Genotoxicity evaluation of titanium dioxide nanoparticles using the Ames test and Comet assay

Titanium dioxide nanoparticles (TiO₂‐NPs) are being used increasingly for various industrial and consumer products, including cosmetics and sunscreens because of their photoactive properties. Therefore, the toxicity of TiO₂‐NPs needs to be thoroughly understood. In the present study, the genotoxicity of 10nm uncoated sphere TiO₂‐NPs with an anatase crystalline structure, which has been well characterized in a previous study, was assessed using the Salmonella reverse mutation assay (Ames test) and the single‐cell gel electrophoresis (Comet) assay. For the Ames test, Salmonella strains TA102, TA100, TA1537, TA98 and TA1535 were preincubated with eight different concentrations of the TiO₂‐NPs for 4 h at 37 °C, ranging from 0 to 4915.2 µg per plate. No mutation induction was found. Analyses with transmission electron microscopy (TEM) and energy‐dispersive X‐ray spectroscopy (EDS) showed that the TiO₂‐NPs were not able to enter the bacterial cell. For the Comet assay, TK6 cells were treated with 0–200 µg ml^–1 TiO₂‐NPs for 24 h at 37 °C to detect DNA damage. Although the TK6 cells did take up TiO₂‐NPs, no significant induction of DNA breakage or oxidative DNA damage was observed in the treated cells using the standard alkaline Comet assay and the endonuclease III (EndoIII) and human 8‐hydroxyguanine DNA‐glycosylase (hOGG1)‐modified Comet assay, respectively. These results suggest that TiO₂‐NPs are not genotoxic under the conditions of the Ames test and Comet assay. Published 2012. This article is a US Government work and is in the public domain in the USA.     

Antioxidant activity of idebenone-loaded neutral and cationic solid–lipid nanoparticles

Abstract

Idebenone (IDE) is a lipophilic benzoquinone electron carrier synthetic analogue of coenzyme Q10, which behaves as an antioxidant and free radical scavenging molecule. Recently, the therapeutic application of IDE in Leber’s hereditary optic neuropathy has been discussed. This work was aimed at evaluating the encapsulation of IDE in solid–lipid nanoparticles (SLN). In particular, we tested the possibility of adapting the quasi-emulsion solvent diffusion technique, already proposed to produce polymeric nanoparticles, to prepare positively charged SLN with different compositions. Such a charge, due to the addition of a cationic lipid, would facilitate the interaction with the negatively charged eye surface epithelium, with a consequent longer pre-corneal residence time of the colloidal systems. In a preliminary evaluation of the produced IDE-loaded SLN, the antioxidant activity of the drug was demonstrated using an oxygen radical absorbance capacity assay. Encapsulation of the drug in the nanocarrier systems seems able to protect IDE from degradation and prolong its antioxidant potential.     

Comparative genotoxicity of nanosilver in human liver HepG2 and colon Caco2 cells evaluated by fluorescent microscopy of cytochalasin B‐blocked micronucleus formation

As a consequence of the increased use of silver nanoparticles in food, food contact materials, dietary supplements and cosmetics to prevent fungal and bacterial growth, there is a need for validated rapid screening methods to assess the safety of nanoparticle exposure. This study evaluated two widely used in vitro cell culture models, human liver HepG2 cells and human colon Caco2 cells, as tools for assessing the potential genotoxicity of 20‐nm nanosilver. The average silver nanoparticle size as determined by transmission electron microscopy (TEM) was 20.4 nm. Dynamic light scattering (DLS) analysis showed no large agglomeration of the silver nanoparticles. The silver concentration in a 20‐nm nanosilver solution determined by the inductively coupled plasma–mass spectrometry (ICP‐MS) analysis was 0.962 mg ml^?1. Analysis by ICP‐MS and TEM demonstrated the uptake of 20‐nm silver by both HepG2 and Caco2 cells. Genotoxicity was determined by the cytochalasin B‐blocked micronucleus assay with acridine orange staining and fluorescence microscopy. Concentration‐ and time‐dependent increases in the frequency of binucleated cells with micronuclei induced by the nanosilver was observed in the concentration range of 0.5 to 15 µg ml^?1 in both HepG2 and Caco2 cells compared with the control. Our results indicated that HepG2 cells were more sensitive than Caco2 cells in terms of micronuclei formation induced by nanosilver exposure. In summary, the results of this study indicate that the widely used in vitro models, HepG2 and Caco2 cells in culture, represent potential screening models for prediction of genotoxicity of silver nanoparticles by in vitro micronucleus assay. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.     

