Synthesis and Evaluation of Novel Polyester-Ibuprofen Conjugates for Modified Drug Release

Abstract

Ibuprofen was conjugated at different levels to a novel polyester, poly(glycerol-adipate-co-ω-pentadecalactone) (PGA-co-PL), via an ester linkage to form a prodrug. The conjugates were characterized by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), infrared (IR), gel permeation chromatography (GPC), ultraviolet (UV), and high-performance liquid chromatography (HPLC). The conjugates had a molecular weight between 18 and 24 kDa, and there was a suppression of the free hydroxyl groups within the conjugated polymer. DSC scans showed a lowering of the melting point (T_m) when compared with the polyester alone and a difference in the number and area of T_m peaks. Drug release studies showed an initial burst release (13–18%) followed thereafter by very slow release (maximum 35% after 18 days). Continuous work may produce ester-linked conjugates that are sufficiently labile to allow for complete release of ibuprofen over the time period studied.

Keywords:

• polyesters
• polymer degradation
• modified release
• conjugation
• ibuprofen