Determination of the content and entrapment efficiency of SN-38 in liposomes

Objective To establish an RP-HPLC method for the determination of 7-ethyl-10-hydroxyl- camptothecin (SN-38) content and calculate the encapsulation efficiency of SN-38 in the liposomes. Methods An RP-HPLC method was established to measure SN-38 content using CenturySIL C18-BDS column (200 mm× 4.6 mm, 5 μm) and the drug content was tested at detection wavelength 381 nm. The encapsulation efficiency of SN-38 in the liposomes was determined by separating free SN-38 from drug loaded liposomes using Sephadex column. Results In the established method, a linear correlation between drug concentration and peak area was established in the SN-38 concentration range of 1.68-16.80 mg·L-1(r =0.999 7, n=5). The average drug concentration was 28.90 mg·L-1, and the entrapment efficiency was ﹥80%. Conclusion The method established in this study is simple,accurate,sensitive for the determination of SN-38 content and entrapment efficiency in the liposomes.