Poly orthoesters hydrolysis

Poly(orthoesters) represent the first class of bioerodible polymers designed specifically for dmg deUvery appHcations (52). In vivo degradation of the polyorthoester shown, known as the Al amer degradation, yields 1,4-cydohexanedimethanol and 4-hydroxybutyric acid as hydrolysis products (53). 

Polyorthoesters have been used as biomaterials, for example, in drug delivery systems (Suggs and Mikos, 1996). As a typical example, Heller et al. synthesized a poly(orthoester) from 3,9-bis(ethylidene-2,4,8,10-tetraokisaspiro[5,5]-undecane) and glycols (Fig. 14.25). They are highly susceptible to hydrolysis therefore, in the environment, they undergo hydrolytic degradation with subsequent assimilation by environmental microbes. 

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