Effect of polymer terminal groups on the drug release and experimental characterization of an electrospun naringin-loaded microsphere/sucrose acetate isobutyrate (SAIB) depot

The study was designed to develop an improved in situ injection drug delivery system by preparing naringin (Ng)-loaded electrospray microspheres with different terminal groups PLGA and studying their effect on drug release and related properties of naringin-loaded electrospray microspheres/sucrose acetate isobutyrate (Ng-m-SAIB) depot. The electrospray technique was used to prepare microspheres, that were characterized for their shapes and size distribution, as well as the related properties of the Ng-m-SAIB depot were tested. The initial drug release rate of hydroxyl-terminated microspheres (OH-Ng-m) was lower than that of carboxyl-terminated microspheres (COOH-Ng-m) and ester-terminated microspheres (COOR-Ng-m). The burst release, on the first day after preparing the mixed depots of OH-/COOH/COOR-Ng-m-SAIB, was significantly decreased from 43.9%, 47.4%, and 56.1% to 1.6%, 2.4%, and 3.9%, respectively. During the 88-day release profile, OH-Ng-m-SAIB had a low drug release (1.39% per day) in the early stage, yet maintained a relatively stable drug release. These findings suggest that by modifying the PLGA terminal groups in electrospray microspheres, the drug release profile of Ng-m-SAIB depot can be effectively tailored.