Determination of content and entrapment efficiency of oridonin nanoparticles

Objective To establish a method to determine the content and entrapment efficiency of oridonin capsulated in nanoparticles. Method The HPLC analysis was carried out on a Diamonsil C18(4. 6mm×250mm,5 μm) column with mobile phase consisted of methanol-H2O(60:40) at a flowrate of 1. 0 m L·min-1. The detection wave length was at 240 nm and the column temperature was 30℃. The free drug was isolated by Gel-filtration for the entrapment efficiency determination. Result The1 inear range of oridonin was 2.0 ~200μg·m L-1(γ=0. 9999). The average recovery was 102.5%(RSD 1.56%); 97.8%(RSD 1.37%); 98.3%(RSD 0.22%)respectively at low, middle and high concentration;97.8%(RSD 1.37%);98.3%(RSD 0.22%), respectively.The average entrapment efficiency was 21. 8%. Conclusion This method is simple,precise and replicable and it can be used to determine the content of total oridonin in nanoparticles and entrapment efficiency.