Drug delivery degradation mechanism

The degradation of proteins in the solid state occur to a lesser extent and typically via different mechanisms than those that occur in solution [109,110]. Lyophilization is currently the more common technique in the manufacture of dried therapeutic proteins however, there is increasing interest in the use of spraydrying, owing to the unique physical nature of the spray-dried powder and its potential usefulness in protein drug delivery. 

Poly(esters) (Table 11.2) are the first class of polymers discussed, as they are the most widely investigated of all of the polymer families for oral protein delivery. Poly(esters) used for oral drug delivery have primarily been biodegradable polymers (Figure 11.1). Biodegradation is the primary delivery mechanism for poly(ester) polymers used for protein and peptide delivery. The degradation properties of poly(esters) are dependent on the monomers used to produce the poly(ester). Several poly(esters) are discussed in detail in the following sections. 

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