Effect of different forms of anionic nanoclays on cytotoxicity

Anionic nanoclays, so-called layered double hydroxide (LDH) nanoparticles, have been extensively applied as drug delivery systems, since they efficiently enter cells via endocytosis pathway and possess controlled release property. However, the stability of LDHs varies, depending on the type of interlayer anions, which can also affect their toxicity. In this study, we investigated the effects of two different forms of LDH, carbonate form (MgAl-LDH-CO3) and chloride form (MgAl-LDH-Cl), on cytotoxicity in human lung epithelial cells. The result showed that MgAl-LDH-Cl was more easily dissolved into metal ions under simulated lysosomal (pH 4.5) and body fluid (pH 7.4) conditions than did MgAl-LDH-CO3. According to cytotoxicity evaluation, MgAl-LDH-CO3 exhibited high toxicity compared with MgAl-LDH-Cl in terms of induction of oxidative stress, apoptosis and membrane damage. These results suggest that easily dissoluble MgAl-LDH-Cl has low cytotoxicity, while high stability of MgAl-LDH-CO3 is correlated to elevated cytotoxicity.     

Intracellular drug delivery of layered double hydroxide nanoparticles

Intracellular drug delivery of layered double hydroxide (LDH) nanocarriers have been examined in human osteosarcoma Saos-2 cell culture line by both electron and confocal microscopies. For transmission electron microsopic (TEM) study, LDHs and anticancer drug, methotrexate (MTX) loaded LDHs were synthesized and the particle size was controlled. From the scanning electron microscopic (SEM) studies, morphologies of LDH nanoparticle and its MTX intercalated form were proven to be platelike hexagonal with an average size of approximately 150 nm. In order to understand the cellular penetration behavior, both nanoparticles were treated to human osteosarcoma Saos-2 cell culture lines and the cellular uptake pattern with respect to incubation time was observed by TEM and SEM. We observed that the nanoparticles are attached at the cellular membrane at first and then internalized into the cells via endocytosis within 1 h. Then are located in the intracellular vacuole (endosome). In order to examine the intracellular drug delivery mechanism of LDH nanoparticles, fluorescein 5-isothiocyanate (FITC) labeled MTX was intercalated into LDH and treated on Saos-2 cells. Laser scanning confocal microscopic studies revealed that the FITC-MTX molecules were first internalized with LDH nanocarriers via endocytosis, and located in endosome to deliver loaded drug to target cellular organ. It was, therefore, concluded that LDH could play a role as drug delivery nanocarriers.     

Methotrexate-conjugated L-lysine coated iron oxide magnetic nanoparticles for inhibition of MCF-7 breast cancer cells

Methotrexate (MTX), a stoichiometric inhibitor of dihydrofolate reductase enzyme, is a chemotherapeutic agent for treating a diversity of neoplasms. In this study, we design and developed a new formulation of MTX that serves as drug carrier and examined its cytotoxic effect in vitro. This target drug delivery system is dependent on the release of the MTX within the lysosomal compartment. The iron oxide magnetic nanoparticles (IONPs) were first surface-coated with L-lysine and subsequently conjugated with MTX through amidation between the carboxylic acid end groups on MTX and the amine groups on the IONPs surface. MTX-conjugated L-lysine coated IONPs (F-Lys-MTX NPs) was characterized by X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, vibrating sample magnetometer, and transmission electron microscopy techniques. The cytotoxicity of the void of MTX and F-Lys-MTX NPs were compared to each other by MTT assay of the treated MCF-7 cell lines. The results showed that the ζ-potential of F-Lys-MTX NPs was about ?5.49?mV and the average size was 43.72?±?4.73?nm. Model studies exhibited the release of MTX via peptide bond cleavage in the presence of proteinase K and at low pH. These studies specify that F-Lys-MTX NPs have a very remarkable anticancer effect, for breast cancer cell lines.     

