Study On PCL Based Micro/nanoparticles For Drug Delivery

Poly (ε-caprolactone) (PCL), a biodegradable polymer, is used as sustained and controlled drug release carrier, due to its excellent biocompatibility and drug penetrability. As an amphiphilic block copolymer, methoxy poly (ethylene glycol)-poly (ε-caprolactone) (MPEG-PCL) is improved in characteristics and has been widely studied in drug delivery system in recent years.PCL and MPEG-PCL were synthesized via ring-opening polymerization ofε-CL using Novozym 435 as biocatalyst, which makes no toxic chemicals residue. Tyrosine kinase inhibitor (CH331), a new anticancer drug with better solubility in water, and taxol, which has poor solubility in water, were used as model drug, respectively, to prepare CH331 loaded PCL microspheres and taxol loaded MPEG-PCL nanoparticles.Since CH331 is a novel antitumor agent,data is lacking on its physical and chemical character. It is necessary to study its solubility in different media for effective encapsulation. CH331-PCL microspheres were prepared by S/O/W solvent evaporation method. Results showed that only when the CH331 particles were pretreated with a suitable amount of ethanol could lead to more uniform sizes, better appearance and higher drug loading for the microspheres. The solubility of CH331 in outer aqueous phase played a significant role in encapsulation efficiency and in vitro drug release of microspheres.MPEG-PCL with different composition (MPEG/PCL ratio) were applied as emulsifier and drug carrier, respectively, in the solvent evaporation technique to fabricate taxol-loaded nanoparticles. As a newly employed emulsifier, MPEG-PCL is biodegradable and can stabilize emulsions at low concentration. The feed of drug to copolymer was investigated for higher encapsulation efficiency. The effects of different concentration of MPEG-PCL with different composition as emulsifier on the characteristics of nanoparticles were also studied. The encapsulation efficient could reach 52.5±3.9%. The produced nanoparticles were all in a fine spherical shape with good stability and the hydrodynamic diameters ranged from 70 nm to 120 nm. Nanoparticles with drug loading around 5% had a sustained drug release for 7 days.