Oridonin ameliorates neuropathological changes and behavioural deficits in a mouse model of cerebral amyloidosis

Alzheimer's disease (AD) is the most common form of neurodegeneration and the major cause of dementia. This multifactorial disorder is clinically defined by progressive behavioural and cognitive deficits, and neuropathologically characterized by β‐amyloid aggregation, hyperphosphorylated tau and neuroinflammation. Oridonin, a diterpenoid isolated from Chinese herb Rabdosia rubescens, has multiple biological properties, especially anti‐inflammatory and neuroregulatory activities. Potential therapeutic effects of Oridonin were investigated in an animal model of cerebral amyloidosis for AD, transgenic APP/PS1 mice. Oridonin was suspended in carboxymethylcellulose or loaded with a nanostructured emulsion, and was orally administrated or injected. Before, during and following the experimental treatments, behavioural tests were performed with these transgenic mice and their naive littermates. Following relatively short‐term treatments of 10 days, brain tissue of mice were removed for immunohistochemical assays. The results indicate that both oral treatment and injection of Oridonin significantly attenuated β‐amyloid deposition, plaque‐associated APP expression and microglial activation in brain of transgenic mice. Furthermore, injection of Oridonin‐nanoemulsion ameliorated deficits in nesting, an important affiliative behaviour, and in social interaction. Additional in vitro studies indicated that Oridonin effectively attenuated inflammatory reaction of macrophage and microglial cell lines. Our results suggest that Oridonin might be considered a promising therapeutic option for human AD or other neurodegenerative diseases.     

2,4,6-Triphenylaniline nanoemulsion formulation,optimization, and its application in type 2 diabetes mellitus

The secondary metabolite 2,4,6-triphenylaniline (TPA) was isolated from an endophytic fungi Alternaria longipes strain VITN14G of mangrove plant Avicennia officinalis, that exhibited satisfactory in vitro antidiabetic activity for type 2 diabetes mellitus (T2DM). The TPA was encapsulated using nanoemulsion (NE) to overcome the problem of stability and permeability to increase its therapeutic applications. Response surface methodology (RSM) was used for the optimization of the variables given, such as hydrodynamic diameter, surface charge, and polydispersity index (PDI). TPA was encapsulated using an optimized ratio of olive oil and tween 80 (2:1) significantly affected the response variables including particle size (124.8 nm), ζ potential (−46.0 mV), and PDI (0.396), and the encapsulation efficiency was found to be 95.93%. The TPA-loaded NE after MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) analysis showed nontoxic effects on L929 normal cell lines (areolar and adipose subcutaneous connective tissue of Mus musculus) with a viable percentage of 92%. In vitro release study revealed the slow and sustained release of the TPA over 48 hrs from NE under the Fickian diffusion mechanism and followed the Higuchi model for release kinetics. Further, the percentage of α-glucosidase and α-amylase inhibition rate of TPA-loaded NE was found to be 78.5 and 43.42%, respectively. The present study, therefore, can aid in the development of a novel drug delivery system as a therapeutic approach to T2DM.     

Use of artificial neural networks for analysis of the factors affecting particle size in mebudipine nanoemulsion

In this study, a nanoemulsion containing mebudipine [composed of ethyl oleate (oil phase), Tween 80 (T80), Span 80 (S80) (surfactants), polyethylene glycol 400, ethanol (cosurfactants), and deionized water] was prepared with the aim of improving its bioavailability for an effective antihypertensive therapy. Particle size of the formulation was measured by dynamic light scattering. Then, artificial neural networks were used in identifying factors that influence the particle size of the nanoemulsion. Three variables, namely, amount of surfactant system (T80?+?S80), amount of polyethylene glycol, and amount of ethanol as cosurfactants, were considered as input values and the particle size was used as output. The developed model showed that all the three inputs had some degrees of effect on particles size: increasing the value of each input decreased the size. Furthermore, amount of surfactant was found to be the dominant factor in controlling the final particle size of nanoemulsion.

