Biomedical Polyurethanes

Abstract

The invention is directed to biomedical polyurethanes. The invention is particularly directed to biomedical polyurethanes with improved biodegradability and to an improved preparation of the biomedical polyurethanes. In particular the present invention provides a biomedical polyurethane having the formula (A-B-C-B) n , wherein A denotes a polyol, B denotes a diisocyanate moiety, C denotes a diol component and n denotes the number of recurring units, and wherein the B-C-B segment is bioresorbable.

1 . A biomedical polyurethane having the formula A-B-C-B n , wherein A denotes a polyol, B denotes a diisocyanate moiety, C denotes a diol component and n denotes the number of recurring units, wherein the B-C-B segment is bioresorbable, and wherein B is selected from the group consisting of 1,4-butane diisocyanate (BDI), 1,5-pentane diisocyanate (PDI), 1,6-hexyl diisocyanate (HDI), 1,7-heptyl diisocyanate (HpDI), 1,8-octyl diisocyanate (ODI), 1,9-nonyl diisocyanate (NDI), 1,10-decyl diisocyanate (DDI), methylene bis(4-cyclohexylisocyanate), 2,6-diisocyanatohexanoate and esters thereof (L-lysine diisocyanate, LDI), 5-isocyanate-1-(isocyanomethyl)-1,3,3- trimethylcyclohexane (isophorondiisocyanate, IPDI) and combinations thereof; and wherein C is selected from the group consisting of glycol, diethylene glycol, 1,4-butane diol (BDO), 1,5-pentane diol (PDO), 1,6-hexyl diol (HDO), 1,7-heptyl diol (HpDO), 1,8-octyl diol (ODO), 1,9-nonyl diol (NDO), 1,10-decyl diol (DDO), N-methyl diethanolamine (N-MDEA), 2,2-bis(hydroxymethyl)propanoic acid, tartartic acid, polyethylene glycol, polycaprolactone, poly lactide and combinations thereof. 
     
     
         2 . The biomedical polyurethane according to  claim 1 , wherein the B-C-B segment has a multiform block length. 
     
     
         3 . The biomedical polyurethane according to  claim 1 , wherein the B-C-B segment is based on two diisocyanate units and comprises more than 12 carbon atoms. 
     
     
         4 . The biomedical polyurethane according to  claim 1 , wherein at least one of the diisocyanate moieties (B) in B-C-B has a different length than the diol component (C). 
     
     
         5 . The biomedical polyurethane according to  claim 2 , wherein less than 60% of the B-C-B segments have the same length. 
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . The biomedical polyurethane according to  claim 1 , wherein C is at least partially based on a molecule comprising three or more alcohol groups in an amount of 0.01 to 10 mol%. 
     
     
         9 . The biomedical polyurethane according to  claim 1 , wherein the polyol comprises a prepolymer that is at least partially based on a random copolyester. 
     
     
         10 . The biomedical polyurethane according to  claim 9 , wherein the random copolyester is at least partially based on 5 to 95 mol% of lactide and 5 to 95 mol% ε-caprolactone. 
     
     
         11 . The biomedical polyurethane according to  claim 1 , for use in a method of the treatment of nasal wounds, nerves, meniscal injuries, skin and/or veins. 
     
     
         12 . A medical device such as a foam or a sheet, comprising the biomedical polyurethane according to  claim 1 . 
     
     
         13 . A method for the preparation of a biomedical polyurethane having the formula A-B-C-B n , wherein A denoted a polyol, B denotes a diisocyanate moiety, C denotes a diol component and n denotes the number of recurring units, said method comprising the step of:
 i) reacting the polyol A with the diisocyanate B to form an isocyanate terminated polyol B-A-B, followed by;   ii) determining the amount of isocyanate groups [R-NCO], followed by;   iii) reacting the isocyanate terminated polyol B-A-B with the diol component C to form the biomedical polyurethane having the formula A-B-C-B n .   
     
     
         14 . The method according to  claim 13 , wherein the amount of the isocyanate groups [R-NCO] is monitored during step iii) using FT-IR. 
     
     
         15 . The method according to  claim 13 , wherein the diol component C comprises two or more different diol compounds that differ in their respective lengths such that the B-C-B segment in the biomedical polyurethane has a multiform length. 
     
     
         16 . The method according to  claim 13 , further comprising a step of forming a medical device such as a foam or a sheet of the biomedical polyurethane.