Chitosan-dextran sulphate nanocapsule drug delivery system as an effective therapeutic against intraphagosomal pathogen Salmonella

Objectives: The ability to target conventional drugs efficiently inside cells to kill intraphagosomal bacteria has been a major hurdle in treatment of infective diseases. We aimed to develop an efficient drug delivery system for combating infection caused by Salmonella, a well-known intracellular and intraphagosomal pathogen. Chitosan dextran sulphate (CD) nanocapsules were assessed for their efficiency in delivering drugs against Salmonella. Methods: The CD nanocapsules were prepared using the layer-by-layer method and loaded with ciprofloxacin or ceftriaxone. Antibiotic-loaded nanocapsules were analysed in vitro for their ability to enter epithelial and macrophage cells to kill Salmonella. In vivo pharmacokinetics and organ distribution studies were performed to check the efficiency of the delivery system. The in vivo antibacterial activity of free antibiotic and antibiotic loaded into nanocapsules was tested in a murine salmonellosis model. Results: In vitro and in vivo experiments showed that this delivery system can be used effectively to clear Salmonella infection, CD nanocapsules were successfully employed for efficient targeting and killing of the intracellular pathogen at a dosage significantly lower than that of the free antibiotic. The increased retention time of ciprofloxacin in the blood and organs when it was delivered by CD nanocapsules compared with the conventional routes of administration may be the reason underlying the requirement for a reduced dosage and frequency of antibiotic administration. Conclusions: CD nanocapsules can be used as an efficient drug delivery system to treat intraphagosomal pathogens, especially Salmonella infection, This delivery system might be used effectively for other vacuolar pathogens including Mycobacteria, Brucella and Legionella.

Chitosan-dextran sulphate nanocapsule drug delivery system as an effective therapeutic against intraphagosomal pathogen Salmonella

Objectives: The ability to target conventional drugs efficiently inside cells to kill intraphagosomal bacteria has been a major hurdle in treatment of infective diseases. We aimed to develop an efficient drug delivery system for combating infection caused by Salmonella, a well-known intracellular and intraphagosomal pathogen. Chitosan dextran sulphate (CD) nanocapsules were assessed for their efficiency in delivering drugs against Salmonella. Methods: The CD nanocapsules were prepared using the layer-by-layer method and loaded with ciprofloxacin or ceftriaxone. Antibiotic-loaded nanocapsules were analysed in vitro for their ability to enter epithelial and macrophage cells to kill Salmonella. In vivo pharmacokinetics and organ distribution studies were performed to check the efficiency of the delivery system. The in vivo antibacterial activity of free antibiotic and antibiotic loaded into nanocapsules was tested in a murine salmonellosis model. Results: In vitro and in vivo experiments showed that this delivery system can be used effectively to clear Salmonella infection, CD nanocapsules were successfully employed for efficient targeting and killing of the intracellular pathogen at a dosage significantly lower than that of the free antibiotic. The increased retention time of ciprofloxacin in the blood and organs when it was delivered by CD nanocapsules compared with the conventional routes of administration may be the reason underlying the requirement for a reduced dosage and frequency of antibiotic administration. Conclusions: CD nanocapsules can be used as an efficient drug delivery system to treat intraphagosomal pathogens, especially Salmonella infection, This delivery system might be used effectively for other vacuolar pathogens including Mycobacteria, Brucella and Legionella.

Safe lipid nanocapsule-based gel technology to target lymph nodes and combat mediastinal metastases from an orthotopic non-small-cell lung cancer model in SCID-CB17 mice

International audience

Intracellular delivery of doxorubicin encapsulated in novel pH-responsive chitosan/heparin nanocapsules

A novel polyelectrolyte nanocapsule system composed of biopolymers, chitosan and heparin has been fabricated by the layer-by-layer technique on silica nanoparticles followed by dissolution of the silica core. The nanocapsules were of the size range 200 +/- 20 nm and loaded with the positively charged anticancer drug doxorubicin with an efficiency of 89%. The loading of the drug into the capsule happens by virtue of the pH-responsive property of the capsule wall, which is determined by the pKa of the polyelectrolytes. As the pH is varied, about 64% of the drug is released in acidic pH while 77% is released in neutral pH. The biocompatibility, efficiency of drug loading, and enhanced bioavailability of the capsule system was confirmed by MTT assay and in vivo biodistribution studies.

