Preparation of biodegradable porous poly(butylene succinate) microspheres

Abstract

The aim of this study was to determine the optimal conditions for the fabrication of porous microspheres based on poly(butylene succinate), PBS. The biodegradable non-porous PBS microspheres were prepared by the oil-in-water (o/w) emulsion solvent evaporation method using poly(vinyl alcohol), PVA, as the surfactant. Fabrication conditions, such as stirring rate, organic/aqueous ratio, PBS concentration and surfactant (PVA) concentration, which have an important influence on both the particle size and the morphology of the microspheres, were varied. Scanning electron microscopy, SEM, observations confirmed the size, size distribution and surface morphology of the microspheres. The optimal conditions for the preparation of the non-porous microspheres were found to be: concentration the PBS solution, 10 mass%; PVA concentration, 1 mass%; the organic/ aqueous ratio CHCl3/H2O = 1/20 and stirring rate 800 rpm. Porous PBS microspheres were fabricated under the optimal conditions using various amounts of hexane and poly(ethylene oxide), PEO, as porogens. The influence of the amount of porogen on the pore size and the particle size was investigated using SEM and the apparent density. The microspheres exhibited various porosities and the pore sizes. The average particle size of the microspheres with PEO as the porogen was from 100 to 122μm and that of the microspheres with hexane as the porogen was from 87 to 97μm. The apparent density of the porous microspheres with PEO as the porogen, from 0.16 to 0.23 g/cm3, was much smaller than the non-porous microspheres, 0.40 g/cm3. In the in vitro degradation experiments, the porous microspheres were incubated in phosphate buffer solution (pH 7) at 37°C. After incubating for one month, the microspheres showed significant extent of the hydrolytic degradation of the porous PBS microspheres

Optimization of preparation conditions of poly(ε-caprolactone) microspheres for controlled release of carbamazepine

“…Preliminarna ispitivanja su pokazala da su veličine mikrosfera dobijenih bez korišćenja homogenizatora velike snage pri formiranju emulzije značajno veće. Kada je upotrebljena brzina mešanja za formiranje emulzije bila samo 1000 o min -1 , veličina mikrosfera na bazi PCL je bila preko 100 μm, slično kao u slučaju drugih biodegradabilnih poliestara, kao što je poli(butilen sukcinat) [25]. Ovo pokazuje da brzina mešanja ima veliki uticaj na prečnik mikrosfera, i da je korišćenjem homogenizatora za postizanje velikih brzina mešanja (preko 10000 o min -1 ) omogućeno dobijanje mikročestica čiji je srednji prečnik manji od 10 μm.…”