Abstract:In this study, we developed biodegradable lidocaine-/vancomycin-/ceftazidime-eluting poly(D,L-lactide-co-glycolide) (PLGA) nano/microparticulate carriers using an electrospraying process, and we evaluated the release behaviors of the carriers in knee joints. To prepare the particles, predetermined weight percentages of PLGA, vancomycin, ceftazidime, and lidocaine were dissolved in solvents. The PLGA/antibiotic/lidocaine solutions were then fed into a syringe for electrospraying. After electrospraying, the morphology of the sprayed nano/microparticles was elucidated by scanning electron microscopy (SEM). The in vitro antibiotic/analgesic release characteristics of the nano/microparticles were studied using high-performance liquid chromatography (HPLC). In addition, drug release to the synovial tissues and fluids was studied in vivo by injecting drug-loaded nano/microparticles into the knee joints of rabbits. The biodegradable electrosprayed nano/microparticles released high concentrations of vancomycin/ceftazidime (well above the minimum inhibition concentration) and lidocaine into the knee joints for more than 2 weeks and for over 3 days, respectively. Such results suggest that electrosprayed biodegradable nano/microcarriers could be used for the long-term local delivery of various pharmaceuticals.

We develop novel analgesic-eluting nanofiber-incorporated ureteral stents that offer sustained release of lidocaine and ketorolac for local drug delivery. Lidocaine and poly(D,L)-lactide-co-glycolide (PLGA) were dissolved in hexafluoroisopropanol and were electrospun into nonwoven nanofibers onto the surface of ureteral stents. This was followed by electrospinning of another layer of PLGA nanofibers containing ketorolac. Electrospun drug-loaded nanofibers were then characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and water contact angle analysis. In addition, the elution behavior characteristics of the analgesics, both in vivo and in vitro, from the nanofiber-incorporated stents were evaluated. Experimental results indicate that the analgesic-eluting ureteral stents could liberate high strengths of analgesics in vitro and in vivo for at least 50 and 30 days, respectively. The analgesic-eluting nanofiber-incorporated ureteral stents are potentially applicable for alleviating the discomfort associated with stent implant.

Co-axial electrospraying is a simple and versatile process, achieving liquid atomization through electrical forces, to produce core–shell-structured nano/microparticles. Despite its advantages in terms of preparing particles with sizes ranging from 300–500 µm down to 50–70 nm, the optimization of the co-axial electrospraying process remains a challenge. In this study, we investigated experimentally the effects of processing parameters on the size distribution of co-axially electroprayed poly(d,l-lactide-co-glycolide) (PLGA) microparticles. The effects of various parameters, including voltage, flow rate ratio, travel distance, and polymeric concentration, were examined using a factorial experimental design. It was found that the particle size of electrosprayed core–shell microparticles decreases with the voltage and travel distance, and it increases with the flow rate of the solutions and the PLGA concentration in the solutions. Furthermore, to verify the existence of proteins in the co-axially electrosprayed microparticles, PLGA was used as the shell, and recombinant enhanced green fluorescent protein (reGFP) was employed as the core material. Transmission electron microscopy (TEM) and laser scanning confocal microscopy (LSCM) were employed to confirm the core–shell structure of the microparticles. The experimental results demonstrated that under optimum conditions, core–shell-structured microparticles can be successfully prepared using a protein with high activity at the core.