PEGylation defined

Pegylation, defined as the chemical process by which polyethylene glycol chains are attached to protein and peptide drugs, have been successfully applied to produce peginterferon alfa-2a (PEGASYS) and peginterferon alfa-2b (PEG-Intron), both of which have been approved by the FDA for the treatment of chronic hepatitis C [203]. 

Neutropenia associated with interferon or pegylated interferon therapy is defined as an absolute neutrophil count (ANC) of less than 1000 cells/mm3 in rare cases, an ANC less than 500 cells/mm3 maybe observed. The neutropenia is more common and in some cases more severe with pegylated interferon than with unmodified interferon. Neutropenia usually occurs within the first 2 weeks after initiating either formulation of interferon, with the WBC count stabilizing by week four or six. The neutropenia is reversible upon discontinuing therapy. Granulocyte colony-stimulating factor has been used as an adjunctive therapy for interferon-induced neutropenia in hepatitis patients.44... 

Anytime the term process chemist is used, it usually relates to the development of a small synthetic molecule. However, there has been a growth explosion in the development of macromolecules as of late. These may include proteins, small molecules attached to proteins, pegylated proteins, DNA and RNA fragments, oligonucleotides, monoclonal antibodies, and even personalized medicines in vaccines being made from a specific patient to treat the same patient. As this is a growing trend within the pharmaceutical industry, the term process chemist should include development chemists who are involved in all of the above-mentioned areas. A major difference between these areas and the development of small molecules is that the process to manufacture these complex products usually defines the product versus the other way around for small molecules, where the product defines the process. 

Well-defined composition Subsequent derivatization (ie 2 step PEGylation)... 

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