Phenylboronic acid-modified polymaleic anhydride-F127 micelles for pH-activated targeting delivery of doxorubicin.

Phenylboronic acid (PBA) is a tumor-targeting molecule which selectively recognizes sialic acid (SA) overexpressed in tumors. In the study, PBA, F127 and ethanolamine were conjugated with poly(maleic anhydride) by one-step reaction to form amphiphilic polymer for doxorubicin encapsulation. Two drug-carrying micelles with different mass ratio of polymer to drug were prepared by dialysis method to study effect of PBA on doxorubicin release, tumor-targeting and antitumor activity. The study results showed that doxorubicin release from the formulations was acid-sensitive and affected by the polymer dosage, and its acid-induced release behavior improved its insertion into DNA base pairs. Formulation with high polymer dosage showed better tumor targeting and antitumor activity, and activity of inhibiting HepG2 with higher content of SA-containing glycosphingolipids was higher than that of anti-B16. In vivo studies on the activity of B16-bearing mice showed that the doxorubicin-loaded micelles could inhibit the tumor growth and were safer than free doxorubicin. Thus, the PBA-modified nano-polymer micelles have potential biomedical applications due to their nanostructure and tumor-targeting ability.

GKK1032B from endophytic Penicillium citrinum induces the apoptosis of human osteosarcoma MG63 cells through caspase pathway activation.

Chemical investigation of the culture extract of an endophytic Penicillium citrinum from Dendrobium officinale, afforded nine citrinin derivatives (1-9) and one peptide-polyketide hybrid GKK1032B (10). The structures of these compounds were determined by spectroscopic methods. The absolute configurations of 1 and 2 were determined for the first time by calculation of electronic circular dichroism (ECD) data. Among them, GKK1032B (10) showed significant cytotoxicity against human osteosarcoma cell line MG63 with an IC50 value of 3.49 µmol·L-1, and a primary mechanistic study revealed that it induced the apoptosis of MG63 cellsvia caspase pathway activation.

Azithromycin-loaded linolenic acid-modified methoxy poly(ethylene glycol) micelles for bacterial infection treatment.

In the study, new polymeric micelles loaded with azithromycin were prepared to enhance azithromycin's solubility and evaluate its in vitro/in vivo antibacterial activity against Staphylococcus aureus. Amphiphilic α-Linolenic acid-methoxy poly (ethylene glycol) polymer (MPEG-LNA) was synthesized through DCC-DMAP esterification procedure. Through thin-film hydration method, optimized azithromycin-loaded micelles (AZI-M) were prepared with 87.15% of encapsulation efficiency and 11.07% of drug loading capacity when the ratio of LNA to MPEG was 4. Azithromycin's water-solubility was obviously enhanced due to its loading into the polymeric micelles. The azithromycin-loaded micelles were characterized in terms of x-ray diffraction, Fourier transform infrared spectroscopy, in vitro release, and in vitro/in vivo antibacterial experiments. Although the drug-loaded micelles provided a slow and continuous azithromycin's release in comparison with free azithromycin, in vitro antibacterial activity results confirmed that its effect on the inhibition of bacterial growth and biofilm formation was similar to free azithromycin. It is more interesting that the azithromycin-loaded micelles achieved good in vivo antibacterial therapeutic effect like QiXian® (azithromycin lactobionate injection) in mouse model of intraperitoneal infection. AZI-M can be considered as a potential candidate for in vivo antibiotic therapy of Staphylococcus aureus infections.

Paclitaxel skin delivery by micelles-embedded Carbopol 940 hydrogel for local therapy of melanoma.