Dual enzyme responsive and targeted nanocapsules for intracellular delivery of anticancer agents

We report the fabrication of dual enzyme responsive hollow nanocapsules which can be targeted to deliver anticancer agents specifically inside cancer cells. The enzyme responsive elements, integrated in the nanocapsule walls, undergo degradation in the presence of either trypsin or hyaluronidase leading to the release of encapsulated drug molecules. These nanocapsules, which were crosslinked and functionalised with folic acid, showed minimal drug leakage when kept in pH 7.4 PBS buffer, but released the drug molecules at a rapid rate in the presence of either one of the triggering enzymes. Studies on cellular interactions of these nanocapsules revealed that doxorubicin loaded nanocapsules were taken up by cervical cancer cells via folic acid receptor medicated endocytosis. Interestingly the nanocapsules were able to disintegrate inside the cancer cells and release doxorubicin which then migrated into the nucleus to induce cell death. This study indicates that these nanocapsules fabricated from biopolymers can serve as an excellent platform for targeted intracellular drug delivery to cancer cells.

Protamine-carboxymethyl cellulose magnetic nanocapsules for enhanced delivery of anticancer drugs against drug resistant cancers

Multidrug resistance is a major therapeutic challenge faced in the conventional chemotherapy. Nanocarriers are beneficial in the transport of chemotherapeutics by their ability to bypass the P-gp efflux in cancers. Most of the P-gp inhibitors under phase II clinical trial are facing failures and hence there is a need to develop a suitable carrier to address P-gp efflux in cancer therapy. Herein, we prepared novel protamine and carboxymethyl cellulose polyelectrolyte multi-layered nanocapsules modified with Fe3O4 nanoparticles for the delivery of doxorubicin against highly drug resistant HeLa cells. The experimental results revealed that improved cellular uptake, enhanced drug intensity profile with greater percentage of apoptotic cells was attained when doxorubicin loaded magnetic nanocapsules were used in the presence of external magnetic field. Hence, we conclude that this magnetic field assisted nanocapsule system can be used for delivery of chemotherapeutics for potential therapeutic efficacy at minimal dose in multidrug resistant cancers. From the Clinical Editor: Many cancer drugs fail when cancer cells become drug resistant. Indeed, multidrug resistance (MDR) is a major therapeutic challenge. One way that tumor cells attain MDR is by over expression of molecular pumps comprising of P-glycoprotein (P-gp) and multidrug resistant proteins (MRP), which can expel chemotherapeutic drugs out of the cells. In this study, the authors prepared novel protamine and carboxymethyl cellulose polyelectrolyte multi-layered nanocapsules modified with Fe3O4 nanoparticles for the delivery of doxorubicin. The results show that there was better drug delivery and efficacy even against MDR tumor cells. (C) 2015 Elsevier Inc. All rights reserved.

