Interactions of amidated acids with heparin.
Raman and NMR studies are performed to characterize the solution structures of complexes between heparin and a group of amidated acids, which act as delivery agents that facilitate the gastrointestinal absorption of orally administered heparin. At concentrations typically employed for the oral drug delivery of heparin, the contact points between heparin complexed with the delivery agents include points near the OH groups of heparin. The results suggest that heparin interacts rather nonspecifically with the amidated acids as monomers and with self-associated complexes of the delivery agents. It is also found that the carboxyl groups of at least one of the bioactive delivery agents easily protonates when it forms complexes with itself or heparin. This attribute may be one reason why this class of compounds is effective in the oral delivery of heparin.
Desamero
Ruel Z B
RZ
Department of Physics, City College of New York, New York, New York 10031, USA.
Cheng
Hu
H
Cahill
Sean
S
Girvin
Mark
M
Deng
Hua
H
Callender
Robert
R
Rath
Parshuram
P
Variano
Bruce
B
Smart
John E
JE
D000143:Acids / Q000737:chemistry* / Q000378:metabolism; D000577:Amides / Q000737:chemistry* / Q000378:metabolism; D000925:Anticoagulants / Q000737:chemistry* / Q000378:metabolism; D006493:Heparin / Q000737:chemistry* / Q000378:metabolism; D066298:In Vitro Techniques; D007477:Ions; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D011522:Protons; D012996:Solutions; D013059:Spectrum Analysis, Raman; D013329:Structure-Activity Relationship; D014732:Vibration
D000143:Acids; D000577:Amides; D000925:Anticoagulants; D007477:Ions; D046911:Macromolecular Substances; D011522:Protons; D012996:Solutions; D006493:Heparin