Local application of anticancer drugs provides a potential mode of chemotherapy for cutaneous melanoma with high compliance. However, the efficiency of drug delivery is highly limited by the physiological barrier from the skin to the tumor, which can not achieve the desired therapeutic effect. In the study, we designed ibuprofen-modified methoxy poly (ethylene glycol)-poly (ethylene imine) polymer to prepare paclitaxel-loaded micelles (PTX-M) and Carbopol 940 hydrogel containing PTX-M (PTX-Gel) to improve skin paclitaxel delivery for the local melanoma treatment. The PTX-M performed well both in the skin penetration and retention study. FT-IR analysis showed that PTX-M or PTX-Gel mainly changed the spatial structure of skin lipid and keratin, thus increasing the fluidity of lipid molecules in the stratum corneum, and the polymer was positively charged to enhance the skin permeation and deposition. Moreover, the positive charge also promoted the cellular uptake of PTX-M in B16 melanoma, resulting in better in vitro cytotoxicity of PTX-M to B16 cells Taxol®. As for in vivo against B16 cells solid tumor test, the Taxol® plus PTX-M/Gel group showed preferable anticancer activity than Taxol® alone.

Recent Development of Copolymeric Nano-Drug Delivery System for Paclitaxel.

BACKGROUND: Paclitaxel (PTX) has been clinically used for several years due to its good therapeutic effect against cancers. Its poor water-solubility, non-selectivity, high cytotoxicity to normal tissue and worse pharmacokinetic property limit its clinical application. OBJECTIVE: To review the recent progress on the PTX delivery systems. METHODS: In recent years, the copolymeric nano-drug delivery systems for PTX are broadly studied. It mainly includes micelles, nanoparticles, liposomes, complexes, prodrugs and hydrogels, etc. They were developed or further modified with target molecules to investigate the release behavior, targeting to tissues, pharmacokinetic property, anticancer activities and bio-safety of PTX. In the review, we will describe and discuss the recent progress on the nano-drug delivery system for PTX since 2011. RESULTS: The water-solubility, selective delivery to cancers, tissue toxicity, controlled release and pharmacokinetic property of PTX are improved by its encapsulation into the nano-drug delivery systems. In addition, its activities against cancer are also comparable or high when compared with the commercial formulation. CONCLUSION: Encapsulating PTX into nano-drug carriers should be helpful to reduce its toxicity to human, keeping or enhancing its activity and improving its pharmacokinetic property.

Phenylboronic acid-functionalized F127-oligochitosan conjugate micelles for doxorubicin encapsulation.

Doxorubicin shows good anticancer activity, but poor pharmacokinetic property and high organ toxicity restrict its clinical application. The synthesized phenylboronic acid-modified F127-chitosan conjugate was used to prepare doxorubicin-loaded micelles through dialysis method. The physicochemical properties of the doxorubicin-loaded micelles were characterized. These micelles were further evaluated for in vitro release/cytotoxicity, in vivo activity/biosafety, and pharmacokinetic studies. in vitro release experiment demonstrated that the release of doxorubicin from drug-loaded micelles was pH-dependent. in vitro cytotoxic study showed that the introduction of phenylboronic acid resulted in lower IC50 against B16 cells than that in non-modified F127-chitosan micelles group, and the doxorubicin-loaded micelles displayed lower in vitro activity against B16, A549, and HT-29 cells than free doxorubicin did. However, in vivo experiments confirmed that the doxorubicin-loaded micelles were safe for mouse main organs, obviously improved pharmacokinetic parameters of doxorubicin in rat and achieved comparable inhibition of tumor growth with no animal death in B16-bearing mice models throughout the experiment when compared with free doxorubicin. The phenylboronic acid-sialic acid interaction and pH-sensitive drug release might play important roles in increased tumor targeting and therapeutic effect of the doxorubicin-loaded micelles.

Linolenic acid-modified MPEG-PEI micelles for encapsulation of amphotericin B.

Aim: To encapsulate amphotericin B (AmB) with reduced toxicity and comparable activity. Results & methodology: The α-linolenic acid (ALA)-modified monomethoxy polyethylene glycol-g-PEI-g-ALA conjugate was employed to prepare AmB-loaded micelles (AmB-M). In vitro activity and release behavior of AmB-M were investigated. AmB-M enhanced AmB's water-solubility to 1.2 mg/ml, showing good storage stability. AmB-M could achieve a sustained and slow release of AmB, low hemolysis activity and negligible kidney toxicity when compared with commercial AmB injection. Antifungal activity and biofilm inhibition experiments confirmed that the antifungal activity of AmB-M against Candida albicans was similar to that of AmB injection. Conclusion: Monomethoxy polyethylene glycol-g-PEI-g-ALA micelles could be a preferable choice to treat systemic fungal infections as an efficient drug delivery system.