吡喹酮固体脂质纳米粒的研制

目的采用超声分散法制备吡喹酮固体脂质纳米粒,并考察制备过程中的主要影响因素。方法首先通过试验确定制备工艺参数,然后考察各处方因素对粒径大小和稳定性的影响,最后以包封率为评价指标,采用正交实验设计法确定最优处方。结果透射电镜测得纳米粒为类圆球状,粒径分布较均匀。动态光散射法测得样品的粒径为(100±21)nm,包封率为(79.3±0.69)%,平均zeta电位值为-66.3 mV。结论以山嵛酸甘油酯和乙酸丁酯为脂质材料,豆磷脂、泊洛沙姆188和硬脂酸钠为复配乳化剂,采用超声分散法可以简便、快速制得吡喹酮固体脂质纳米粒。     

蟾酥固体脂质纳米粒冻干工艺及其表征

目的 研究了蟾酥固体脂质纳米粒冻干剂的工艺及表征。方法以外观、色泽、再分散性为指标，考察了不同工艺条件对蟾酥固体脂质纳米粒冻干剂重建的影响，对冻干工艺参数进行了优化，并对蟾酥固体脂质纳米粒冻干剂进行了研究。结果5％乳糖和5％葡萄糖显示了优良的保护作用和再分散性，优化的冻干工艺为：-45℃预冻10h，升温至-30℃维持6h，再升温至-10℃维持3h，再升温至0℃维持2h，最后升温至25℃维持3h。结论通过支架剂的筛选和优化冻干工艺参数可以获得稳定的固体脂质纳米粒冻干剂。     

酮洛芬固体脂质纳米粒的制备

目的：微乳法制备固体脂质纳米粒,以酮洛芬作为模型药物,考查其载药性能。方法：通过对空白微乳粒径和稳定性考查,确定优化处方,将其保温分散于冷水中制备固体脂质纳米粒。对影响其质量的工艺因素和处方因素进行考查和优化设计,筛选最优处方。结果：制备固体脂质纳米粒的直接影响因素包括脂质用量、药物的用量、冷水相温度和微乳保温温度等,所得固体脂质纳米粒的平均粒径（143.9±1.2）nm,多分散系数为0.443。载药固体脂质纳米粒包封率为81.47%,载药量为8.16%。结论：该法稳定可靠,可用于酮洛芬固体脂质纳米粒的制备。     

RP-HPLC法测定多西他赛固体脂质纳米粒中多西他赛的含量

目的建立RP-HPLC法测定多西他赛固体脂质纳米粒中多西他赛的含量。方法色谱柱:Century SIL BDS C18(4.6 mm×200 mm,5μm),检测波长:228 nm,流动相:乙腈-水(体积比为60∶40),流速:1.0 mL.min-1,柱温:室温。结果多西他赛与其他组分分离良好,线性1.05~21.0 mg.L-1(r=0.999 9),日内、日间精密度为1.12%、1.03%,平均回收率为99.3%,RSD=0.95%。结论可作为该制剂的质量控制方法。     

Comparative genotoxicity of nanosilver in human liver HepG2 and colon Caco2 cells evaluated by a flow cytometric in vitro micronucleus assay

Two widely used in vitro cell culture models, human liver HepG2 cells and human colon Caco2 cells, and flow cytometry techniques were evaluated as tools for rapid screening of potential genotoxicity of food‐related nanosilver. Comparative genotoxic potential of 20 nm silver was evaluated in HepG2 and Caco2 cell cultures by a flow cytometric‐based in vitro micronucleus assay. The nanosilver, characterized by the dynamic light scattering, transmission electron microscopy and inductively coupled plasma–mass spectrometry analysis, showed no agglomeration of the silver nanoparticles. The inductively coupled plasma–mass spectrometry and transmission electron microscopy analysis demonstrated the uptake of 20 nm silver by both cell types. The 20 nm silver exposure of HepG2 cells increased the concentration‐dependent micronucleus formation sevenfold at 10 µg ml^–1 concentration in attached cell conditions and 1.3‐fold in cell suspension conditions compared to the vehicle controls. However, compared to the vehicle controls, the 20 nm silver exposure of Caco2 cells increased the micronucleus formation 1.2‐fold at a concentration of 10 µg ml^–1 both in the attached cell conditions as well as in the cell suspension conditions. Our results of flow cytometric in vitro micronucleus assay appear to suggest that the HepG2 cells are more susceptible to the nanosilver‐induced micronucleus formation than the Caco2 cells compared to the vehicle controls. However, our results also suggest that the widely used in vitro models, HepG2 and Caco2 cells and the flow cytometric in vitro micronucleus assay are valuable tools for the rapid screening of genotoxic potential of nanosilver and deserve more careful evaluation. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.     