Communicated by Ramaswamy H. Sarma     

The fungicidal activity of novel nanoemulsion (X8W60PC) against clinically important yeast and filamentous fungi

Surfactant nanoemulsions are water in oil preparations that proved to have a broad spectrum biocidal activity against a variety of microorganisms including Gram-positive and Gram-negative bacteria, spores and enveloped viruses. These preparations are non-toxic to the skin, mucous membrane and gastrointestinal tissues at biocidal concentrations. In this study, 0.1% of the nanoemulsion designated X8W₆₀PC has shown fungicidal activity against yeast including Candida albicans and C. tropicalis in 15 minutes. C. tropicalis was more sensitive than C. albicans, which required a longer time or a higher concentration of the nanoemulsion to achieve killing. Neutral to slightly alkaline pH was more effective in killing the yeast cells than acidic pH. Using the minimum inhibitory concentration assay, 0.08% of the nanoemulsion was inhibitory to C. albicans, and parapsilosis and filamentous fungi including Microsporum gypseum,Trichophyton mentagrophytes,Trichophyton rubrum,Aspergillus fumigatus andFusarium oxysporum.None of the individual ingredients was as effective a fungicidal as the nanoemulsion at equivalent concentration. This shows that the nanoemulsion structure is an important factor in the anti-fungal activity. The X8W₆₀PC has great potential as a topical anti-fungal agent and further investigation into the mechanism of fungicidal action is warranted.This revised version was published online in October 2005 with corrections to the Cover Date.     

Nanoemulsions of sulfonamide carbonic anhydrase inhibitors strongly inhibit the growth of Trypanosoma cruzi

Sulfonamide carbonic anhydrase (CA, EC 4.2.1.1) inhibitors targeting the α-class enzyme from the protozoan pathogen Trypanosoma cruzi, responsible of Chagas disease, were recently reported. Although many such derivatives showed low nanomolar activity in vitro, they were inefficient anti-T. cruzi agents in vivo. Here, we show that by formulating such sulfonamides as nanoemulsions in clove (Eugenia caryophyllus) oil, highly efficient anti-protozoan effects are observed against two different strains of T. cruzi. These effects are probably due to an enhanced permeation of the enzyme inhibitor through the nanoemulsion formulation, interfering in this way with the life cycle of the pathogen either by inhibiting pH regulation or carboxylating reactions in which bicarbonate/CO₂ are involved. This type of formulation of sulfonamides with T. cruzi CA inhibitory effects may lead to novel therapeutic approaches against this orphan disease.     

矾冰纳米乳对临床常见病原菌体外抗菌活性的研究

研究纳米化提高白矾与冰片复合物体外抗菌活性的效果。分别采用琼脂扩散法、体外杀菌试验及试管稀释法,测定白矾与冰片O/W型复合纳米乳对临床常见病原菌的体外抑菌、杀菌效果及最低抑菌浓度(MIC),实验中以等浓度矾冰液作为对照。结果显示,矾冰纳米乳对金黄色葡萄球菌、表皮葡萄球菌、大肠埃希菌、铜绿假单胞菌、白假丝酵母菌的抑制及杀灭活性均明显强于矾冰液(P0.05)。矾冰纳米乳对金黄色葡萄球菌、铜绿假单胞菌、大肠埃希菌临床菌株MIC90值分别为1.02、2.04和2.04 mg/mL,均明显低于矾冰液的MIC90值(P0.05)。上述实验结果提示,矾冰纳米乳与矾冰液均有广谱体外抑菌及杀菌活性,白矾及冰片复合物纳米化可提高抗菌效果。     

Solid lipid nanoparticles and nanoemulsions containing ceramides: Preparation and physicochemical characterization

