Retinoic acid-loaded alginate microspheres as a slow release drug delivery carrier for intravitreal treatment

Pharmacotherapy were the mainstream methods for the treatment of proliferative vitreoretinopathy (PVR), one of the leading causes of blindness. Due to the negligible side-effects, retinoic acid (RA) was considered to be a promising candidate drug. However, it was still a challenge to deliver drugs into vitreous with both long-term efficiency and biosafety. Sodium alginate was considered to be an excellent drug carrier owing to its controlled size, good biocompatibility and degradability. Based on a one-time synthetic strategy of preparing RA-sodium alginate microspheres, the study was aimed to establish a non-toxic and effective RA slow release platform. The prepared microspheres were smoothly round and relatively homogenous with an average diameter of 95.7 ± 9.6 μm. RA release rate from RA-MS was assessed in vitro by UV spectrometry and in vivo by high performance liquid chromatography, achieving a steady, long-term and effective level of RA. The biocompatibility of RA-MS was further confirmed through histology using HE staining and fundus microscope, finding no inflammation and other toxic response. Collectively, it could be concluded that RA-MS possessed a great potential in retinal PVR treatment.