Polymerizable siloxane-quaternary amine copolymers

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The present invention relates to polymeric compositions useful in the manufacture of biocompatible medical devices. More particularly, the present invention relates to certain cationic monomers capable of polymerization to form polymeric compositions having desirable physical characteristics useful in the manufacture of ophthalmic devices. Such properties include the ability to extract the polymerized medical devices with water. This avoids the use of organic solvents as is typical in the art. The polymer compositions comprise polymerized silicon containing monomers end-capped with ethylenically unsaturated cationic hydrophilic groups.

Various articles, including biomedical devices, are formed of organosilicon-containing materials. One class of organosilicon materials useful for biomedical devices, such as soft contact lenses, is silicon-containing hydrogel materials. A hydrogel is a hydrated, cross linked polymeric system that contains water in an equilibrium state. Hydrogel contact lenses offer relatively high oxygen permeability as well as desirable biocompatibility and comfort. The inclusion of a silicon-containing material in the hydrogel formulation generally provides higher oxygen permeability since silicon based materials have higher oxygen permeability than water.

Another class of organosilicon materials is rigid, gas permeable materials used for hard contact lenses. Such materials are generally formed of silicon or fluorosilicon copolymers. These materials are oxygen permeable, and more rigid than the materials used for soft contact lenses. Organosilicon-containing materials useful for biomedical devices, including contact lenses, are disclosed in the following U.S. patents: U.S. Pat. No. 4,686,267 (Ellis et al.); U.S. Pat. No. 5,034,461 (Lai et al.); and U.S. Pat. No. 5,070,215 (Bambury et al.).

In addition, traditional siloxane-type monomers are hydrophobic and lenses made with them frequently require additional treatment to provide a hydrophilic surface. Although not wishing to be bound by a particular theory, the inventors believe that providing a charged siloxane-type monomer such as the quaternary siloxane-type monomers disclosed herein results in a hydrophilic siloxane-type monomer. It is believed that the hydrophilic quaternary groups interact with the electronegative portion of the polar water molecule.

Soft contact lens materials are made by polymerizing and crosslinking hydrophilic monomers such as 2-hydroxyethylmethyacrylate, N-vinyl-2-pyrrolidone, methacrylic acid and combinations thereof. The polymers produced by polymerizing these hydrophilic monomers exhibit significant hydrophilic character themselves and are capable of absorbing a significant amount of water in their polymeric matrices. Due to their ability to absorb water, these polymers are often referred to as “hydrogels”. These hydrogels are optically clear and, due to their high levels of water of hydration, are particularly useful materials for making soft contact lenses. Siloxane-type monomers are well known to be poorly soluble in water as well as hydrophilic solvents and monomers and are therefore difficult to copolymerize and process using standard hydrogel techniques. Therefore, there is a need for new siloxane-type monomers that have improved solubility in the materials, specifically the diluents, used to make hydrogel lenses. Further there is a need for monomers that result in a polymerized medical device that is extractable in water instead of the organic solvents used in the prior art.

The term “monomer” and like terms as used herein denote relatively low molecular weight compounds that are polymerizable by, for example, free radical polymerization, as well as higher molecular weight compounds also referred to as “prepolymers”, “macromonomers”, and related terms.

The term “(meth)” as used herein denotes an optional methyl substituent. Accordingly, terms such as “(meth)acrylate” denotes either methacrylate or acrylate, and “(meth)acrylic acid” denotes either methacrylic acid or acrylic acid.

The present invention provides novel cationic organosilicon-containing monomers which are useful in articles such as biomedical devices including contact lenses.

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In a first aspect, the invention relates to monomers of formula (I):

wherein L can be the same or different and is selected from the group consisting of a bond, urethanes, carbonates, carbamates, carboxyl ureidos, sulfonyls, a straight or branched C1-C30 alkyl group, a C1-C30 fluoroalkyl group, a C1-C20 ester-containing group, an alkyl ether, cycloalkyl ether, cycloalkenyl ether, aryl ether, arylalkyl ether, a polyether containing group, an ureido group, an amide group, an amine group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C3-C30 cycloalkylalkyl group, a substituted or unsubstituted C3-C30 cycloalkenyl group, a substituted or unsubstituted C5-C30 aryl group, a substituted or unsubstituted C5-C30 arylalkyl group, a substituted or unsubstituted C5-C30 heteroaryl group, a substituted or unsubstituted C3-C30 heterocyclic ring, a substituted or unsubstituted C4-C30 heterocyclolalkyl group, a substituted or unsubstituted C6-C30 heteroarylalkyl group, a C5-C30 fluoroaryl group, or a hydroxyl substituted alkyl ether and combinations thereof.