Abstract：To study the octreotide synthesis by solid—phase peptide synthesis，a novelmethod ispresented．In this method. the CTC resin.a conventional Fmoc．protocol and iodine-mediated oxidation were applied to make the disulphides formation of the octreotide． The final product was purificated by HPLC，and the purity reached 70.26％ ．The result indicates that the technology of solid—phase peptide synthesis is feasible for large—scale preparation of octreotide because of simplified procedures，high yield and purity．

Synthetic octreotide consists of two parts

（1）Solid phase synthesis of linear octapeptide.

（2）The cyclization of linear octadeptide.

Generally speaking, the metabolic stability and bioavailability of cyclic peptides are much higher than that of straight-chain peptides. In view of the many advantages of cyclic peptides, the research focus has shifted to the synthesis and biological evaluation of cyclic peptides in recent years. Reverse high performance liquid chromatography (RP - HPLC) is the most commonly used method for the separation and detection of polypeptides. The stationary phase is non-polar, while the mobile phase is a solvent system with stronger polarity than the stationary phase. Alkyl C18 was used as column packing for the separation of octreotide.

In this study, CTC resin (2 - CTC resin) was selected as the carrier,The linear polypeptide was synthesized by Fmoc synthesis method and then treated by cyclization.

The main instruments and equipment used in this experiment