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.

Discovering L-type calcium channels inhibitors of antihypertensive drugs based on drug repositioning / 中国中药杂志

This study was amid to construct the pharmacophore model of L-type calcium channel antagonist in the application of screening Drugbank and TCMD. This paper repositions the approved drugs resulting from virtual screening and discusses the relocation-based drug discovery methods, screening antihypertensive drugs with L-type calcium channel function from TCMD. Qualitative hypotheses wre generated by HipHop separately on the basis of 12 compounds with antagonistic action on L-type calcium channel expressed in rabbit cardiac muscle. Datebase searching method was used to evaluate the generated hypotheses. The optimum hypothesis was used to search Drugbank and TCMD. This paper repositions the approved drugs and evaluates the antihypertensive effect of the chemical constituent of traditional Chinese medicine resulting from virtual screening by the matching score and literature. The results showed that optimum qualitative hypothesis is with six features, which were two hydrogen-bond acceptors, four hydrophobic groups, and the CAI value of 2.78. Screening Drugbank achieves 93 approved drugs. Screening TCMD achieves 285 chemical constituents of traditional Chinese medicine. It was concluded that the hypothesis is reliable and can be used to screen datebase. The approved drugs resulting from virtual screening, such as pravastatin, are potentially L-type calcium channels inhibitors. The chemical constituents of traditional Chinese medicine, such as Arctigenin III and Arctigenin are potentially antihypertensive drugs. It indicates that Drug Repositioning based on hypothesis is possible.