Synthesis and Properties of a Star-Shaped Poly( ϵ -Caprolactone)–Ibuprofen Conjugate

Abstract

A series of novel star-shaped poly(ϵ-caprolactone) (PCL) biodegradable polyesters were synthesized through ring-opening polymerization of ϵ-caprolactone in the presence of a poly(amidoamine) (PAMAM) dendrimer initiator. The polymers (PAMAM/PCLs) were obtained with a high yield (92%) and a number-average molecular weight of up to 14 000 g/mol. The nonlinear structure of PAMAM/PCLs was confirmed by nuclear magnetic resonance, gel-permeation chromatography, thermogravimetric analysis and differential scanning calorimetry. Thermal analysis indicated that the star-shaped PAMAM/PCLs had a melting point, degree of crystallinity, glass transition temperature and maximum decomposition temperature all lower than those of linear PCL. Ibuprofen (IBU), a popular non-steroidal anti-inflammatory drug, was co-valently (ester) bonded to the PAMAM/PCL molecules using the DCC/DMAP coupling method (DCC, N,N'-dicyclohexylcarbodiimide; DMAP, 4-(dimethylamino)pyridine). A high drug content (33.1 mol%) in the conjugate was obtained. The in-vitro drug-release profiles of IBU from the PAMAM/PCL/IBU conjugate were examined and found adequate for drug-carrier applications of our star-shaped polymers.

Pamidronate-Conjugated Biodegradable Branched Copolyester Carriers: Synthesis and Characterization

“…It was noted that there are unreacted hydroxyl groups in the bis-MPA molecule. This fact may be attributed to the change in the density and distribution of hydroxyl groups on the surface of the initiator and the stearic hindrance of the attached growing copolymer chains [ 20 ]. However, it was difficult to find and discriminate unreacted hydroxyl groups of bis-MPA moiety on 1 H-NMR spectra.…”

Enzymatic Polymerization of an Ibuprofen-Containing Monomer and Subsequent Drug Release

“…The lack of monomer present in the reaction mixture was confirmed by NMR and IR spectroscopies. Chloroform was chosen because it is the preferred solvent to terminate the lipase reactions; despite the use of this solvent in this one step, our overall synthetic methods are greener than traditional methods; other methods to achieve similar reactions utilize excess carbodiimides, chlorinated solvents, and metal catalysts often used in contrast to solvent‐free, catalytic reactions, safer solvents, and enzyme catalyst. GPC analysis indicated that M w values were moderate and PDI values narrow (Table ) substantiating that an additional purification step was unnecessary.…”

Conjugation of ß-Adrenergic Antagonist Alprenolol to Implantable Polymer-Aescin Matrices for Local Delivery

“…It was noted that there are unreacted hydroxyl groups of aescin in the resulting branched copolymers. This fact may be attributed to the change in the density and distribution of hydroxyl groups on the surface of the initiator and the stearic hindrance of the attached copolymer chains [20]. The resulting branched copolymers were characterized by 1 H, 13 C NMR and FTIR analysis (Figure 1, as well as Figures S1 and S2, Supplementary Material).…”