Mg–Al layered double hydroxide–methotrexate nanohybrid drug delivery system: Evaluation of efficacy

Mg–Al layered double hydroxide nanoparticles were synthesized by one-pot co-precipitation method and anticancerous drug methotrexate was incorporated into it by in-situ ion exchange. The LDH–MTX nanohybrid produced moderately stable suspension in water, as predicted by zeta potential measurement. X-ray diffraction revealed that the basal spacing increased to nearly twice the same for pristine LDH on MTX intercalation. Thermogravimetric analyses confirmed an increase in thermal stability of the intercalated drug in the LDH framework. A striking enhancement in efficacy/sensitivity of MTX on the HCT-116 cells was obtained when intercalated within the LDH layers, as revealed by the attainment of half maximal inhibitory concentration of LDH–MTX nanohybrid by 48 h, whereas, bare MTX required 72 h for the same. The MTX release from MgAl-LDH–MTX hybrids in phosphate buffer saline at pH 7.4 followed a relatively slow, first order kinetics and was complete within 8 days following diffusion and crystal dissolution mechanism.     

An in vitro release study of 5-fluoro-uracil (5-FU) from swellable poly-(2-hydroxyethyl methacrylate) (PHEMA) nanoparticles

Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. The use of nanoparticles as drug delivery vehicles for anticancer therapeutics has great potential to revolutionize the future of cancer therapy. The present paper concerns both the optimizations of anticancer drug loading and its release from polymeric nanoparticles. The major aim of this study was to design poly (HEMA) nanoparticles as swelling controlled drug release system for anticancer drug. The prepared nanoparticles were characterized by Infra-Red (IR) Spectra, Particle size Analysis, and Scanning Electron Microscopy (SEM). The nanoparticles were loaded with widely used anticancer drug, 5-Fluorouracil, and controlled release of drug was investigated to observe the effects of various parameters such as percent loading of the drug, chemical architecture of the nanocarriers, pH, temperature, and nature of release media on the release profiles. The chemical stability of 5-Fluorouracil (5-FU) was also tested in phosphate buffer saline (PBS) (pH = 7.4) and release was studied in various simulated biological fluids. The prepared nanoparticles could provide a possible pathway for controlled and targeted delivery of anticancer drug, thus causing lower side effects and higher efficacy.     

Preparation and characterization of magnetic alginate-chitosan hydrogel beads loaded matrine

The aim of this study was to use alginate-chitosan (Alg-CS) hydrogel beads for developing an oral water-soluble drug delivery system, occupying pH-sensitive property and superparamagnetic. Matrine as a model drug was loaded in Alg-CS hydrogel beads to study the release character of the delivery system. The amount of matrine released from the beads was relatively low in pH 2.5 over 8?h (34.90%), but nearly all of the initial drug content was released in simulated intestinal fluid (SIF, pH 6.8) within 8?h. The results demonstrated that Alg-CS hydrogel beads possess unique pH-dependent swelling behaviors. In addition, the magnetic beads were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffractometry and vibrating-sample magnetometry. Magnetometer measurements data suggested that Alg-CS beads also had superparamagnetic property as well as fast magnetic response. It can be expected that the beads can deliver and release encapsulated anticancer agent at the tumor by the weak magnetic field, and hence could be potential candidates as an orally administered drug delivery system.     

Water‐Dispersible Fullerene Aggregates as a Targeted Anticancer Prodrug with both Chemo‐ and Photodynamic Therapeutic Actions

Prodrug therapy is one strategy to deliver anticancer drugs in a less reactive manner to reduce nonspecific cytotoxicity. A new multifunctional anticancer prodrug system based on water‐dispersible fullerene (C60) aggregates is introduced; this prodrug system demonstrates active targeting, pH‐responsive chemotherapy, and photodynamic therapeutic (PDT) properties. Incorporating (via a cleavable bond) an anticancer drug, which is doxorubicin (DOX) in this study, and a targeting ligand (folic acid) onto fullerene while maintaining an overall size of approximately 135 nm produces a more specific anticancer prodrug. This prodrug can enter folate receptor (FR)‐positive cancer cells and kill the cells via intracellular release of the active drug form. Moreover, the fullerene aggregate carrier exhibits PDT action; the cytotoxicity of the system towards FR‐positive cancer cells is increased in response to light irradiation. As the DOX drug molecules are conjugated onto fullerene, the DOX fluorescence is significantly quenched by the strong electron‐accepting capability of fullerene. The fluorescence restores upon release from fullerene, so this fluorescence quenching–restoring feature can be used to track intracellular DOX release. The combined effect of chemotherapy and PDT increases the therapeutic efficacy of the DOX–fullerene aggregate prodrug. This study provides useful insights into designing and improving the applicability of fullerene for other targeted cancer prodrug systems.     

