hydroxypolycarbonates offer to the biomedical area hydroxyl functional polymers not now readily available to bind drugs , proteins , or carbohydrate polymers chemically or via hydrogen bonding to facilitate drug delivery and utility with subsequent biodegradability to acceptable byproducts . the cyclic carbonate from the monoketal diol of pentaerythritol polymerized in chcl 3 at 60 ° c . with et 2 zn catalyst in chcl 3 at 60 ° c . in 4 hours to a quantitative yield of high molecular weight , crystalline polymer , melt peak 199 ° c . and tg of 99 ° c . pcc is readily hydrolyzed with 80 % acetic acid to the water - insoluble but water - swollen hpc , poly - 1 , 3 - dioxan - 2 - one ], with m w = 3 . 1 × 10 4 . hpc degrades completely in vitro in & lt ; 16 hours in pbs - 1x buffer to pentaerythritol and presumably co 2 . this rapid degradation rate is decreased with random copolymers of hpc with cc , ε - caprolactone , or l - lactide . hpc and pcc may have important biomaterial applications as is and as the copolymers noted above or with ethylene oxide or other desirable comonomers . pcc and cc copolymers have properties attractive to the biomedical area as is or by conversion to the hpc product provided by hydrolysis or by in vivo enzymatic attack .