Objective To investigate the changes of serum concentration of
podophyllotoxin after topical application of lipo-some podophyllotoxin
suspension on rat skin. Methods SD rats were used in this study, which were divided into test group (ra=48) to receive application of liposome
podophyllotoxin (0.5%) suspension and control group (n=48) treated with 0.5% podophyllotoxin alcohol solution. Blood samples were obtained from the heart at 1, 2, 4, 6, 8, 10, 12 and 24 h respectively after drug application, and the serum concentration of podophyllotoxin was determined by
spectrofluorometry. Results The area under the curve of plasma drug concentration of the control group was 2.3-fold greater than that of the test group. Eight hours after drug application, the serum concentration of podophyllotoxin reached the peak in the test group, while in the control group, only two hours was needed to reach the peak. The peak serum level of podophyllotoxin in the test group were significantly lower than that of the control group (166.395?4.634 ng/ml vs 378.603 + 26.105 ng/ml, P<0.001). Conclusion The systemic absorption of podophyllotoxin in rats after its topical application in liposome suspension is significantly lower than that after application of 0.5% podophyllotoxin alcohol solution, therefore the systemic toxicity may be reduced.