Preparation and characterization of magnetic alginate-chitosan hydrogel beads loaded matrine

The aim of this study was to use alginate-chitosan (Alg-CS) hydrogel beads for developing an oral water-soluble drug delivery system, occupying pH-sensitive property and superparamagnetic. Matrine as a model drug was loaded in Alg-CS hydrogel beads to study the release character of the delivery system. The amount of matrine released from the beads was relatively low in pH 2.5 over 8?h (34.90%), but nearly all of the initial drug content was released in simulated intestinal fluid (SIF, pH 6.8) within 8?h. The results demonstrated that Alg-CS hydrogel beads possess unique pH-dependent swelling behaviors. In addition, the magnetic beads were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffractometry and vibrating-sample magnetometry. Magnetometer measurements data suggested that Alg-CS beads also had superparamagnetic property as well as fast magnetic response. It can be expected that the beads can deliver and release encapsulated anticancer agent at the tumor by the weak magnetic field, and hence could be potential candidates as an orally administered drug delivery system.     

Nanodiamond as the pH‐Responsive Vehicle for an Anticancer Drug

Cis‐dichlorodiammineplatinum(II) (CDDP, cisplatin), a widely used anticancer drug, is successfully loaded onto nanodiamond (ND) by adsorption and complexation. The CDDP–ND composite is characterized by IR spectroscopy, atomic absorption spectroscopy, thermogravimetric analysis, energy‐dispersive X‐ray spectroscopy, and X‐ray photoelectron spectroscopy. CDDP is released from the composite in phosphate‐buffered saline (PBS) of pH 6.0 at a rate higher than in PBS of pH 7.4. Therefore, it is predicted that the ND vehicle would deliver low concentrations of CDDP in the blood, but release much more drug after integration into the acidic cytoplasm, thereby reducing toxic side effects. The complexation between CDDP and the carboxyl groups on the ND surface is responsible for the pH‐responsive release property. The drug released from the composite retains the same cytotoxicity as free CDDP against human cervical cancer cells.     

Functionalisation of carbon nanotubes by methotrexate and study of synchronous photothermal effect of carbon nanotube and anticancer drug on cancer cell death

Carboxylated functionalised multi‐walled carbon nanotubes (f‐MWCNT) were synthesised. Furthermore, folic acid (FA) and methotrexate (MTX) through ethylenediamine (ED) were attached to the surface of f‐MWCNT to synthesise MWCNT–ED–FA and MWCNT–ED–MTX. Release studies of MTX as free drug and in MWCNT–ED–MTX were performed. These studies showed that MTX release rate from MWCNT–ED–MTX decreased in comparison with free MTX, which is due to the MTX attachment on the MWCNT. The anticancer effect of MWCNT–ED–FA and MWCNT–ED–MTX on the breast cancer cell line (MCF‐7) was studied. Studies have shown that MWCNT–ED–MTX cytotoxicity is more than that of MWCNT–ED–FA, which is due to the presence of MTX. Furthermore, the anticancer effects of MWCNT–ED–FA and MWCNT–ED–MTX in the presence of infrared laser radiation on the MCF7 cell were studied. The experiments showed that in the presence of the laser, the cytotoxicities of MWCNT–ED–FA and MWCNT–ED–MTX were the same and increased in comparison with laser absence, which indicates that the photothermal effect is stronger than other factors and mask their effects. This effect can be related to laser radiation absorption by MWCNT and its conversion to heat which can induce cancer cell death. Targeting studies have shown that MWCNT–ED–FA is targeted to the cancer cells due to the presence of FA.Inspec keywords: nanoparticles, nanomedicine, nanocomposites, drug delivery systems, tumours, carbon nanotubes, photothermal effects, toxicology, drugs, cancer, cellular biophysics, nanofabricationOther keywords: MWCNT–ED–FA, MWCNT–ED–MTX cytotoxicity, f‐MWCNT, synchronous photothermal effect, carbon nanotube, anticancer drug, cancer cell death     

