Monitoring of peptide acylation inside degrading PLGA microspheres by capillary electrophoresis and MALDI-TOF mass spectrometry.
The purpose of this research was to assess the acylation reactions of peptides, salmon calcitonin (sCT), human parathyroid hormone 1-34 (hPTH1-34) and leuprolide, in poly(lactic-co-glycolic acid) (PLGA) microspheres. Capillary electrophoresis (CE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used for determining and monitoring peptide acylation and quantitating acylation products in the degrading PLGA microspheres. In the degrading PLGA microspheres of sCT and hPTH1-34, the acylation products were observed and determined to be adducts with glycolic acid units from degradable PLGA polymer by MALDI-TOF MS. In the microsphere of leuprolide, however, the acylation product was not observed even after 28 days of incubation at the release medium, which represents the different stabilities among peptides according to the primary structure. As the leuprolide contains tyrosine and serine having hydroxyl group of nucleophilic amino acids, the acylation reaction of peptide is shown to be mainly due to the primary amino groups of N-terminus or lysine residue. The complementary use of CE and MALDI-TOF MS will be useful for searching the counter measures as well as determining the peptide acylation in the manufactured formulations on the market.
Drug Targeting Laboratory, College of Pharmacy, SungKyunKwan University, 300 Chonchon-dong, Jangan-ku, Suwon 440-746, South Korea.
Dong Hee
DH
Na
Yu Seok
YS
Youn
Sang Deuk
SD
Lee
Mi-Won
MW
Son
Won-Bae
WB
Kim
Patrick P
PP
DeLuca
Kang Choon
KC
Lee
D000215:Acylation; D000595:Amino Acid Sequence; D000818:Animals; D002116:Calcitonin / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry; D019075:Electrophoresis, Capillary; D006016:Glycolates / Q000737:chemistry; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry*; D016729:Leuprolide / Q000737:chemistry; D008239:Lysine / Q000737:chemistry; D008863:Microspheres; D008969:Molecular Sequence Data; D010281:Parathyroid Hormone / Q000737:chemistry; D036361:Peptide Hormones / Q000737:chemistry*; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D012474:Salmon; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D004337:Drug Carriers; D006016:Glycolates; D010281:Parathyroid Hormone; D036361:Peptide Hormones; D011108:Polymers; C031149:glycolic acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D002116:Calcitonin; D016729:Leuprolide; D008239:Lysine