Preparation, Optimization and Characterization of Podophyllotoxin Loaded Chitosan Microparticles by Ionic Cross-Linking Method

In order to improve the short metabolic time and low bioavailability of podophyllotoxin (PPT) in the body, podophyllotoxin loaded chitosan microparticles (PPT-CS-MPs) were prepared by ionic cross-linking method. The preparation conditions optimized by single factor experiment and response surface methodology were as follows: 2 mg/mL of chitosan, 1 mg/mL of TPP, acetic acid pH 3-4, 3 min of homogenizing time, 7 Kr/min of homogenizing rate, 40 min of magnetic stirring time. The PPT loading capacity of the PPT-CS-MPs was observed as 31 mg/g, and the encapsulation efficiency was up to 50.32%. The morphologies of the system were observed by scanning electron microscopy (SEM), and it showed the spherical microparticles with d(0.5) 58.14 mu m. The FTIR results showed that there was a weak physical interaction between PPT and chitosan. The DSC analysis indicated the formation of non-crystallinic PPT in microparticles. The in vitro release studies demonstrated longer release properties of PPT-CS-MPs. Cell cytotoxicity results showed the better cytotoxicity of PPT-CS-MPs. This work suggested that the prepared PPT-CS-MPs could realize slow release characteristics and improve the utilization, which exhibit good potential for the new formulation development of PPT.