Development of biocompatible fluorescent gelatin nanocarriers for cell imaging and anticancer drug targeting

In recent years, fluorescent carbon dots (CDs) have attracted a great deal of attention in imaging and related biomedical applications due to their excellent photoluminescence properties, low cost, high quantum yield and low cytotoxicity in comparison with semiconductor quantum dots based on metallic elements. In this paper, a new and simple design for development of CDs/gelatin nanoparticles (CDs/GNPs) is described which used as a novel methotrexate (MTX) nanocarrier and MCF-7 cell imaging. The obtained fluorescent nanocarriers were characterized using FTIR, SEM, XRD, DLS, PL, TGA, and zeta-potential analysis. Afterward, the performance of developed NPs was investigated through different in vitro tests such as MTT assay, fluorescence microscopy, and flow cytometry analyses. MTX was successfully loaded into the fluorescent NPs at physiological pH (7.4) by ionic interactions between anionic carboxylate groups of MTX and cationic amino groups on the surface of NPs. MTX releasing ability of the obtained nanocarrier was illustrated through the comparison of in vitro drug release at both simulated tumor tissue and physiological environment. The MTT assay revealed that the MTX-loaded nanocarriers have higher cytotoxicity in MCF-7 breast cancer cells than nanocarriers without MTX. Upon the obtained results, our fluorescent nanocarriers hold great potential as drug delivery carriers for the targeted MTX delivery to the cancer cells and biological fluorescent labeling.     

Dendron-polymer hybrid mediated anticancer drug delivery for suppression of mammary cancer

Dendron-polymer-based nanoscale and stimuli-responsive drug delivery systems have shown great promise in tumor-targeting accumulation without significant toxicity.Here we report a dendronized polymer-doxorubicin(DOX)hybrid(DPDH)with an improved in vivo drug delivery efficiency for cancer therapy compared with a linear polymer-DOX conjugate(LPDC).The in vitro drug release profile of DOX indicates that DPDH displays pH-responsive drug release due to cleavage of hydrazone bonds since a greater amount of DOX is released at pH 5.2 at a faster rate than at pH 7.4.DPDH efficiently enters 4 T1 cells and releases DOX to induce cytotoxicity and apoptosis.Owing to the dendronzied structure,DPDH has a significantly longer blood circulation time than LPDC.DPDH substantially enhances the therapeutic efficacy to suppress tumor growth in a 4 T1 mammary cancer model than LPDC as well as free drug,evidenced from tumor growth inhibition,TUNEL assessment and histological analysis.Biosafety of DPDH is also confirmed from hemolysis,body weight shifts during treatment and pathological analysis.This study demonstrates the use of dendronized polymer-DOX hybrids for specific drug molecules is a promising approach for drug delivery.     

水滑石作为药物载体--萘普生的插层和缓释

水滑石(LDHs)是由带正电荷类水镁石层和层间的可交换阴离子组成的阴离子型粘土化合物,由于它的生物适应性,能够以它为主体,以药物为客体,插层组装成超分子结构复合物.抗炎药萘普生采用共沉淀法一步插层进入LDHs,用X射线衍射、红外光谱及热分析方法表征了超分子结构,表明层间距离扩大了,即萘普生已经插层组装成功,并且以单层、垂直作用在层间.萘普生柱撑水滑石的药物释放度在模拟肠液(pH7.4的缓冲液)条件下测定,结果表明萘普生柱撑水滑石释放速度降低,具有缓释作用,说明药物--无机混合物材料能够用作有效的药物传输系统.     

pH-Controlled Delivery of Doxorubicin to Cancer Cells, Based on Small Mesoporous Carbon Nanospheres

