Preformulation And Lipsome Preparation Studies On A Novel Derivative Of Podophyllotoxin

Podophyllotoxin as well as its derivatives exhibit pronounced biological activity mainly as strong anti-tumor and antiviral agents, which is a good source of the arylteralin-type lignan. Some effect anti-tumor agents have been found, however, there are some problems such as acquired drug-resistance, poor water-solubility, severe bone marrow depression and poor efficacy for oral use in studies of podophyllotoxin derivatives. 5-Fluorouracil (5-FU), as one of the major antimctabolic anticancer agent, was used clinically with many anti-tumor drug to prove therapeutic efficacy, however, there are the less bioavailability and high toxic action side effect, too. So Podophyllotoxin and 5-Fluorouracil as lead compound were carried out structural modification and optimize to obtain the better anti-tumor drug with high activities and less toxic. 5-Fluorourcial-acetic podophyllic ester (5-FPE) is a new synthesized derivative of podophyllotoxin followed the 'association principle' in medicinal chemistry. And its inhibition activity in vitro was stronger than VP-16 and 5-FU. Therefore, 5-FPE was carried out the further study.Firstly, studies were carried out on the physico-chemical property and stabilities of 5-FPE. Its melting point, specific rotary power, partition coefficients and purity were 178 - 180℃, -58.4°, 0.51 and 99.35% , respectively. Its solubility in acetone, acetoacetate and acetonitrile was better than in methanol, chloroform and ethanol. The solubility in water and propylene glycol was poor. High performance liquid chromatographic method was used to determine the content of 5-FPE. 10μL of tested solution was injected onto a Kromasil 100 A C₁₈ column (350 mm×4.6 mm, 5μm) and chromatographed with methanol/water (V/V:58:42) as mobile phase. The detecter UV wavelength was 271 nm. Its stabilities in different conditions were also investigated. In solid-state it was stable at 60℃and 4500 lx light in 10 days. However, it was less stable under the condition of 75% relative humidity (RH) at 25℃. It was more stable in methanol (4℃) and chloroform (25℃) than in methanol (25℃). It was unstable in artificial gastric juice and artificial intestinal juice (37℃). Its stabilities in various buffer solutions were decreased while increasing the pH of buffer solutions.Furtherly, studies were carried out on the acute toxicity and anti-tumor activity in vivo of 5-FPE. The acute toxicity of 5-FPE was much weaker than VP-16 and 5-FU, but its inhibility on the growth of S180 was slightly lower than VP-16 and 5-FU.To improve water-solubility and stabilities of 5-FPE studies also were carried out on preparation and characterization of 5-FPE lipsome. A thin hydration-sonication method was used to prepare 5-FPE lipsome. Orthogonal experimental design was used to choose the optimal condition of 5-FPE lipsome preparation with the entrapment efficiency as the evaluation quota. The best craft of 5-FPE liposome preparation was that the rotary evaporating temperature is set at 50℃, the volume of PBS was 4mL, the ultrasonic power was 100 % and the ultrasonic time was 10 min. And the best prescription is that 5-FPE : CH was 3 : 5, SPC : CH was 4 : 1, the pH of PBS was 7.0 and the volume of chloroform was 2mL. The free drug and liposome were separated by high speed centrifugation, and then the entrapment efficiency was determined by high performance liquid chromatogram. Average entrapment efficiency of the 5-FPE lipsome was 66.45%. average diameter was 284.7nm, and average Zeta potential was -22.15mV. The anti-tumor activity study showed that the 5-FPE liposome can inhibit the growth of S180 in vivo. However, its anti-tumor activity was slightly lower than VP-16 and 5-FU.