Lactic acid and hydroxyl terminated polybutadiene assisted synthesis of vegetable oil based polyurethanes for sustained drug delivery systems

The present research aims to develop a series of biodegradable, sustainable and biocompatible, polyurethanes (PU-S1 to PU-S4). The synthesis of these polyurethanes involved a combination of different ratios of an epoxidized polyol (followed by ring opening with ethanol) extracted from soybean oil, along with hydroxylterminated polybutadiene (HTPB). The lactic acid was esterified with ethylene glycol to produce a sustainable chain extender which was used to increase the molecular weight of the final polymer. FTIR spectroscopy and scanning electron microscopy (SEM) were used for the characterization of the PU samples. The thermal degradation behavior and wetting ability of the PUs were also determined through contact angle, indicating a gradual decrease in hydrophilicity with increasing HTPB content finally made a little hydrophobic surface in the case of PU-S4 sample (contact angle = 96.46 degrees). The potential of these polyurethanes (PUs) as drug delivery systems was checked using gabapentin as a prototypical drug. It was dispersed into the polymer matrix via the solvent evaporation process. The analysis of drug release adhered to US Pharmacopeial guidelines was determined using 0.06 N HCl as the release medium. Sample PU-S4 showed a higher drug release, reaching 56.0 % after 6 h. Additionally, a regular trend was observed in different PU samples, suggesting an increase in HTPB content with a decrease in drug release.