Purpose:
To develop an electrohydrodynamic spray drying technique to fabricate moxifloxacin microparticle systems in order to achieve sustained antibiotic release for ocular treatments.
Methods:
Moxifloxacin-loaded PLGA microparticles were prepared using an electrohydrodynamic spray drying (electrospraying) technique. The antibiotic, Moxifloxacin HCl, was encapsulated in poly (lactic-co-glycolic acid) (PLGA) by dissolving both reagents in different solvents and electrospraying the solution using high voltages ranging from 11-13 kV. The microparticles were collected using distilled water, stored at -80 °C then lyophilized. The microparticles were then encapsulated into bioadhesive hydrogels: chondroitin sulfate-polyethylene glycol (CS-PEG) bioadhesive. The morphologies of the microparticles were examined using scanning electron microscopy (SEM). The release of Moxifloxacin was tested in vitro by submerging the vehicles in PBS buffer solution, taking samples at different time intervals and refreshing the solution. Drug concentration was determined using high performance liquid chromatography (HPLC).
Results:
In order to achieve an optimal, controlled release of moxifloxacin, we encapsulated the antibiotics in PLGA-based microparticles by carefully selecting solvent systems for electrospraying processing. The release speed of moxifloxacin using the solvent of methanol:dichloromethane (MeOH:DCM)=10:90 was found to be close to the one using the solvent of MeOH:DCM=20:80, while the release speed using the solvent of MeOH:DCM=30:70 was much slower than the other two solvent ratios. All of these conditions showed an effective release over ten days with the release concentration continuously higher than the minimum inhibitory concentration (MIC) (Figure 1). In contrast, the Moxifloxacin loaded in hydrogels was released rapidly within 24 hours.
Conclusions:
This study fabricated surfactant-free antibiotic-loaded polymeric microparticles using an electrospraying technique and achieved sustained release of Moxifloxacin HCl over more than ten days. A delivery system which incorporates a bioadhesive may potentially integrate antibiotic prophylaxis and wound healing.
Keywords: antibiotics/antifungals/antiparasitics