Germacrane-type sesquiterpenoids with cytotoxic activity from Sigesbeckia orientalis.

Eleven new highly oxygenated germacrane-type sesquiterpenoids (1-11) and 16 known analogues (12-27) were isolated from the aerial parts of Sigesbeckia orientalis. Their structures, including absolute configurations, were determined by comprehensive spectroscopic methods especially NMR and ECD analyses. Compounds 13, 21 and 23 possessing an 8-methacryloxy group showed stronger in vitro cytotoxicity against human A549 and MDA-MB-231 cancer cell lines than other co-metabolites, with IC50 values ranging from 6.02 to 10.77 µM comparable to the positive control adriamycin.

Transdermal delivery of curcumin-loaded supramolecular hydrogels for dermatitis treatment.

Curcumin (CUR) is a hydrophobic polyphenol with anti-inflammatory activity. However, its low water-solubility and poor skin permeation limited its application in the treatment of dermititis. CUR-loaded micelles were prepared using thin membrane hydration method with methoxy poly (ethylene glycol)-block-poly (ε-caprolactone) (MPEG-PCL) as carrier material. The drug loading capacity and encapsulation efficiency were 12.14 ± 0.33 and 93.57 ± 1.67%, respectively. CUR-loaded micelles increased CUR's water-solubility to 1.87 mg/mL, being 1.87 × 106-folds higher than native CUR. CUR-loaded supramolecular hydrogels (CUR-H) were prepared through mixing the CUR-loaded micelles solution with α-cyclodextrin (α-CD) solution. The CUR-H presented continuous dissolution behaviour in aqueous medium for 4.5 h. The ex vivo skin permeation test and confocal fluorescence microscopy evaluation confirmed that CUR-H obviously enhanced skin deposition of CUR without drug flux from skin. In vivo experimental results confirmed that the CUR-H was more effective than dexamethasone ointments against croton oil-induced ear edema. The CUR-H composed of MPEG-PCL and α-CD is a promising formulation for skin inflammatory treatment.

Linolenic acid-modified methoxy poly (ethylene glycol)-oligochitosan conjugate micelles for encapsulation of amphotericin B.

Introduction of linolenic acid (LNA) and methoxy poly (ethylene glycol) (MPEG) to the backbone of oligochitosan (CS) afforded LNA-modified MPEG-CS conjugate (MPEG-CS-LNA). Amphotericin B-loaded MPEG-CS-LNA micelles (AmB-M) were prepared via dialysis method with 82.27 ± 1.96% of drug encapsulation efficiency and 10.52 ± 0.22% of drug loading capacity. The AmB-M enhanced AmB's water-solubility to 1.64 mg/mL, being 1640-folds higher than native AmB. The AmB-M obviously reduced hemolytic effect and renal toxicity of AmB when compared to marketed AmB injection (AmB-I). Its antifungal activity against Candida albicans was equivalent to AmB-I although AmB's release from AmB-M was significantly retarded. According to fluorescence microscopy test, the unchanged activity should be attributed to enhanced fungal cellular uptake of AmB-M caused by combined inducement of LNA and CS. The pharmacokinetic studies demonstrated that AmB-M also improved the pharmacokinetic parameters of AmB with AmB-I as control. Conclusively, developed LNA-modified MPEG-CS micellar system could be a viable alternative to the current toxic commercial AmB-I as a highly efficacious drug delivery system.

A novel curcumin-loaded nanoparticle restricts atherosclerosis development and promotes plaques stability in apolipoprotein E deficient mice.

