pH and GSH dual-responsive silybin nano-micelles for inhibition of breast cancer activity and metastasis in vitro / 药学学报

The clinical tumor therapy was greatly challenged due to the complex characteristics of tumor microenvironment, however, which also provide arena for novel therapeutic strategies. In this study, poly(2-ethyl-2-oxazoline)-poly(lactic acid)-SS-poly(β-amino ester (PEOz-PLA-SS-PBAE) triblock copolymers with pH and GSH double response were synthesized, polymer micelles were prepared by thin film hydration method for loading of silybin to improve its antitumor activity. The critical micelle concentration was determined by pyrene fluorescence method as 1.8 μg·mL-1. The particle size was 155.30 ± 1.80 nm as determined by dynamic light scattering, with polydispersity index of 0.168 ± 0.004. The drug loading and entrapment efficiency of the micelles were determined by HPLC as (5.48 ± 0.04)% and (68.52 ± 0.48)%, respectively. The in vitro drug release profiles showed that the micelles have low pH sensitivity and high GSH responsiveness, and exhibited sustained release profiles. The good biocompatibility of the material was proved by measuring the hemolysis rate and cytotoxicity of the blank micelle. The cytotoxicity and apoptosis rate of tumor cells showed that the drug loaded PEOz-PLA-SS-PBAE micelles had significant inhibitory effect and apoptosis-inducing effect on MDA-MB-231 cells. The results of wounding healing assay and Transwell invasion test showed that the drug loaded PEOz-PLA-SS-PBAE micelles could significantly inhibit the metastasis of MDA-MB-231 cells. The PEOz-PLA-SS-PBAE drug-loaded micelles prepared in this study have good inhibitory effect on tumor growth and anti-tumor metastasis in vitro, which lays the foundation for the further application of silybin.

pH responsive docetaxel micelles with improved therapeutic efficacy on mice xenograft tumor / 药学学报

The non-specific administration of antitumor drugs is the main cause for the side effects of chemotherapy drugs on normal tissues. The application of nanotechnology in the delivery of anti-tumor drugs is one of the important ways to improve the therapeutic effect and to reduce the side effects. The current study aimed to synthesize pH responsive poly (methoxy-ethylene glycol)-poly(lactic acid)-poly-(β-amino ester) (PBAE) triblock copolymers to deliver docetaxel (DTX) and improve the anti-tumor activity of DTX. PBAE was synthesized by ring opening polymerization and Michael addition reaction, its structure and molecular weight was characterized by 1H NMR, the dissociation constant of base (pKb) were determined by acid-base titration method. The critical micelles concentration (CMC) of copolymers was measured by pyrene fluorescence spectroscopy. DTX loaded copolymer micelles were prepared by membrane hydration method. The size and its distribution as well as the stability of micelles were determined by laser light scattering analysis. The drug loading content (DL), entrapment efficiency (EE) and cumulative drug release from micelles were evaluated by high-performance liquid chromatography (HPLC). The sizes of DTX drug-loaded micelles were in the range of 10 to 100 nm with narrow distribution. DL of DTX in PBAE1 and PBAE2 micelles was (5.3 ± 0.10) % and (4.9 ± 0.05) %, respectively, with EE was (93.8 ± 1.70) % and (87.2 ± 4.10) %, respectively. The drug-loaded micelles showed pH sensitive drug release properties under weak acidic conditions, which showed potential drug release of DTX under mild acidic tumor environment. A mouse Lewis lung carcinoma model was established to evaluate the therapeutic efficacy of micellar DTX formulations. Significant inhibitory effect of the nanodrugs was observed with DTX dosages of 10 and 20 mg·kg-1, respectively. Moreover, the pH responsive PBAE1-DTX micellar drug exhibited stronger therapeutic efficacy on mice xenograft tumor, as compared with the non pH sensitive micellar drug (PELA-DTX) and free DTX. All animal experiments were performed according to the animal ethical standards and approved by the Animal Experiments and Ethical Committee of China Academy of Chinese Medical Sciences (No. 2017090110). The in vivo anti-tumor activity studies showed that the tumor volume growth rates of mice in different drug-administered groups were: PBAE1-DTX 20 mg·kg-1 < PBAE1-DTX 10 mg·kg-1 < PELA-DTX 10 mg·kg-1 < DTX 10 mg·kg-1 < normal saline, with the PBAE1-DTX group as the most potent group for tumor inhibition. The current pH sensitive DTX nano-micelles showed high potential in further studies to promote the application of nano DTX formulations for tumor treatment.