微乳化技术制备固体脂质纳米粒微乳化技术制备固体脂质纳米粒

目的采用微乳化技术制备固体脂质纳米粒（SLN）。方法以硬脂酸为油相，卵磷脂为乳化剂，乙醇为助乳化剂，蒸馏水为水相，按不同比例混合制备微乳。通过改变卵磷脂与乙醇的配比（K_m），绘制出不同K_m值下的三元相图。从中选择适宜的微乳，将其分散于冷水中制备SLN。考察了工艺因素和处方因素对SLN制备和SLN质量的影响。在单因素考察的基础上，采用正交设计优化工艺，并对优化所得的工艺进行重现性考察。结果水相温度（T_w）、微乳的温度（T_i）、微乳注入速度（r_d）均直接影响SLN的制备，其中水相温度是影响SLN质量的重要因素；微乳各组分的配比、微乳与水相的比例也对SLN的质量有一定影响。结论微乳化技术制备固体脂质纳米粒是可行的。     

RP-HPLC法测定固体脂质纳米粒中β-榄香烯的含量

目的建立固体脂质纳米粒注射液中β榄香烯的反相高效液相色谱法。方法色谱柱:HypersilBDSC18(4.6mm×200mm,5μm);流动相:乙腈水(体积比为88∶12);检测波长:210nm;柱温:30℃。结果β榄香烯与其他组分分离良好,线性范围10.6～53.0mg·L-1(r=0.9999),平均回收率为99.6%,RSD为0.93%(n=5)。结论方法简便、准确,可作为该制剂的质量控制方法。     

Preparation and characterization of nocodazole-loaded solid lipid nanoparticles

Abstract

Nocodazole (NCD) has more carcinogenic effect than similar drugs. Moreover, it has low drug release time and high particle size. Solid Lipid Nanoparticles (SLNs) have been evaluated for decrease in particle size and therefore increase in drug release time, for such drugs. In this study, NCD has been successfully incorporated into SLNs systems and remained stable for a period of 90 days. NCD structure related to the chemical nature of solid lipid is a key factor to decide whether anticarcinogenic agent will be incorporated in the long term and for a controlled optimization of active ingredient incorporation and loading, intensive characterization of the physical state of the lipid particles were highly essential. Thus, NMR, FT-IR, DSC (for thermal behavior) analyses were performed and the results did not indicate any problem on stability. Moreover, SLNs were decreased size of NCD in addition to increase in time of the drug release. After SLN preparation, particle size, polydispersity index, electrical conductivity and zeta potential were measured and drug release from NCD-loaded SLNs were performed. These values seem to be of the desired range.     

人参皂苷Rd固体脂质纳米粒的制备

目的:制备人参皂苷Rd固体脂质纳米粒,并考察其理化性质。方法:从旋转薄膜-超声分散法、乳化蒸发-低温固化法、高剪切乳化超声法和高压乳匀法中优选出制备方法;在脂质、表面活性剂等辅料和主药用量的单因素考察基础上,采用正交试验设计,确定最佳处方组成和制备工艺条件;用凝胶柱色谱和HPLC法测定包封率,透射电镜观察形态,激光粒径分析仪测定粒径和Zeta电位。结果:脂质、表面活性剂、助表面活性剂和主药的用量对Rd固体脂质纳米粒的粒径、Zeta电位和包封率均有不同程度的影响。高压乳匀法适合制备Rd固体脂质纳米粒。纳米粒表面呈圆整的球状,大小相近,分散均匀;平均粒径为(102.7±27.0)nm,Zeta电位为(-44.9±9.5)mV,包封率和载药量分别为(81.8±2.6)%和(6.37±0.21)%(n=3)。纳米粒稳定性良好,在4℃下保存4周后,粒径和包封率变化不明显。结论:高压乳匀法适合制备人参皂苷Rd固体脂质纳米粒,工艺稳定可行。     

