Redox processes for contact lens modification

Abstract

Medical devices having a wettable, biocompatible surface are described herein. Processes for producing such devices are also described.

What is claimed is: 
     
         1 . A process for modifying the surface of a silicon-containing polymer, the process comprising the steps of:
 forming a reaction mixture comprising the silicon-containing polymer, a polymerization monomer, a free radical initiator system and a solvent system, the polymerization monomer comprising a zwitterionic monomer and the free radical initiator system comprising a peroxide in the presence of a metal ion; and   polymerizing the polymerization monomer in the reaction mixture to form a surface modification polymer on the surface of the silicon-containing polymer, wherein the silicon-containing polymer does not undergo a plasma treatment and is not imbibed with an initiator or monomer.   
     
     
         2 . The process of  claim 1  wherein the peroxide is selected from the group consisting of benzoyl peroxide, lauroyl peroxide, hydrogen peroxide, dicumyl peroxide, tert-butyl hydroperoxide, tert-butyl peroxide, cumene hydroperoxide, cyclohexanone peroxide, dicumyl peroxide, lauroyl peroxide, and 2,4-pentanedione peroxide. 
     
     
         3 . The process of  claim 1  wherein the metal ion is selected from Fe 2+ , Cr 2+ , V 2+ , Ti 3+ , Co 2+ , and Cu + . 
     
     
         4 . The process of  claim 2  wherein the persulfate is selected from potassium persulfate, sodium persulfate, and ammonium persulfate. 
     
     
         5 . The process of  claim 1  wherein the silicon-containing polymer contains at least 10 wt. % silicon. 
     
     
         6 . The invention of  claim 1  wherein the surface modification polymer comprises a carboxyammonium polymer or a sulfoammonium polymer. 
     
     
         7 . The invention of  claim 1  wherein the surface modification polymer comprises a zwitterionic polymer. 
     
     
         8 . The invention of  claim 1  wherein the surface modification polymer comprises a carboxybetaine polymer or a sulfobetaine polymer. 
     
     
         9 . The invention of  claim 1  wherein the surface modification polymer comprises repeat units corresponding to Formula 1 
       
         
           
           
               
               
           
         
         wherein 
         X 1  and X 2  are independently hydrogen, hydrocarbyl, substituted hydrocarbyl, heterocyclo, or substituted carbonyl, provided, however, X 1  and X 2  are not each selected from the group consisting of aryl, heteroaryl, and heterosubstituted carbonyl, 
         X 3  is hydrogen, alkyl or substituted alkyl, 
         X 4  is —OX 40 , —NX 41 X 42 , —N + X 41 X 42 X 43 , —SX 40 , aryl, heteroaryl or acyl, 
         X 40  is hydrogen, hydrocarbyl, substituted hydrocarbyl, heterocyclo or acyl, and 
         X 41 , X 42  and X 43  are independently hydrogen, hydrocarbyl, substituted hydrocarbyl or heterocyclo. 
       
     
     
         10 . The invention of  claim 1  wherein the surface modification polymer comprises at least one repeat unit corresponding to Formula 2: 
       
         
           
           
               
               
           
         
         wherein
 X 3  is hydrogen, alkyl or substituted alkyl, and 
 X 4  is a pendant group comprising an oxylated alkylene moiety, a zwitterionic moiety, an anionic moiety, or a cationic moiety. 
 
       
     
     
         11 . The invention of  claim 1  wherein the surface modification polymer comprises repeat units corresponding to Formula 3: 
       
         
           
           
               
               
           
         
         wherein X 44  comprises an oxylated alkylene moiety, a zwitterionic moiety, an anionic moiety, or a cationic moiety. 
       
     
     
         12 . The invention of  claim 11  wherein X 44  is —OX 45 , —NHX 45 , or —SX 45 , and X 45  is a substituted hydrocarbyl or heterocyclo moiety comprising an oxylated alkylene moiety, a zwitterionic moiety, an anionic moiety, or a cationic moiety. 
     