Preparation of docetaxel-loaded nanomicelles and their anti-Lewis lung cancer effect in vitro / 中国中药杂志

Docetaxel-loaded nanomicelles were prepared in this study to improve the solubility and tumor targeting effect of docetaxel(DTX),and further evaluate their anticancer effects in vitro. PBAE-DTX nanomicelles were prepared by film-hydration method with amphiphilic block copolymer polyethyleneglycol methoxy-polylactide(PELA) and pH sensitive triblock copolymer polyethyleneglycol methoxy-polylactide-poly-β-aminoester(PBAE) were used respectively to prepare PELA-DTX nanomicelles and PBAE-DTX nanomicelles. The nanomicelles were characterized by physicochemical properties and the activity of mice Lewis lung cancer cells was studied. The results of particle size measurement showed that the blank micelles and drug-loaded micelles had similar particle sizes, ranging from 10 to 100 nm. The particle size of PBAE micelles was changed under weak acidic conditions, with good pH response. The encapsulation efficiency of the above two types of DTX-loaded nanomicelles determined by HPLC was(93.8±1.70)% and(87.2±4.10)%, and the drug loading amount was(5.3±0.10)% and(4.9±0.05)%,respectively. Furthermore,the DTX micelles also showed significant inhibitory effects on Lewis lung cancer cells by MTT assay, and pH-sensitive PBAE-DTX showed better cytotoxicity. The results of flow cytometry indicated that,the apoptosis rate of lung cancer Lewis cells was(20.72±1.47)%,(29.71±2.38)%,and(40.91±1.90)%(P<0.05) at 48 h after treatment in DTX,PELA-DTX,and PBAE-DTX groups. The results showed that different docetaxel preparations could promote the apoptosis of Lewis cells, and PBAE-DTX had stronger apoptotic-promoting effect. The pH-sensitive DTX-loaded micelles are promising candidates in developing stimuli triggered drug delivery systems in acidic tumor micro-environments with improved inhibitory effects of tumor growth on Lewis lung cancer.

Pharmacokinetics and Tumor Tissue Distribution of Docetaxel Nanomicelles in Mice / 中国实验方剂学杂志

Objective: To investigate the pharmacokinetics and the distribution in tumor tissues of docetaxel nanomicelles. Method: The docetaxel nanomicelles was prepared by filming-rehydration method.HPLC was employed to determine the content of docetaxel in biological samples and the corresponding methodological evaluation was carried out.The mouse Lewis lung carcinoma model was established,when dosage of administration in tail vein was 20 mg·kg-1,and then the effect of free drug(DTX),non-pH-sensitive drug-loaded micelles(PELA-DTX) and pH-sensitive drug-loaded micelles(PBAE-DTX) on the pharmacokinetics and tissue distribution of tumor-bearing mice were investigated. Result: The docetaxel nanomicelles(PELA-DTX and PBAE-DTX) were successfully prepared.The method for the determination of docetaxel in mice was established by HPLC,the linearity,precision of the method and the recovery rate of samples all met the requirements.In the pharmacokinetic study,the plasma concentration of PBAE-DTX was always at a high level within 24 h.Compared with PELA-DTX and DTX,the areas under the curve(AUC0-∞) of PBAE-DTX were increased by 3.63% and 8.96%,the mean residence times(MRT) were extended by 2.86% and 6.43%,the half-life and the drug blood circulation time were prolonged.In the tissue distribution study,it was found that three docetaxel preparations were distributed in the heart,liver,spleen,lung,kidney and tumor tissue within 1 h after administration,but the distribution of these drugs in the tissues was reduced along with the extension of time,the accumulation of PBAE-DTX in tumor tissue was significantly higher than that in DTX and PELA-DTX at 24 h. Conclusion: PBAE-DTX can prolong the circulation time of docetaxel in the blood,increase its bioavailability,and significantly increase its distribution in tumor tissue.