Study On Synthesis Of Star Type Polyethylene Glycol

The clinic impact of pharmic peptide without modification is weakened because pharmic peptide is immune to the body, therefore the use of pharmic peptide is limited. However, it should be efficient if it is modified with monomethoxypoly(ethylene glycol), which passes the attestation of FDA of America: (1) Immunity and antigenity of pharmic peptide are avoided. (2) dissolution and stability increase. (3) the half life is prolonged. It is shown that molecular weight of MPEG is larger and it is more efficient. And the single MPEG is commonly used as modificatory reagent presently, because of synthetical technology molecular weight of MPEG could not be made to be larger. In this dissertation, star type molecules with several MPEG chains are synthesized.In this dissertation, molecular weight of MPEG is 750 and 5000. The molecular weight of lysine conjugated with double MPEG₇₅₀ chains and single MPEG chain is 1240; The molecular weight of tris(hydroxymethyl)aminomethane conjugated with three MPEG₇₅₀ chains, double MPEG₇₅₀ chains and single MPEG chain is 2188; The molecular weight of dextrin conjugated with at least ten MPEG₇₅₀ chains is 9920. The molecular weight of lysine conjugated with double MPEG₅₀₀₀ chains and single MPEG₅₀₀₀ chain is 7440. The molecular weight of tris(hydroxymethyl)aminomethane conjugated with three MPEG5000 chains, double MPEG5000 chains and single MPEG₅₀₀₀ chain is 9230. The compounds are characterized by FT-IR, element analysis, ¹H-NMR and LC-MSD to investigate the molecular composition and structure, molecular weight.