Although curcumin possesses anti-atherogenic and anti-inflammatory properties, its application is limited because of its low aqueous solubility and poor oral bioavailability. Recently, our group synthesized a novel linear-dendrimer methoxy-poly (ethylene glycol)-b-poly(ε-caprolactone) copolymer nanoparticle loading curcumin (Cur-NPs) which could improve solubility and release property of curcumin. In the present study, we further evaluated its anti-atherosclerotic effect in apolipoprotein E-/- mice. Our results demonstrated that the Cur-NPs significantly decreased atherosclerotic lesion areas and were more effective in stabilizing vulnerable plaques compared with free curcumin. The anti-atherosclerotic mechanisms of Cur-NPs include decreasing the number of introplaque microvessels, inhibiting the matrix metalloproteinase 2 and 9 activity, reducing the inflammatory response and regulating lipoprotein cholesterol metabolism more effectively compared with free curcumin. Furthermore, Cur-NPs could increase the amount of curcumin in the thoracic aorta and no significant toxicity was observed in the blood biochemical parameters in Cur-NPs-treated groups. Overall, our findings suggested that Cur-NPs could be a stabilized aqueous formulation for application with improved curcumin activity, which could be a potential treatment strategy for arteriosclerosis in the future.

Itraconazole-loaded micelles based on linear-dendritic poly (ethylene glycol)-b-poly (ε-caprolactone).

A copolymeric micelle formulation of itraconazole (ITR-M) was prepared using linear-dendritic monoallyloxy poly (ethylene glycol)-b-poly (ε-caprolactone) (APEG-PCL) as drug carrier materials. DL and EE values of ITR-M were 5.70 ± 0.12% and 91.30 ± 1.90%, respectively. The micelle formulation enhanced the ITR solubility up to 30.42 µg/mL. In vitro release of ITR from the ITR-M was mainly drug diffusion process followed by the copolymer's degradation. ITR-M showed similar anti-Candida albicans activity to that of crude ITR although its release of ITR was slow and continuous. The in vivo pharmacokinetic study demonstrated that the ITR-M could improve tissue distribution of ITR. In conclusion, APEG-PCL could be a potential carrier in the development of antifungal drug delivery system.

MPEG-PCL Copolymeric Micelles for Encapsulation of Azithromycin.

Macrolide antibiotics are lipophilic drugs with some limitations including low solubility, limited cellular permeation, patients discomfort, etc. With amphiphilic methoxy poly(ethylene glycol)-b-poly(ε-caprolactone) (MPEG-PCL) copolymer and azithromycin (AZT) as drug carrier and model drug, AZT-loaded micelles were prepared via thin-membrane hydration method in order to overcome these limitations. Encapsulation efficiency of AZT-loaded micelles was 94.40% with good storage stability for 28 days, and AZT's water solubility was enhanced to 944 µg/mL. Fourier transform infrared spectrum and x-ray diffraction analysis indicated that AZT was enveloped into the micelles in amorphous form due to its interaction with the copolymer. AZT's in vitro release from the AZT-loaded micelles demonstrated a slow and continuous behavior when compared with raw AZT. The release dynamics was accorded with Weibull equation, meaning that release amount of AZT lowered with time and was proportional to remaining amount of drug in the AZT-loaded micelles. Korsmeyer-Peppas fitting result suggested that drug release process was a classical Fickian diffusion-controlled manner. With Staphylococcus aureus as bacterial strain, antibacterial activity of the AZT-loaded micelles displayed was comparable with raw AZT. In conclusion, MPEG-PCL should be a promising carrier for macrolide antibiotic delivery in treatment of bacterial infections.

Oligochitosan-pluronic 127 conjugate for delivery of honokiol.

Honokiol-loaded micelles were prepared by emulsion-solvent evaporation procedure when oligochitosan-pluronic conjugate (CS-F127) as carrier. Differential scanning calorimetry (DSC) indicated that honokiol existed in amorphous form when it was encapsulated into the micelles with 87.54 ± 1.52% of encapsulation efficiency (EE) and 12.51 ± 0.22% of drug loading (DL) capacity. The water-solubility was increased to 1.46 mg/mL, being >27-folds higher than pure honokiol. The in vitro release study demonstrated a slow and sustained ± release of honokiol from the drug-loaded micelles with pure honokiol as control. The in vitro antifungal and cellular uptake tests indicated that the drug-loaded micelles showed the same activity as pure honokiol against Candida albicans due to its good cellular uptake although it slowly released honokiol. The pharmacokinetic test results showed that the honokiol-loaded micelles increased area under curves and mean retention time of honokiol with low clearance rate and apparent distribution volume when compared with pure honokiol, showing its ability to improve honokiol's pharmacokinetic properties. The honokiol-loaded micelles also showed good bio-security to normal cells and main organs of mice. In conclusion, the CS-F127 conjugate should be a potential carrier for honokiol or other antifungal agents in the treatment of fungal infections.