Skin permeation of buprenorphine and its ester prodrugs from lipid nanoparticles: lipid emulsion,nanostructured lipid carriers and solid lipid nanoparticles

The aim of this study was to develop and characterize lipid nanoparticle systems for the transdermal delivery of buprenorphine and its prodrugs. A panel of three buprenorphine prodrugs with ester chains of various lengths was synthesized and characterized by solubility, capacity factor (log K′), partitioning between lipids and water and the ability to penetrate nude mouse skin. Colloidal systems made of squalene (lipid emulsion, LE), squalene + Precirol (nanostructured lipid carriers, NLC) and Precirol (solid lipid nanoparticles, SLN) as the lipid core material were prepared. Differential scanning calorimetry showed that the SLN had a more-ordered crystalline lattice in the inner matrix compared to the NLC. The particle size ranged from 220–300 nm, with NLC showing the smallest size. All prodrugs were highly lipophilic and chemically stable, but enzymatically unstable in skin homogenate and plasma. The in vitro permeation results exhibited a lower skin delivery of drug/prodrug with an increase in the alkyl chain length. SLN produced the highest drug/prodrug permeation, followed by the NLC and LE. A small inter-subject variation was also observed with SLN carriers. SLN with soybean phosphatidylcholine (SLN-PC) as the lipophilic emulsifier showed a higher drug/prodrug delivery across the skin compared to SLN with Myverol, a palmitinic acid monoglyceride. The in vitro permeation of the prodrugs occurred in a sustained manner for SLN-PC. The skin permeation of buprenorphine could be adjusted within a wide range by combining a prodrug strategy and lipid nanoparticles.     

左旋多巴固体脂质纳米粒的制备及包封率测定

目的:用微乳法制备左旋多巴固体脂质纳米粒(LDP-SLN),并建立包封率的测定方法。方法:通过绘制三元相图,采用微乳法制备LDP-SLN,用TEM和激光粒度仪进行了颗粒形貌和粒径分布的研究,用葡聚糖凝胶层析法分离测定包封率。对其粒径、形态、包封率等理化性质进行研究,并考察其稳定性。结果:实验制得LDP-SLN为稳定的略泛蓝色乳光的纳米混悬液,在透射电镜下显示为较为均匀的球体,激光粒度测定平均粒径为108nm,多分散系数1.153;4℃放置2个月,粒径、包封率无显著变化。包封率测定的线性范围为2～100mg·mL-1,线性良好(r=0.9999),精密度符合要求,LDP-SLN上柱洗脱后分离度和回收率均符合要求。结论:该研究中制备了物理性质较为稳定的LDP-SLN,建立了合适的包封率测定方法,并考查初步稳定性较好。     

Galactosylated solid lipid nanoparticles with cucurbitacin B improves the liver targetability

This study intended to prepare liver-targeting solid lipid nanoparticles (SLNs) with a hepatoprotective drug, cucurbitacin B (Cuc B), using a galactosylated lipid, N-hexadecyl lactobionamide (N-HLBA). The galactosyl-lipid N-HLBA was prepared via the lactone form intermediates of lactobionic acid and synthesized by anchoring galactose to hexadecylamine lipid. The Cuc B-loaded galactosylated and conventional SLNs were successfully prepared by a high-pressure homogenization method. The two SLNs showed similar physical and pharmaceutical properties, including: the particle size measured by laser diffraction was 135?nm for galactosylated SLN (GalSLN) and 123?nm for conventional SLNs (CSLN); zeta potentials were ?31.6 mV (GalSLN) and ?34.3 mV(CSLN); in vitro release behavior of the two SLNs was similar, and both showed the biphasic drug release pattern with burst release at the initial stage and prolonged release afterwards. In contrast, the two SLNs demonstrated a marked difference in in vitro cellular cytotoxicity and in vivo tissue distribution performances. The IC₅₀ values of Cuc B in the two SLNs were by far lower than those of Cuc B solution and further Cuc B-GalSLN had about half the IC₅₀ value of Cuc B-CSLN. These results indicated that the encapsulation of Cuc B in SLNs resulted in the enhancement of cytotoxic activity, and galactosyl ligand could further enhance the cellular accumulation and cytotoxicity of Cuc B. The weighted-average overall drug targeting efficiency (Te) was used to evaluate the liver targetability. Cuc B-GalSLN gave a relatively high (Te)_liver value of 63.6%, ～ 2.5-times greater than that of Cuc B-CSLN (25.3%) and Cuc B solution (23.8%). In summary, the incorporation of N-HLBA into SLNs significantly enhanced the liver targetability of Cuc B-loaded SLNs and GalSLN had a great potential as a drug delivery carrier for improved liver targetability.     