     
         13 . The invention of  claim 11  wherein X 44  is —OX 45 , or —NX 45 X 46 , X 45  comprises an oxylated alkylene moiety corresponding to Formula POA-1 or a zwitterionic moiety corresponding to Formula ZI-1, ZI-2, ZI-3, ZI-4, ZI-5, ZI-6A, ZI-6B, or ZI-7 and X 46  is hydrogen, hydrocarbyl, substituted hydrocarbyl or heterocyclo: 
       
         
           
           
               
               
           
         
         wherein 
         T 1  and T 2  are independently oxygen, sulfur, NH or a bond, 
         T 3  is hydrocarbylene, substituted hydrocarbylene, ether, or oxylated alkylene, 
         Z 1  is a moiety comprising a quaternary nitrogen, phosphonium or sulfonium cationic group, and 
         * designates the point of covalent attachment, direct or indirect, of the zwitterion of Formula ZI-1 to the polymer backbone; 
       
       
         
           
           
               
               
           
         
         wherein * designates the point of covalent attachment of the zwitterion of Formula ZI-2 to the polymer backbone, T 3  is hydrocarbylene, substituted hydrocarbylene, or oxylated alkylene, and T 4 , T 5  and T 6  are independently hydrogen, hydrocarbyl, substituted hydrocarbyl or heterocyclo; 
       
       
         
           
           
               
               
           
         
         wherein 
         T 8  is a bond, hydrocarbylene, substituted hydrocarbylene, heterocyclo, or in combination with T 9  and T 10  and the nitrogen atom to which they are attached form a nitrogen-containing heteroaromatic ring, 
         T 9  and T 10  are independently hydrogen, hydrocarbyl, substituted hydrocarbyl or heterocyclo, or, T 9  and T 10 , in combination with T 8  and the nitrogen atom to which they are attached form a nitrogen-containing heteroaromatic ring, 
         T 11  is hydrocarbylene, substituted hydrocarbylene, ether, or oxylated alkylene, 
         Z 3  is carboxylate, phosphate, phosphonic, phosphonate, sulfate, sulfinic, or sulfonate, and 
         * designates the point of covalent attachment, direct or indirect, of the zwitterion of Formula ZI-3 to the polymer backbone; 
       
       
         
           
           
               
               
           
         
         wherein * designates the point of covalent attachment, direct or indirect, of the zwitterion of Formula ZI-4 to the polymer backbone; T 12  is a bond or —(CH 2 ) m — with m being 1 to 3; T 13  and T 14  are independently hydrogen, alkyl, or substituted alkyl; T 15  is optionally substituted alkylene, phenylene, ether, or oxylated alkylene; and Z 4  is carboxylate or sulfate; 
       
       
         
           
           
               
               
           
         
         wherein * designates the point of covalent attachment, direct or indirect, of the zwitterion of Formula ZI-5 to the polymer backbone; HET is a heterocycle containing a quaternary nitrogen atom, T 15  is optionally substituted alkylene, phenylene, ether, or oxylated alkylene; and Z 4  is carboxylate or sulfate; 
       
       
         
           
           
               
               
           
         
         wherein * designates the point of covalent attachment, direct or indirect, of the zwitterion of Formulae ZI-6A and ZI-6B to the polymer backbone; T 15  is optionally substituted alkylene, phenylene, ether, or oxylated alkylene; and Z 4  is carboxylate or sulfate; and 
       
       
         
           
           
               
               
           
         
         wherein T 4 , T 5  and T 6  are independently hydrogen, hydrocarbyl, substituted hydrocarbyl or heterocyclo; T 12  is a bond, hydrocarbylene, substituted hydrocarbylene, or heterocyclo, and * designates the point of covalent attachment, direct or indirect, of the zwitterion of Formula ZI-7 to the polymer backbone; 
       
       
         
           
           
               
               
           
         
         wherein a is 1-3, b is 1-8, each R 1  and R 2  is independently selected from the group consisting of hydrogen, halogen, and optionally substituted lower alkyl, R 3  is hydrocarbyl, substituted hydrocarbyl or heterocyclo, and * designates the point of attachment of the moieties corresponding to Formula POA-1 to the remainder of the pendant group and the backbone. 
       
