Ghrelin-liposome interactions: Characterization of liposomal formulations of an acylated 28-amino acid peptide using CE

TY - JOUR

T1 - Ghrelin-liposome interactions

T2 - Characterization of liposomal formulations of an acylated 28-amino acid peptide using CE

AU - Østergaard, Jesper

AU - Møller, Eva Horn

PY - 2010/1

Y1 - 2010/1

N2 - Ghrelin is a pharmacologically interesting peptide hormone due to its effects on appetite and metabolism. The cationic, octanoylated 28 amino acid peptide has a short biological half-life; thus, prolonged release formulations are of interest. Acylated peptides have been suggested to bind to or be incorporated into liposomes. Formulations based on neutral dipalmitoylphosphatidylcholine (DPPC) liposomes and phosphatidylcholine: cholesterol (70:30 mol%) liposomes, and negatively charged dipalmitoylphosphatidylcholine: dipalmitoylphosphatidylserine (DPPC:DPPS) (70:30 mol%) liposomes (2mM total lipid concentration) were characterized using ACE. Pre-equilibrium CZE and frontal analysis CE methods circumventing capillary wall adsorption of the peptide and the liposomes and suitable for characterizing ghrelin-liposome interactions were developed. The cationic peptide exhibited low affinity (<10% bound) for DPPC and phosphatidylcholine:cholesterol (70:30 mol%) liposomes whereas electrostatic interactions caused a higher affinity for DPPC:DPPS (70:30 mol%) liposomes. Studies on desacyl ghrelin instead of ghrelin demonstrated the significance of the n-octanoyl side chain as an affinity providing moiety towards DPPC:DPPS liposomes (48 and 73% bound peptide, respectively). CE experiments showed that the binding was characterized by rapid dissociation kinetics.

AB - Ghrelin is a pharmacologically interesting peptide hormone due to its effects on appetite and metabolism. The cationic, octanoylated 28 amino acid peptide has a short biological half-life; thus, prolonged release formulations are of interest. Acylated peptides have been suggested to bind to or be incorporated into liposomes. Formulations based on neutral dipalmitoylphosphatidylcholine (DPPC) liposomes and phosphatidylcholine: cholesterol (70:30 mol%) liposomes, and negatively charged dipalmitoylphosphatidylcholine: dipalmitoylphosphatidylserine (DPPC:DPPS) (70:30 mol%) liposomes (2mM total lipid concentration) were characterized using ACE. Pre-equilibrium CZE and frontal analysis CE methods circumventing capillary wall adsorption of the peptide and the liposomes and suitable for characterizing ghrelin-liposome interactions were developed. The cationic peptide exhibited low affinity (<10% bound) for DPPC and phosphatidylcholine:cholesterol (70:30 mol%) liposomes whereas electrostatic interactions caused a higher affinity for DPPC:DPPS (70:30 mol%) liposomes. Studies on desacyl ghrelin instead of ghrelin demonstrated the significance of the n-octanoyl side chain as an affinity providing moiety towards DPPC:DPPS liposomes (48 and 73% bound peptide, respectively). CE experiments showed that the binding was characterized by rapid dissociation kinetics.

KW - Former Faculty of Pharmaceutical Sciences

U2 - 10.1002/elps.200900394

DO - 10.1002/elps.200900394

M3 - Journal article

C2 - 20024925

SN - 0173-0835

VL - 31

SP - 339

EP - 345

JO - Electrophoresis

JF - Electrophoresis

IS - 2

ER -