Recent Progress of Nano-drug Delivery System for Liver Cancer Treatment.

Liver cancer is one of serious diseases which threaten human life and health. Studies on the treatment of liver cancer have attracted widespread attention. Application of nano-drug delivery system (NDDS) can not only improve selective drug delivery to liver tissue and improve the bioavailability of drug, but also can reduce the side effects of drugs when it is specially modified in the respects of structure modification or specific target molecules decoration. This review will address the latest development of liver-targeted drug delivery system.

Y-shaped methoxy poly (ethylene glycol)-block-poly (epsilon-caprolactone)-based micelles for skin delivery of ketoconazole: in vitro study and in vivo evaluation.

Ketoconazole is a hydrophobic broad-spectrum antifungal agent for skin infection therapy. In order to develop topical formulation of ketoconazole for improving its selective skin deposition and water-solubility, ketoconazole-loaded Y-shaped monomethoxy poly(ethylene glycol)-block-poly(ɛ-caprolactone) micelles were prepared through thin-film hydration method with high entrapment efficiency (96.1±0.76%) and small particle (about 58.66nm). The drug-loaded micelles showed comparative in vitro antimicrobial activity with KET cream. In ex in vivo skin deposition and permeation study, ketoconazole-loaded micelles provided skin accumulation higher than marketed ketoconazole cream without obvious permeation in the whole period. Fluorescence microscopy study and histopathological study demonstrated the copolymeric micelles' penetrating into skin in depth due to its capability of weakening the barrier function of stratum corneum. In vivo skin deposition parameters further confirmed high skin deposition of drug-loaded micelles (AUC(0-t)=396.16µg·h/cm2) over marketed ketoconazole cream (AUC(0-t)=250.03µg·h/cm2). Meanwhile, in vivo pharmacokinetic parameters proved that ketoconazole-loaded micelles reduced ketoconazole's distribution in blood in comparison with the cream (AUC(0-t)=93,028.00µg·h/L vs AUC(0-t)=151,714.00µg·h/L), meaning lower possibility of its systemic unwanted effects in the skin fungal infection treatment. The results suggested that the copolymeric micelles can be adopted for specific delivering ketoconazole into skin for fungal infection cure.

In vitro characterization of pH-sensitive azithromycin-loaded methoxy poly (ethylene glycol)-block-poly (aspartic acid-graft-imidazole) micelles.

In order to improve azithromycin's antibacterial activity in acidic medium, monomethoxy poly (ethylene glycol)-block-poly (aspartic acid-graft-imidazole) copolymer was synthesized through allylation, free radical addition, ring-opening polymerization and amidation reactions with methoxy poly (ethylene glycol) as raw material. Drug loading capacity and encapsulation efficiency of azithromycin-loaded micelles prepared via thin film hydration method were 11.58±0.86% and 96.06±1.93%, respectively. The drug-loaded micelles showed pH-dependent property in the respects of particle size, zeta potential at the range of pH 5.5-7.8. It could control drug in vitro release and demonstrate higher release rate at pH 6.0 than that at pH 7.4. In vitro antibacterial experiment indicated that the activity of azithromycin-loaded micelles against S. aureus was superior to free azithromycin in medium at both pH 6.0 and pH 7.4. Using fluorescein as substitute with pH-dependent fluorescence decrease property, laser confocal fluorescence microscopy analysis confirmed that cellular uptake of micelles was improved due to protonation of copolymer's imidazole groups at pH 6.0. The enhanced cellular uptake and release of drug caused its activity enhancement in acidic medium when compared with free drug. The micellar drug delivery system should be potential application in the field of bacterial infection treatment.

Enhanced effect in combination of curcumin- and ketoconazole-loaded methoxy poly (ethylene glycol)-poly (ε-caprolactone) micelles.

