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Investigation of drug release and 1 H‐NMR analysis of the in situ forming systems based on poly(lactide‐ co ‐glycolide)
Author(s) -
Mohamadnia Z.,
Ahmadi E.,
Rafienia M.,
Mirzadeh H.,
Mobedi H.
Publication year - 2009
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.1279
Subject(s) - polymer , plga , hydrolysis , solvent , materials science , nuclear chemistry , polymer degradation , proton nmr , biodegradable polymer , polymer chemistry , degradation (telecommunications) , chemical engineering , organic chemistry , chemistry , nanotechnology , nanoparticle , telecommunications , computer science , engineering
In situ forming biodegradable polymeric systems loaded with betamethasone (BTM) and betamethasone acetate (BTMA) were prepared using poly( DL ‐lactide‐ co ‐glycolide) (PLGA), ethyl heptanoate (EH), and N ‐methyl‐2‐pyrrolidone (NMP) as the biodegradable polymer, additive, and solvent, respectively. The drug release studies were carried out in buffer (pH = 7.4, 37°C) using high performance liquid chromatography (HPLC). 1 H‐NMR was used to determine the polymer degradation behavior, release mechanism, and interactions between the polymer and drug. The 1 H‐NMR spectra showed that all interactions between the polymer and drug were hydrogen bonding. Hydroxyl groups and fluorine in drugs were involved in hydrogen bonding with PLGA polymer. In 1 H‐NMR studies, we found that the degradation rate in the systems loaded with BTMA was higher than the systems loaded with BTM because BTMA is only slightly soluble and accelerates the hydrolysis of PLGA chains. The formulations loaded with BTM had obviously lower burst release compared with BTMA loaded samples. With respect to 1 H‐NMR spectra, the mechanism of BTM release is controlled by two effective factors: solvent removal and polymer degradation. Copyright © 2008 John Wiley & Sons, Ltd.