Fabrication, Optimization, and In Vitro and In Vivo Characterization of Intra-vitreal Implant of Budesonide Generally Made of PHBV.

Drug delivery to vitreous in comparison with drug delivery to the other parts of the eye is complicated and challenging due to the existence of various anatomical and physiological barriers. Developing injectable intra-vitreal implant could be beneficial in this regard. Herein, poly(hydroxybutyrate-co-valerate) (PHBV) implants were fabricated and optimized using response surface method for budesonide (BZ) delivery. The acquired implants were characterized in regard to the stability of the ingredients during fabrication process, drug loading amount, and drug release pattern (in PBS-HA-A and in vitreous medium). According to this research and statistical analysis performed, first HV% (hydroxyvalerate) then molecular weight and ratio of PEG as pore former affect respectively release rate and burst strength of BZ with different coefficients. Drug release profile in rabbit eye correlated well with that of in vitro (R = 0.9861, p ˂ 0.0001). No significant changes were seen in ERG waves, intraocular pressure, and histological studies during the in vivo part of the project. Using 8% HV, 20% PEG/PHBV, and higher molecular weight PEG (i.e., 6000), the optimum formulation was achieved. Toxicity and biocompatibility of the optimized formulation, which were evaluated in vivo, indicated the suitability of design implant for intra-vitreal BZ delivery. Grapical abstract.