Mesoporous carbon nanospheres (MCNs) with small diameters of ≈90 nm are developed as an efficient transmembrane delivery vehicle of an anticancer drug, doxorubicin (DOX). MCNs exhibit a high loading capacity toward DOX due to hydrophobic interactions and the supramolecular π stacking between DOX and the carbonaceous structures, on which the pH-dependent drug release are successfully achieved. Specifically, DOX can be loaded onto MCNs in basic solution and in a physiological pH range, while release occurs in acidic solution in its ionized state. By effective passive and active targeting, MCNs can be readily internalized into HeLa cells, where the carried DOX can be efficiently released in the acidic microenvironment of the tumors for further therapy. The endocytosis and cytotoxicity of DOX@MCNs toward HeLa cells are investigated by confocal microscopy and MTT assay. This smart pH-dependent drug loading and release property of DOX@MCNs makes it possible to reduce the cytotoxicity to normal tissues during circulation in the body since the normal physiological pH is ≈7.4.     

pH-Controlled drug release from mesoporous silica tablets coated with hydroxypropyl methylcellulose phthalate

A simple pH-controlled drug release system was successfully prepared by coating pH-sensitive polymer hydroxypropyl methylcellulose phthalate (HPMCP) on drug-loaded mesoporous SBA-15 tablet. Using famotidine (Famo) as a model drug, the effects of coating times and drying temperature on drug release were studied in detail to optimize the drug release system. In simulated gastric fluid (SGF, pH 1.2), it took only 2 h for Famo to be completely released from mesoporous silica tablet without HPMCP coating. Also in SGF, with the increase of coating times and drying temperature, the release of Famo was greatly delayed by HPMCP coating. For the tablet with twice coating of HPMCP and dried at 80 °C, only 4.0 wt.% of Famo could be released within 4 h. However, in simulated intestinal fluid (SIF, pH 7.4), HPMCP coating did not show obvious effect on the release of Famo.     

Preparation and in vitro release of dual-drug resinate complexes containing codeine and chlorpheniramine

Objective: To develop the dual-drug resinate complexes containing codeine and chlorpheniramine with a novel batch processing, characterize the dual-drug resinate complexes, and study its drug release behavior in vitro. Methods: A procedure of simultaneous dual-drug loading using combination solutions composed of different proportions of codeine phosphate and chlorpheniramine maleate was performed to achieve the specific resinate, and the dual-drug loading content was determined by high-performance liquid chromatography method. The dual-drug resinate complexes were characterized by a scanning electron microscope, and the formation mechanisms were confirmed with X-ray diffraction analyses and differential scanning calorimetric analyses. The release behavior of the two drugs from the dual-drug resinate complexes in vitro was studied in the media simulating in vivo environments (simulated gastric fluid: pH = 1.2 HCl, simulated in vivo ionic strength: 0.15 M NaCl, and simulated intestinal fluid: pH = 6.8 buffer solution containing KH2PO4–NaOH). Results: Scanning electron microscopic analyses proved that the dual-drug resinate complexes had the same appearance and characters as the initiative ion exchange resins (IERs). Via X-ray diffraction and differential scanning calorimetric analyses, it is found that the two drugs in dual-drug resinate complexes were combined with IERs by chemical bond. The drug-resinate complex, like IER, was in amorphous state. More than 90% of codeine phosphate was released in 15 minutes in three different media, whereas little amount of chlorpheniramine maleate was released in all the release time in the medium pH = 1.2 HCl, and the release equilibrium time was about 5 minutes, only 40% was released in the medium 0.15 M NaCl, and the equilibrium time was 40 minutes, and about 90% was released in the medium pH = 6.8 KH2PO4–NaOH. The increased ionic strength generally accelerated the release of the two drugs from the dual-drug resinate complexes. Conclusion: The dual-drug resinate complexes were formed through the reaction between the drugs and the IERs by chemical bond. The release behavior of the drug from the dual-drug resinate complexes in vitro was mainly correlated with the drug molecular structure, the eluting ionic strength, composition, and ionic strength of the release media. The novel dual-drug resinate complexes could be used to deliver two drugs in one therapeutic dose.     