中药蜘蛛香的化学成分研究及以羧甲基魔芋葡苷聚糖-壳聚糖为细胞膜的天冬酰胺酶人工细胞研究

本论文由三章组成。第一章介绍了中药蜘蛛香的化学成分的研究成果，第二章为羧甲基魔芋葡苷聚糖-壳聚糖为细胞膜的天冬酰胺酶人工细胞的研究，第三章综述了人工细胞在生物医学领域的应用。 第一章报道了中药蜘蛛香（Valeriana wallichii）根部乙醇提取物的化学成分，采用正、反相硅胶层析等分离方法和MS、NMR等多种波谱手段，从中共分离鉴定出17个化合物，分别为缬草素(valtrate，1)，valechlorine（2），homobadrinal（3），baldrinal（4），乙酰缬草素(acevaltrate 5)，valeriotetrate C（6），valeriotetrate B（7），对羟基苯乙酮(4'-hydroxy-acetophenone 8)，7-hydroxy valtrate（9），8-methylvalepotriate（10），1,5-dihydroxy-3,8-epoxyvalechlorine A（11），二氢缬草素(didrovaltrate 12)，胡萝卜苷（13），橙皮苷 (hesperidin 14)，prinsepiol-4-O-β-D-glucopyranoside（15），longiflorone（16），乙基糖苷（17）。其中化合物6、7、10、和11为新化合物，化合物9、15、16为首次从该植物中得到。新化合物11为含有氯原子的刚性骨架环烯醚萜，并且确定了其绝对构型。 第二章报道了以羧甲基魔芋葡苷聚糖（CKGM）和壳聚糖（CS）为膜的固定化L-天冬酰胺酶人工细胞研究成果。利用羧甲基魔芋葡苷聚糖和壳聚糖两种生物相容性很好的天然多糖之间的静电吸引力，在非常温和的条件下制备成具有半透过性膜的人工细胞，将治疗儿童急性成淋巴细胞性白血病(ALL)的药物L-天冬酰胺酶包裹在内。通过考察温度和pH对人工细胞的影响,结果表明以CKGM- CS为膜的L-天冬酰胺酶人工细胞对温度和pH的稳定性和耐受性均高于自由酶，说明CKGM-CS对酶具有保护作用，而且小分子底物和产物可以自由进出膜内外，而包裹在膜内的生物大分子则不能泄露出来。 第三章综述了微囊化人工细胞的研究进展。 This dissertation consists of three parts. In the first part, the chemical constituents from the root of Valeriana wallichii were reported. In the second part, preparation and characteristics of L-Asparaginase Artificial cell were reported. The third part is a review on progress of microcapsule artificial cell. The first chapter is about the isolation and identification of the chemical constituents from the root of V. wallichii. Seventeen compounds were isolated from the ethanol extract of roots of V. wallichii through repeated column chromatography on normal and reversed phase silica gel. By the spectroscopic and chemical evidence, their structures were elucidated as valtrate (1), valechlorine (2), homobadrinal (3), baldrinal (4), acevaltrate (5), valeriotetrate C (6), valeriotetrate B (7), 4'-hydroxy-acetophenone (8), 7-hydroxy valtrate (9), 8-methylvalepotriate (10), 1,5-dihydroxy-3,8-epoxyvalechlorine A (11), didrovaltrate (12), daucosterol (13), hesperidin (14), prinsepiol-4-O-β-D-glucopyranoside (15), longiflorone (16), and ethyl glucoside (17). Among them, 6, 7, 10, and 11 are new compounds. 15, 16 and 9 were isolated from this plant for the first time. The absolute configuration of compound 11, an unusual iridoid bearing a C-10 chlor-group and an oxo-bridge connecting C-3 and C-8 resulting in a rigid skeleton, was confirmed. The second chapter is about the semi-permeable microcapsule of carboxymethyl konjac glucomannan-chitosan for L-asparaginase immobilization. Carboxymethyl konjac glucomannan-chitosan (CKGM-CS) microcapsules, which have good biocompatibility, prepared under very mild conditions via polyelectrostatic complexation, were used for immobilize L-asparaginase-a kind of drug for acute lymphoblastic leukemia (ALL). The activity and stability under different temperature and pH of the enzyme loaded-microcapsules were studied. The results indicated the immobilized enzyme has better stability and activity contrasting to the native enzyme. The study illustrates that the L-asparaginase could be protected in CKGM-CS microcapsules, the substrate and product could pass through the system freely.

A new micro/nanoencapsulated porphyrin formulation for PDT treatment

The highly hydrophobic 5,10,15-triphenyl-20-(3-N-methylpyridinium-yl)porphyrin(3MMe)cationic species was synthesized, characterized and encapsulated in marine atelocollagen/xanthane gum microcapsules by the coacervation method. Further reduction in the capsule size, from several microns down to about 300-400 nm, was carried out successfully by ultrasonic processing in the presence of up to 1.6% Tween 20 surfactant, without affecting the distribution of 3MMe in the oily core. The resulting creamlike product exhibited enhanced photodynamic activity but negligible cytotoxicity towards HeLa cells. The polymeric micro/nanocapsule formulation was found to be about 4 times more phototoxic than the respective phosphatidylcholine lipidic emulsion, demonstrating high potentiality for photodynamic therapy applications. (C) 2009 Elsevier B.V. All rights reserved.

Physicochemical Stability of Poly(lactide-co-glycolide) Nanocapsules Containing the Local Anesthetic Bupivacaine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Poly(Lactide-co-Glycolide) Nanocapsules Containing Benzocaine: Influence of the Composition of the Oily Nucleus on Physico-Chemical Properties and Anesthetic Activity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Validation of an HPLC Method for quantitative Determination of Benzocaine in PHBV-Microparticles and PLA-Nanoparticles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Screening of Formulation Variables for the Preparation of Poly(epsilon-caprolactone) Nanocapsules Containing the Local Anesthetic Benzocaine

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Benzocaine-loaded polymeric nanocapsules: Study of the anesthetic activities

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nanotechnology-based drug delivery systems for treatment of hyperproliferative skin diseases - a review

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)