Biological product stability/degradation

The HPLC procedures reported in the literature (see Table V) were developed mainly for biological and stability studies, and they do separate Melphalan from its hydrolytic degradation products. 

The degree of purity, as well as the individual and total amounts of degradation products of the biotechnological/biological product entered into the stability studies, should be reported and documented whenever possible. Limits of acceptable degradation should be derived from the analytical profiles of batches of the DS and DP used in the preclinical and clinical studies. 

For hydrophilic proteins and peptides the double emulsion/solvent evaporation method is considered as the most convenient because of its encapsulation efficiency and biologically active stability [43]. However, the double emulsion/solvent evaporation method posesses several liabilities such as the required use of toxic solvents that are not easy to fully eliminate (hydrophobic and halogenated solvent) and the inadequate protein release profile. [44-46]. Fxuthermore, the production of acid degradation products, particularly lactic acid, is the primary instability source for the encapsulated acid-labile protein or peptide [6,8],... 

Peptide synthesis from y9-amino acids is particularly attractive for first feasibility micro-reactor tests as there are no chiral centers which may complicate analysis of the products [5, 88]. y0-Peptides are also attractive owing to their stmctural and biological properties, especially concerning the stability versus degradation by peptidases as compared with their a-analogues (see original citations in [5]). 

---