Methotrexate loaded solid lipid nanoparticles (SLN) for effective treatment of carcinoma

Solid Lipid Nanoparticles (SLN) containing Methotrexate (MTX), an anticancer drug for intravenous administration was formulated and characterized. The SLN dispersions with MTX, stearic acid, and soya lecithin in the ratio of 1:4:1, 1:4:1.5, and 1:4:2, sodium taurodeoxycholate and distilled water were prepared by micro emulsification solidification method. The results show that the prepared MTX-SLN particles (with MTX-Stearic acid-Soya lecithin--1:4:2) have an average size of 270 nm with 51.3% drug entrapment. The in-vitro release was attained up to 15th h. The pharmacokinetic study reveals that the half-life and MRT of SLNs were higher than MTX solution. The life span of EAC (Ehrlich Ascite Carcinoma) bearing mice was increased when treated with MTX-SLNs (Methotrexate nanoparticles). These results clearly indicate that SLNs are a promising sustained release drug targeting system for lipophilic antitumour drugs.     

Formulation and Characterization of Magnetic Polyglutaraldehyde Nanoparticles as Carriers for Poly-l-Lysine-Methotrexate

Using the statistically optimised method, submicron magnetic polyglutaraldehyde nanoparticles (Fe-PGNP) with free surface carboxylic groups have been synthesized. A model anticancer agent methotrexate (MTX) has been chemically bonded onto the surface of these particles using poly-l-Lysine (PL) as a spacer. The drug release characteristics of the final delivery device, i.e. [Fe-PGNP]-PL-MTX, has been elucidated at 37˚C in a medium containing a proteolytic enzyme. Results demonstrate that using particles containing about 8% w/w of Fe₃O₄, and PL-MTX conjugate constituting 256 μg MTX per mg of PL, almost 50% of the conjugate can be covalently linked onto the carrier surface. Release studies failed to demonstrate the presence of free drug. However it appears that MTX-oligopeptides are released from the carrier as a result of the enzymatic hydrolysis of biodegradable bonds. It is suggested that [Fe-PGNP]-PL-MTX may be useful in the intracellular active targeting of bonded drug(s).     

Targeted anticancer prodrug with mesoporous silica nanoparticles as vehicles

A targeted anticancer prodrug system was fabricated with 180?nm mesoporous silica nanoparticles (MSNs) as carriers. The anticancer drug doxorubicin (DOX) was conjugated to the particles through an acid-sensitive carboxylic hydrazone linker which is cleavable under acidic conditions. Moreover, folic acid (FA) was covalently conjugated to the particle surface as the targeting ligand for folate receptors (FRs) overexpressed in some cancer cells. The in vitro release profiles of DOX from the MSN-based prodrug systems showed a strong dependence on the environmental pH values. The fluorescent dye FITC was incorporated in the MSNs so as to trace the cellular uptake on a fluorescence microscope. Cellular uptakes by HeLa, A549 and L929 cell lines were tested for FA-conjugated MSNs and plain MSNs respectively, and a much more efficient uptake by FR-positive cancer cells (HeLa) can be achieved by conjugation of folic acid onto the particles because of the folate-receptor-mediated endocytosis. The cytotoxicities for the FA-conjugated MSN prodrug, the plain MSN prodrug and free DOX against three cell lines were determined, and the result indicates that the FA-conjugated MSN prodrug exhibits higher cytotoxicity to FR-positive cells, and reduced cytotoxicity to FR-negative cells. Thus, with 180?nm MSNs as the carriers for the prodrug system, good drug loading, selective targeting and sustained release of drug molecules within targeted cancer cells can be realized. This study may provide useful insights for designing and improving the applicability of MSNs in targeted anticancer prodrug systems.     

PSY-g-PAA/APT/SA载药复合凝胶小球的制备及释药性能

采用离子凝胶法制备了欧车前胶-g-聚丙烯酸/凹凸棒黏土/海藻酸钠(PSY-g-PAA/APT/SA)载药复合凝胶小球,以双氯芬酸钠为模型药物,考察了pH敏感性和凹凸棒黏土含量对凝胶小球的包封率、载药率、溶胀性能和药物释放行为的影响。结果表明,当释放介质为模拟胃液(pH=1.2)时,药物基本不释放;而为模拟肠液(pH=6.8)时,5h后累积释放率超过90%,复合凝胶小球具有明显的pH敏感性。随着凝胶小球中凹凸棒黏土含量的增加,溶胀率和药物累积释放率均减小,表明凹凸棒黏土的引入可以减缓药物的突释效应。