Study on methods for the determination of entrapment efficiency of solid lipid nanoparticles loading lappaconite hydrobromide

OBJECTIVE To establish a method for the determination of the entrapment efficiency of solid lipid nanoparticles loading lappaconite hydrobromide(1-SLN).METHODS The high pressure homogenization was used to prepare solid lipid nanoparticles loading lappaconite hydrobromide.The 1-SLN and free drugs were separated by dialysis method and ultrafiltration.The content of lappaconite hydrobromide was quantified by HPLC consisted of Kromasil C18 column,a mobile phase of 0.02 mol·L-1 sodium dihydrogen phosphate-acetonitrile(74∶26) with a flow rate of 1 mL·min-1 and UV detection wavelength at 252 nm.The methodology study and the optimization of determining condition were carried out.RESULTS Ultrafiltration could effectively separate the 1-SLN from free drugs.A calibrated linear curve of lappaconite hydrobromide concentration was within 10.0～120.0 μg·mL-1(r=0.999 9).The average entrapment efficiency of three batches of 1-SLN was 53.65%,with RSD of 0.97% by ultrafiltration.CONCLUSION Ultrafiltration was convenient,sensitive and accurate.It indicated that ultrafiltration was more suitable for the determination of entrapment efficiency.