title: Separation of positional isomers of mono-poly(ethylene glycol)-modified octreotides by reversed-phase high-performance liquid chromatography.
abstract: The purpose of this study was to develop a reversed-phase high-performance liquid chromatographic method (RP-HPLC) for separating each positional isomer from low- to high-molecular-weight mono-PEGylated octreotides prepared by polyethylene glycol (PEG) derivatives with various molecular weights (2, 5, or 20kDa). In the gradient elution using acetonitrile and 10mM phosphate buffer at pH 7.0 on a Phenomenex Gemini C-18 column (250mmx4.6mm id, 5microm), each positional isomer of the mono-PEGylated octreotides was completely resolved with good resolution (PEG-2K: 7.6, PEG-5K: 6.6, and PEG-20K: 3.1). The optimal RP-HPLC condition also resolved the degradation products of mono-PEG-octreotide isomers in thermal stability studies at 55 degrees C and enzymatic stability studies with trypsin. In conclusion, the developed RP-HPLC method will be valuable for studying the effect of PEGylation site and the attached PEG size on the physicochemical and pharmacological properties of PEGylated octreotides.
authors.affiliation: College of Pharmacy, Kyungsung University, 314-79 Daeyeon-dong, Nam-ku, Busan 608-736, South Korea.
authors.forename: Eun Ji
authors.initials: EJ
authors.lastname: Park
authors.forename: Kang Choon
authors.initials: KC
authors.lastname: Lee
authors.forename: Dong Hee
authors.initials: DH
authors.lastname: Na
mesh_terms: D056148:Chromatography, Reverse-Phase / Q000379:methods*; D007536:Isomerism; D008970:Molecular Weight; D015282:Octreotide / Q000737:chemistry* / Q000302:isolation & purification*; D011092:Polyethylene Glycols / Q000737:chemistry*
chemical_list: D011092:Polyethylene Glycols; D015282:Octreotide