Preparation, stability and pharmacokinetics evaluation of lipid microspheres loading a promising antitumor candidate, Timataxel

Preparation of mPEG-b-PLA/TM-2 Micelle Lyophilized Products by Mixed Lyoprotectors and Antitumor Effect In Vivo

The objective of this study was to encapsulate the poorly water-soluble drug TM-2 into polymer micelles using mPEG_2k-b-PLA_2.4k to increase its aqueous solubility and improve its therapeutic effect for liver cancer. Furthermore, in order to achieve long-term storage, the micelle solution was successfully freeze-dried. This study theoretically clarified the possibility of enhancing the water solubility of TM-2 using mPEG_2k-b-PLA_2.4k micelles as well as the protective effects of mixed lyoprotectants. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were performed, which showed that the drug has a good affinity with the polymer (χ = 0.489) according to Flory-Huggins theory and that lyoprotectants reduced the crystallinity of PEG in mPEG_2k-b-PLA_2.4k and played a space-protective role in the lyophilization process. In vivo experiments showed that micellization could improve the drug bioavailability and give a high therapeutic effect with a tumor inhibition rate of 84.5% under the tolerated dose.

Drug-Polymer Interaction, Pharmacokinetics and Antitumor Effect of PEG-PLA/Taxane Derivative TM-2 Micelles for Intravenous Drug Delivery

PURPOSE

A novel polymer micelle was prepared with a high drug loading, good stability, high tolerance and better anti-tumor effect.

METHODS

TM-2 was encapsulated in poly-block-poly (D, L-lactic acid) self-assembled micelles by the thin-film hydration method. From the critical micelle concentrations of the copolymers, particle size, drug loading and encapsulation efficiency of drug-loading micelles, the appropriate polymer material could be assessed. Comparisons between TM-2 solution and TM-2 micelles were done to evaluate the pharmacokinetics and toxicity in rats, compared with Taxol to evaluate the anti-tumor effect in mice.

RESULTS

The optimized TM-2 micelles achieved a high drug loading (~20%) with the polymer material of PEG_2k-PLA_2.5k, with a particle size of 30 nm and no significant change in particle size after lyophilization. The result of pharmacokinetic experiment displayed that the half-life in vivo was obviously prolonged. The maximum tolerated dose of TM-2 micelles was approximately 25 mg/kg in rats, and the relative tumor growth rate of Taxol (15 mg/kg), TM-2 (10 mg/kg), TM-2 (15 mg/kg) and TM-2 (40 mg/kg) in mice were 49.35%, 49.14%, 36.44 and 9.98% respectively.

CONCLUSIONS

TM-2 micelles with high drug loading increased drug solubility, improved tolerance, antitumor effects and reduced toxicity.