紫杉醇微球-原位凝胶的制备及其局部注射的抗肿瘤药效

Preparation and characterization of paclitaxel microspheres in situ gel and its antitumor efficacy by local injection

目的:为了减少肿瘤治疗的给药次数,降低化疗药物的毒副作用,更好地控制肿瘤进展以及延缓肿瘤术后复发,制备载紫杉醇微球的温敏原位凝胶(temperature-sensitive in situ gel with paclitaxel microspheres,PTX/M gel),以术前瘤旁或术后瘤腔内局部注射的方式给药。方法:首先,通过乳化溶剂挥发法制备紫杉醇微球(paclitaxel microspheres,PTX/M),考察粒径、比表面积、形态、包封率和体外释放特性;其次,通过冷置溶解法制备PTX/M gel,测定相转变温度、弹性模量、溶蚀曲线、溶蚀-释放相关性;最后,分别建立人源U87 MG和鼠源4T1的皮下肿瘤模型,研究PTX/M gel在抑制肿瘤生长、延缓肿瘤复发方面的药效。结果:经筛选,PTX/M中位径为(32.24±1.09)μm,比表面积为(206.61±10.23) m^2 /kg,包封率为85.29%±1.34%,PTX/M中紫杉醇(paclitaxel,PTX)在第30天的累积释放百分率为33.56%±3.33%;PTX/M gel相转变温度为33 ℃,在25 ℃和37 ℃时的弹性模量分别为 4.2× 10^3 Pa和18×10^3 Pa,体内滞留时间可达48 h。动物实验结果显示,与生理盐水组和泰素(Taxol)组相比,PTX/M gel组小鼠的肿瘤生长最缓慢( P <0.05),体内安全性良好,同样地,在肿瘤复发实验中,PTX/M gel组小鼠术后的肿瘤复发时间最晚。结论: PTX/M gel作为一种局部缓释制剂,能有效抑制肿瘤生长,延缓肿瘤术后复发,在肿瘤治疗中具有潜在优势。

Objective: The current difficulties in the treatment of tumor include repeated administration and high recurrence rate after tumor resection. In order to reduce the number of doses, avoid side effects of chemotherapeutic drugs, suppress tumor growth and delay tumor recurrence after surgery, a temperature-sensitive in situ gel with paclitaxel microspheres (PTX/M gel) was prepared. PTX/M gel was administered by intratumoral injection once a month. Methods: First of all, paclitaxel microspheres (PTX/M) were prepared by emulsion solvent evaporation method. A laser particle size distribution analyzer was used to investigate the size, distribution, specific surface area of microspheres. Paclitaxel content was determined by high performance liquid chromatography (HPLC). Then encapsulation efficiency of paclita- xel was calculated and in vitro release characteristics were studied. Secondly, PTX/M gel was prepared by cold dissolution method. The phase transition temperature, elastic modulus, dissolution curve, correlation between dissolution and release were measured. Finally, U87 MG and 4T1 subcutaneous tumor mo- dels were established respectively to study the efficacy of PTX/M gel in suppressing tumor growth and delaying tumor recurrence after surgery. Results: The median diameter of the selected PTX/M was (32.24± 1.09)μm, the specific surface area was (206.61 ±10.23) m^2 /kg, the encapsulation efficiency was 85.29%±1.34%, and the cumulative release percentage of paclitaxel from PTX/M was 33.56%± 3.33% in one month. Phase transition temperature of PTX/M gel was 33 ℃. The elastic modulus of PTX/M gel at 25 ℃ and 37 ℃ were 4.2×10^3 Pa and 18×10^3 Pa, respectively. The gel could stay in the body for up to 48 hours. It could be seen from the results of animal experiments that were compared with the saline group and the Taxol group, and the tumor-bearing mice of the PTX/M gel group had the slowest tumor growth ( P <0.05). Similarly, in the tumor recurrence experiments, the mice of PTX/M gel group had the latest tumor recurrence after surgery. Conclusion: As a local sustained-release preparation, PTX/M gel can effectively suppress tumor growth and delay postoperative recurrence of tumors. It has potential advantages in tumor treatment.