Teniposide Loaded Self-assembly Nanoemulsion：Development And Pharmaceutical Behavior

Teniposide, is a semisynthetic derivative ofpodophllotoxin, with the advantage of anti-tumor broad spectrum and low toxicity. In clinical trials, it has been appl ied to treat many types of cancer such as small cell lung cancer, malignant lymphoma, testicular cancer, acute leukemia and so on. However, Teniposide is practi-cally insoluble in water and extensively metabolized in liver, which results in the incomplete intestinal absorption and very low systemic exposure after oral admini-stration. Moreover, the commercial teniposide injection (Vumon(?)) exhibits some severe adverse effects of myelo-suppression, hypersensitivity reactions and gastrointestinal toxicity in clinical application. Alternatively, oral administration of teniposide may offer an attractive and effective method for the management of cancer. In this work, a teniposide loaded self-assembled nanoemulsion (TSN) was developed to improve the oral bioavailability and tumor targeting of teniposide for further oral chemotherapy.At first, an in vitro RP-HPLC method was established for quantitative determination of Teniposide and quality evaluation of TSN. The linear concentration ranges of calibration curves for Teniposide was0.4～80. Omg. L-1, with good linear relationship. The specificity, precision and recovery was in accordance with analysis requirements. Moreover, The HPLC analysis was also established for determination of gastrointestinal absorption and tissue distribution. The linear concentration ranges of calibration curves for Teniposide was0.1～20.0mg. L-1,with good linear relationship.This method is simple, and the specif-icity, precision and recovery can meet the requirements.At last, HPLC-MS/MS analysis was estabolished for determination of the pharmacokinetic and lymphatic transport, with berberine as an internal standard. In the range of1.00～1000ng. mL-1,linear relationship is good, and the strong specificity, precision, recovery was in line with the requirements.TSN was prepared by film dispersing-hydration method. The involved influence factors such as the drug/chain oil ratio, the TPGS/HS-15ratio, the hydration temperature and the tilt angle of the round bottom flask and the rotation axis while filming were optimized by orthogonal designment with encapsulation efficiency as indexes of evaluation.The encapsulation efficiency of TSN prepared under the optimum formulation was99.25%,and loading efficiency was2.20%. TSN showed a narrow size distribution with the mean particle diameter31.19±4.11nm and a zeta potential of-10.1±0.5mv. The TEM images showed that TSN was almost uniform spheres. TSN remained stable quality before and after freeze-dried. XRD measurements indicated that teniposide was mainly in the molecular state or amorphous state in TSN. The accumulative release of teniposide in artificial intestinal juice was more than in artificial gastric juice. The in vitro Cytotoxicity measurements showed that the antiproliferation activity of teniposide was obviously increased and the cell cycle of MCF-7cells was significantly changed after the treatment of TSN.The absorption and distribution of TSN in the GI tract after oral administration in mice was investigated.The main distri-bution was in the stomach, duodenum and jejunum segments in4h after administration. Moreover, the absorption of TSN was obversed under the laser scanning confocal microscope (LCSM). The experimental results indicated that TSN was mainly absorbed in stomach and proximal intestine, and reduced along the GI tract. The cellular uptake of TSN was performed in Caco-2cell monolayer to elucidate the possible mechanism. The cellular uptake of TSN was increased linearly with the incubation time, which was significantly higher than that of teniposide solution. Moreover, TSN could be internalized into the enterocytes via the clathrin-mediated pathway. The intestinal transport of TSN was measured by a cycloheximide treated model. The measured results indicated that TSN was mainly absorbed into the systemic circulation via the lymphatic transport pathwayThe pharmacokinetics was investigated in SD rats. The tmax and Cmax of TSN was1. Oh and969.0ng. mL-1. The tmax and Cmax of control was0.5h and170.75ng. mL-1. The AUC0-∞(ng. h. mL-1) of TSN increased by about5.47times than that of control. After oral adminis-tration, the teniposide concentration from TSN was maximal in liver and minimal in spleen, which was significantly higher than that of teniposide solution. In tumor bearing mice, the LCSM imgaes indicated TSN could specif ical ly accumulated in tumor and penetrate into the interior site of tumor, which could be benefi-cial to enhancing the antitumor activity of teniposide.