New Biodegradable Poly(l-lactide)-Block-Poly(propylene adipate) Copolymer Microparticles for Long-Acting Injectables of Naltrexone Drug.

In the present study, novel block copolymers of poly(l-lactide)-block-poly(propylene adipate) (PLLA--PPAd) were synthesized in two ratios, 90/10 and 75/25 and were further investigated as long-acting injectable (LAI) polymeric matrices in naltrexone base microparticle formulations. The synthesized polymers were characterized by H-NMR, C-NMR, FTIR, XRD, TGA and DSC. NMR and FTIR spectroscopies confirmed the successful synthesis of copolymers while DSC showed that these are block copolymers with well-defined and separated blocks.