     
     
         14 . The invention of  claim 11  wherein X 44  is —O(CH 2 ) 2 N + (CH 3 ) 2 (CH 2 ) n SO 3   − , —O(CH 2 ) 2 N + (CH 3 ) 2 (CH 2 ) n CO 2   − , —NH(CH 2 ) 3 N + (CH 3 ) 2 (CH 2 ) n CO 2   − , or —NH(CH 2 ) 3 N + (CH 3 ) 2 (CH 2 ) n SO 3   − , and n is 1-8. 
     
     
         15 . The invention of  claim 11  wherein X 44  is —NH(CH 2 ) m N(CH 2 ) n CH 3 (CH 2 ) p SO 3 , —NH(CH 2 ) m N(CH 2 ) n CH 3 (CH 2 ) p CO 2 , —NH(CH 2 ) m N + [(CH 2 ) n CH 3 ] 2 (CH 2 ) p SO 3 , —NH(CH 2 )N + [(CH 2 ) n CH 3 ] 2 (CH 2 ) p CO 2 , —NH(CH 2 ) m Ncyclo-(CH 2 ) p CO 2 , or —NH(CH 2 ) m Ncyclo-(CH 2 ) p SO 3 , Ncyclo- is a heterocyclic structure or a heterocyclic derivative containing at least one nitrogen atom, m is 1-8; n is 0-5; and p is 1-8. 
     
     
         16 . The invention of  claim 11  wherein X 44  is —O(CH 2 ) m N(CH 2 ) n CH 3 (CH 2 ) p SO 3 , —O(CH 2 ) m N(CH 2 ) n CH 3 (CH 2 ) p CO 2 , —O(CH 2 ) m N + [(CH 2 ) n CH 3 ] 2 (CH 2 ) p SO 3 , —O(CH 2 )N + [(CH 2 ) n CH 3 ] 2  (CH 2 ) p CO 2 , —O(CH 2 ) m Ncyclo-(CH 2 ) p CO 2 , or —O(CH 2 ) m Ncyclo-(CH 2 ) p SO 3 , Ncyclo- is a heterocyclic structure or a heterocyclic derivative containing at least one nitrogen atom, m is 1-8; n is 0-5; and p is 1-8. 
     
     
         17 . The invention of  claim 11  wherein the polymer contains repeat units corresponding to Formula 3 and X 44  is —O(CH 2 ) 2 N + (CH 3 ) 2 (CH 2 ) 3 SO 3 , —O(CH 2 ) 2 N + (CH 3 ) 2 (CH 2 ) 2 CO 2 , —NH(CH 2 ) 2 N + (CH 3 ) 2 (CH 2 ) 3 SO 3 , —NH(CH 2 ) 2 N + (CH 3 ) 2 (CH 2 ) 2 CO 2 , —NH(CH 2 ) 3 N + (CH 3 ) 2 (CH 2 ) 3 SO 3 , —NH(CH 2 ) 3 N + (CH 3 ) 2 (CH 2 ) 2 CO 2 , —O(CH 2 ) 2 N + (CH 2 CH 3 ) 2 (CH 2 ) 3 SO 3 , —O(CH 2 ) 2 N + (CH 2 CH 3 ) 2 (CH 2 ) 2 CO 2 , —O(CH 2 ) 2 N + (CH 2 CH 2 CH 2 CH 3 ) 2  (CH 2 ) 3 SO 3 , —O(CH 2 ) 2 N + (CH 2 CH 2 CH 2 CH 3 ) 2 (CH 2 ) 2 CO 2  or —NH(CH 2 ) 3 Ncyclo-(CH 2 ) 3 SO 3 , and Ncyclo- is a heterocyclic structure or a heterocyclic derivative containing at least one nitrogen atom, 
     
     
         18 . A process for modifying the surface of a silicon-containing polymer, the process comprising the steps of:
 forming a reaction mixture comprising the silicon-containing polymer, a polymerization monomer, a free radical initiator system and a solvent system, the polymerization monomer comprising a zwitterionic monomer and the free radical initiator system comprising a persulfate; and   polymerizing the polymerization monomer in the reaction mixture to form a surface modification polymer on the surface of the silicon-containing polymer, wherein the silicon-containing polymer does not undergo a plasma treatment and is not imbibed with an initiator or monomer.   
     
