyetherimide
Polyethersulfone (PES)
Polyimide, Polyphenylene Ether
Polyphenylene, Sulfide (PPS)
Polyphthalamide (PPA)
Polypropylene
Polystyrene
Polysulfone
Polyphenylsulfone
Polyarylsulfone
Polyvynalchloride
Polyphenyloxide (PPO)
SAN
In some embodiments, it is desirable that the plunger 15 be properly aligned and rotationally fixed within the lumen 13 so as to further ensure proper engagement of the IOL 50 with plunger tip 17 and to reduce the likelihood of rotation of a lens. Plunger alignment and rotational fixing can be achieved, for example, by forming the body 12 and proximal end 15a of the plunger in a non-circular (e.g., oval) cross-sectional shape.
Additionally, to assist in controlling forward movement of the plunger within the body, a plunger may use one or more rubber O-rings or other molded alignment features 20a, 20b which provide friction between the plunger and inside wall of the body.
It is to be understood that aspects of the invention are directed to the plunger shaft. In embodiments of the invention that are according to such aspects, other parts of the injector (e.g., the plunger tip, the cross-sectional shape of the injector body, the IOL loading area, the injector distal tip, etc.) may be of any desired configuration.
It is to be appreciated that a soft tip (e.g., comprising silicone) may be provided as the plunger tip, for example, to protect an IOL from the material comprising the shaft. Such a configuration is particularly advantageous, in the embodiments where the high flexural modulus material comprising the shaft has a propensity to damage the lens (e.g., due to jagged edges perhaps caused by a filler). A soft tip may be applied, for example, by dip coating the distal end of the plunger in a soft material or by forming the soft material such that it has a sleeve in the proximal end of the tip, where the distal end of the plunger can be received. For example, a soft tip as described in U.S. Pat. No. 5,735,858, to Makker may be used. A tip (regardless of whether it is soft or integrated with the plunger shaft) may be selected to have any suitable shape. For example, a tip can have forked shape (as illustrated in
One example of a material that has been found to be suitable for formation of a plunger shaft is Polyphthalamide (PPA) having a 40% mineral fill (e.g., calcium carbonate fill). PPA having a 40% fill was measured to have a flexural modulus of 1.1 Mpsi using ASTM D790 or 1.0 at 23° C. using ISO 178. For example, PPA is available from Solvay Plastics of Brussels, Belgium.
In addition to the suitable flexural modulus provided by PPA, a desirable characteristic of PPA is that, upon curing, a resultant plunger is free of sharp edges that may cause tearing of an IOL. Also it was found that PPA provides advantageous moldability characteristics that permit small features to be manufactured. Accordingly, in some embodiments, the entire plunger (including the plunger tip) is made of PPA (i.e., the tip is made of the same material as the shaft and may be integrated therewith). Accordingly, in such embodiments a plunger may be used without a soft tip. For example, PPA has been demonstrated to fill a mold of a forked tip.
Another example of a material that has been found to be suitable for formation of a plunger shaft is Polybutylene Terephthalate (PBT) having a 30% glass fill. PBT having a 30% glass fill was measured to have a flexural modulus of 1.1 Mpsi using ASTM D790. For example, such PBT is available from General Electric Corporation of Fairfield, Conn. under the tradename, Valox®. Valox having a glass fill, while having a suitable flexural modulus was found to have sharp edges that may cause damage to IOLs. Accordingly, it may be desirable to add a soft tip as described above, over the distal end of the shaft. For example, the glass fill may comprise glass fiber particles having a cylindrical shape with an average length of approximately 3 mm.
Yet another example of a material that has been found suitable for formation of a plunger shaft is Polyarylamide (PAA) having a 50% glass fill (the fill particles having a diameter of approximately 10 to 15 microns and a length of approximately 1.6 mm). For example, such PAA is available from Solvay Plastics under the tradename IXEF 1022. It was found that PPA provides advantageous moldability characteristics that permit small features to be manufactured. For example, PAA has been demonstrated to fill a mold of a forked tip. Additionally, PAA forms a stratified structure upon molding such that the glass fill is covered by a skin of polymer material which reduces the amount of glass fiber on the surface of a molded part.
In some embodiments, the entire plunger (including the plunger tip) is made of PAA (i.e., the tip is made of the same material as the shaft and may be integrated therewith). In such embodiments a plunger may be used without a soft tip.
Other examples of materials having suitable flexural moduluses are PBT having a 30% glass fill, available from General Electric, under the name Valox 420 HP; LCP having a 15% mineral fill, available from Ticona division of Celanese Inc. of Auburn Hills, Mich., under the name Vectra A515; LCP having a 30% mineral fill, available from Ticona, under the name Vectra E530i; LCP having a 30% mineral fill, available from Dupont Inc, under the name Zenite 6330 NC 010.
Having thus described the inventive concepts and a number of exemplary embodiments, it will be apparent to those skilled in the art that the invention may be implemented in various ways, and that modifications and improvements will readily occur to such persons. Thus, the embodiments are not intended to be limiting and presented by way of example only. The invention is limited only as required by the following claims and equivalents thereto.
This application claims the benefit of Provisional Patent Application No. 60/833,203 filed Jul. 25, 2006.
| Number | Date | Country | |
|---|---|---|---|
| 60833203 | Jul 2006 | US |
