Separation of positional isomers of mono-poly(ethylene glycol)-modified octreotides by reversed-phase high-performance liquid chromatography.
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.
Park
Eun Ji
EJ
College of Pharmacy, Kyungsung University, 314-79 Daeyeon-dong, Nam-ku, Busan 608-736, South Korea.
Lee
Kang Choon
KC
Na
Dong Hee
DH
D056148:Chromatography, Reverse-Phase / Q000379:methods*; D007536:Isomerism; D008970:Molecular Weight; D015282:Octreotide / Q000737:chemistry* / Q000302:isolation & purification*; D011092:Polyethylene Glycols / Q000737:chemistry*
D011092:Polyethylene Glycols; D015282:Octreotide