Development and characterization of 5-FU bearing ferritin appended solid lipid nanoparticles for tumour targeting

Ferritin coupled solid lipid nanoparticles were investigated for tumour targeting. Solid lipid nanoparticles were prepared using HSPC, cholesterol, DSPE and triolien. The SLNs without ferritin which has similar lipid composition were used for comparison. SLNs preparations were characterized for shape, size and percentage entrapment. The average size of SLNs was found to be in the range 110–152 nm and maximum drug entrapment was found to be 34.6–39.1%. In vitro drug release from the formulations is obeying fickian release kinetics. Cellular uptake and IC₅₀ values of the formulation were determined in vitro in MDA-MB-468 breast cancer cells. In vitro cell binding of Fr-SLN exhibits 7.7-folds higher binding to MDA-MB-468 breast cancer cells in comparison to plain SLNs. Ex-vivo cytotoxicity assay on targeted nanoparticles gave IC₅₀ of 1.28 µM and non-targeted nanoparticles gave IC₅₀ of 3.56 µM. In therapeutic experiments, 5-FU, SLNs and Fr-SLNs were administered at the dose of 10 mg 5-FU/kg body weight to MDA-MB-468 tumour bearing Balb/c mice. Administration of Fr-SLNs formulation results in effective reduction in tumour growth as compared with free 5-FU and plain SLNs. The result demonstrates that this delivery system possessed an enhanced anti-tumour activity. The results warrant further evaluation of this delivery system.     

溶剂扩散法制备丙酸倍氯米松固体脂质纳米粒溶剂扩散法制备丙酸倍氯米松固体脂质纳米粒

目的 建立一种高效的固体脂质纳米粒制备与分离方法。方法 用水性溶剂扩散法,制备得到甘油单硬脂酸酯固体脂质纳米粒。通过调节纳米粒表面Zeta电位,提高纳米粒的回收率。结果 用水性溶剂扩散法可以简便、快速制备得到含药固体脂质纳米粒,低转速离心(4 000 r·min^-1)即可达到纳米粒与分散体系之间的分离,回收率明显高于未调节纳米粒表面Zeta电位条件下的高速离心分离方法。用本法制备得到的纳米粒在最初3 h有药物的突释现象,随后4 d药物的释放明显缓慢,每天释放约药物总量的6%。结论 水性溶剂扩散法适用于固体脂质纳米粒的制备,得到的固体脂质纳米粒可实现药物的控制释放。     

溶剂扩散法制备丙酸倍氯米松固体脂质纳米粒

目的　建立一种高效的固体脂质纳米粒制备与分离方法。方法　用水性溶剂扩散法 ,制备得到甘油单硬脂酸酯固体脂质纳米粒。通过调节纳米粒表面Zeta电位 ,提高纳米粒的回收率。结果　用水性溶剂扩散法可以简便、快速制备得到含药固体脂质纳米粒 ,低转速离心 (40 0 0r·min- 1 )即可达到纳米粒与分散体系之间的分离 ,回收率明显高于未调节纳米粒表面Zeta电位条件下的高速离心分离方法。用本法制备得到的纳米粒在最初 3h有药物的突释现象 ,随后 4d药物的释放明显缓慢 ,每天释放约药物总量的 6%。结论　水性溶剂扩散法适用于固体脂质纳米粒的制备 ,得到的固体脂质纳米粒可实现药物的控制释放     

非洛地平-硬脂酸固体脂质纳米粒的制备及其体外透皮吸收研究

目的:以固体脂质纳米粒为栽体,通过透皮给药达到提高非洛地平透皮吸收及缓释长效的目的.方法:采用溶剂挥发-超声法制备非洛地平固体脂质纳米粒水分散体,以大鼠皮肤为渗透屏障对非洛地平固体脂质纳米粒的经皮渗透进行研究.结果:非洛地平-硬脂酸固体脂质纳米粒为类球形实体粒子,平均粒径范围在50～150 nm,包封率大于85%,栽药量大于7%,药物体外释放符合一级动力学过程.体外经皮渗透速率显著高于空白对照组.结论:非洛地平固体脂质纳米粒处方设计合理,制备工艺可靠,以纳米粒作为透皮给药载体具有广阔的发展前景.