     
         19 . A process for modifying the surface of a silicon-containing polymer, the process comprising the steps of:
 forming a reaction mixture comprising the silicon-containing polymer, a polymerization monomer, a free radical initiator system and a solvent system, the polymerization monomer comprising a zwitterionic monomer and the free radical initiator system comprising one or more of: (i) a peroxide and a metal salt; (ii) a peroxide and a reducing agent; (iii) an inorganic reductant and an inorganic oxidant; (iv) an organic/inorganic redox pair; (v) a monomer that is capable of acting as a component of the redox pair of item (iv); and (vi) a free radical initiator; and
 polymerizing the polymerization monomer in the reaction mixture to form a surface modification polymer on the surface of the silicon-containing polymer, wherein the silicon-containing polymer does not undergo a plasma treatment and is not imbibed with an initiator or monomer. 
   
     
     
         20 . The process of  claim 19  wherein the peroxide is selected from the group consisting of benzoyl peroxide, lauroyl peroxide, hydrogen peroxide, dicumyl peroxide, tert-butyl hydroperoxide, tert-butyl peroxide, cumene hydroperoxide, cyclohexanone peroxide, dicumyl peroxide, lauroyl peroxide, and 2,4-pentanedione peroxide. 
     
     
         21 . The process of  claim 19  wherein the metal salt is selected from Fe(II) chloride, Fe(II) sulfate, ammonium Fe(II) sulfate, and Fe(II) gluconate. 
     
     
         22 . The process of  claim 19  wherein the reducing agent is selected from Fe 2+ , Cr 2+ , V 2+ , Ti 3+ , Co 2+ , Cu + , or amines; and transition metal ion complexes. 
     
     
         23 . The process of  claim 19  wherein the inorganic reductant is selected from the group consisting of Fe 2+ , Ag + , Cu 2+ , Fe 3+ , ClO 3− , and H 2 O 2 . 
     
     
         24 . The process of  claim 19  wherein the inorganic oxidant is selected from the group consisting of —O 3 SOOSO 3 , HSO 3   − , SO 3   2− , S 2 O 3   2− , and S 2 O 5   2− . 
     
     
         25 . The process of  claim 19  wherein the organic-inorganic redox pair comprises, respectively, an alcohol and Ce 4+ , V 5+ , Cr 6+ , Fe 3+ , or Mn 3+ . 
     
     
         26 . The process of  claim 19  wherein the monomer capable of acting as a component of the redox pair of item (iv) is selected from thiosulfate plus acrylamide, thiosulfate plus methacrylic acid, and N,N-dimethylaniline plus methyl methacrylate. 
     
     
         27 . The process of  claim 19  wherein the free radical initiator is selected from potassium persulfate, sodium persulfate, ammonium persulfate, peracetic acid, and tert-amyl peroxybenzoate, 4,4-azobis(4-cyanovaleric acid), 1,1′-azobis(cyclohexanecarbonitrile), 2,2′-azobisisobutyronitrile (AIBN), benzoyl peroxide, 2,2-bis(tert-butylperoxy)butane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, 2,5-bis(tert-Butylperoxy)-2,5-dimethyl-3-hexyne, Bis(1-(tert-butylperoxy)-1-methylethyl)benzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl hydroperoxide, tert-butyl peracetate, tert-butyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxy isopropyl carbonate cumene hydroperoxide, cyclohexanone peroxide, dicumyl peroxide, lauroyl peroxide, and 2,4-pentanedione peroxide. 
     
     
         28 . An article formed by the process of  claim 1 . 
     
     
         29 . The article of  claim 28  wherein the article is a contact lens.