In order to enhance water-solubility and realize controlled release while keeping synergistic effects of ketoconazole and curcumin, drug-loaded methoxy poly (ethylene glycol)-b-poly (ε-caprolactone) micelles were prepared through thin membrane hydration method. Transmission electric microscopy and dynamitic light scattering characterization revealed the formation of ketoconazole- and curcumin-loaded micelles with an average size of 44.70nm and 39.56nm, respectively. The drug-loaded micelles endowed the two drugs' slow controlled release with water-solubility enhanced to 85 and 82000 folds higher than the corresponding raw drugs, respectively. In vitro antifungal activity test, chequerboard test and inhibition zone test indicated that efficacy of ketoconazole-loaded micelles was improved by introduction of curcumin-loaded micelles with a low fractional inhibitory concentration index (0.073). Biofilm formation inhibition assay also demonstrated that participation of curcumin-loaded micelles obviously strengthened the inhibition of fungal biofilms formation induced by ketoconazole-loaded micelles. The high synergistic activity of combinations is encouraging and the MPEG-PCL micelle is a potential drug delivery system for the combination of ketoconazole and curcumin.

Y-shaped Folic Acid-Conjugated PEG-PCL Copolymeric Micelles for Delivery of Curcumin.

BACKGROUND: Curcumin is a natural hydrophobic product showing anticancer activity. Many studies show its potential use in the field of cancer treatment due to its safety and efficiency. However, its application is limited due to its low water-solubility and poor selective delivery to cancer. OBJECTIVE: A Y-shaped folic acid-modified poly (ethylene glycol)-b-poly (ε-caprolactone)2 copolymer was prepared to improve curcumin solubility and realize its selective delivery to cancer. METHOD AND RESULTS: The copolymer was synthesized through selective acylation reaction of folic acid with α- monoamino poly(ethylene glycol)-b-poly(ε-caprolactone)2. Curcumin was encapsulated into the copolymeric micelles with 93.71% of encapsulation efficiency and 11.94 % of loading capacity. The results from confocal microscopy and cellular uptake tests showed that folic acid-modified copolymeric micelles could improve cellular uptake of curcumin in Hela and HepG2 cells compared with folic acid-unmodified micelles. In vitro cytotoxicity assay showed that folic acid-modified micelles improved anticancer activity against Hela and HepG2 cells in comparison to folic acidunmodified micelles. Meanwhile, both drug-loaded micelles demonstrated higher activity against Hela cell lines than HepG2. CONCLUSION: The research results suggested that the folic acid-modified Y-shaped copolymeric micelles should be used to enhance hydrophobic anticancer drugs' solubility and their specific delivery to folic acid receptors-overexpressed cancer.

Methoxy poly (ethylene glycol)-b-poly (δ-valerolactone) copolymeric micelles for improved skin delivery of ketoconazole.

Ketoconazole is a broad spectrum imidazole antifungal drug. For the treatment of superficial fungal infections with ketoconazole, it needs to be permeated to deep skin layers. In order to develop topical formulation of ketoconazole for improving its skin deposition and water-solubility, ketoconazole-loaded methoxy poly (ethylene glycol)-b-poly (δ-valerolactone) micelles were developed through thin-film hydration method. Particle size, drug loading capacity, infrared spectrum and X-ray diffraction of drug-loaded micelles were characterized. The optimal drug formulation was selected for skin delivery and deposition investigation performed by use of mice skin, and its in vitro release and antifungal activity were also investigated. Penetration and distribution in the skin were also visualized using fluorescein-loaded micelles and fluorescence microscopy. The drug-loaded micelles were obtained with encapsulation efficiency of 86.39% and particle diameter of about 12 nm. The micelles made ketoconazole aqueous solubility increase to 86-fold higher than crude one. Ketoconazole-loaded micelles showed no skin permeation of ketoconazole, obviously enhance skin deposition and demonstrated similar antifungal activity as compared with marketed ketoconazole cream. Fluorescein-loaded micelles displayed higher skin deposition than fluorescein water solution. These results demonstrate that the MPEG-PVL micelle is a potential delivery system for ketoconazole in the field of skin delivery.