Nanoemulsions (NEs) and solid lipid nanoparticles (SLNs) are widely used colloidal carriers for bioactive compounds. They are used in therapeutic, diagnostic, and cosmetic formulations. Ceramides are main components of the stratum corneum and are essential for the efficient barrier function. Their very high lipophilicity renders them difficult to incorporate in an acceptable formulation. The aim of this work was to investigate the possibility of using the benefits of nanotechnology in the efficient topical delivery of ceramides formulated as NEs or SLNs. The physicochemical characteristics of such carriers incorporating ceramides were investigated and their stability over time was assessed. Their morphology was examined under a scanning electron microscope and the interactions of their components were studied by differential scanning calorimetry. The results showed that the nanoemulsions can incorporate a high percentage (48.4% of total lipids by weight) of ceramides giving more homogeneous particle distributions of spherical-shaped nanoparticles and they maintained their characteristics over time. On the contrary, SLNs’ incorporation of ceramide higher than 10.8% of total lipids by weight led to the formation of rod-like nanoparticles deteriorating the homogeneity of the particle distribution, as depicted on the high polydispersity indexes of the corresponding formulations. The results demonstrate that NEs may be the more suitable carrier, compared to SLNs.     

质粒纳米乳剂的制备与阴离子交换色谱测定方法

以纳米乳剂为载体包裹草原兔尾鼠卵透明带3DNA疫苗,制备获得了纳米乳剂DNA疫苗,并对其进行了质量评价。采用界面乳化法制备质粒纳米乳剂,用电子显微镜测定了其粒径及其分布,根据质粒的带电特性,利用强阴离子Q SepharoseTMXL色谱柱分离纳米乳剂和游离质粒,建立了强阴离子交换柱质粒纳米乳剂包封率的快速测定方法。结果表明:制备的纳米乳剂DNA疫苗的平均粒径为(23±10)nm,包封率为80.5%。选择0.05mol/L的Tris-HCl为平衡液,流速为0.7mL/min,紫外检测波长260nm,柱温30℃,进样量为2mL的实验条件,质粒的含量和峰面积的线性关系良好(r=0.9983),加样回收率在95%以上,该方法简便快速、灵敏度高,重复性好,可用于纳米乳剂DNA疫苗包封率的快速测定。     

Preparation and Evaluation of Self-nanoemulsifying Tablets of Carvedilol

The purpose of this study was to combine the advantages of self-nanoemulsifying drug delivery systems and tablets as a conventional dosage form emphasizing the excipients’ effect on the development of a new dosage form. Systems composed of HCO-40, Transcutol® HP, and medium-chain triglyceride were prepared. Essential properties of the prepared systems regarding carvedilol solubility, a model drug, and self-emulsification time were determined. In order to optimize self-nanoemulsifying drug delivery systems (SNEDDS), formulation dispersion–drug precipitation test was performed in the absence and presence of cellulosic polymers. Furthermore, SNEDDS was loaded onto liquisolid powders. P-glycoprotein (P-gp) activity of the selected SNEDDS was tested using HCT-116 cells. Carvedilol showed acceptable solubility in the selected excipients. It also demonstrated improvement in the stability upon dilution with aqueous media in the presence of cellulosic polymers. Use of granulated silicon dioxide improved the physical properties of liquisolid powders containing SNEDDS. It improved the compressibility of the selected powders and the tested SNEDDS showed marked P-gp inhibition activity. Prepared self-nanoemulsifying tablet produced acceptable properties of immediate-release dosage forms and expected to increase the bioavailability of carvedilol.     

经皮给药载体载MD-CPT透明质酸纳米乳的细胞吞噬与体内药代动力学研究

本文在研究制备了包载10,11-亚甲二氧基喜树碱(MD-CPT)的透明质酸纳米乳(HANs)经皮给药系统的基础上,进一步研究了载MD-CPT透明质酸纳米乳的细胞吞噬,并进行了体内药代动力学分析.通过优化制备条件,得到了皮肤渗透性良好的缓释剂型.从CLSM观察到药物被细胞摄入并传递入细胞核,同时,载药纳米乳的细胞吞噬效率呈时间依赖性,不同细胞株HSF、HUVES、MCF-7、KF的细胞吞噬率略有不同.用Rhodanmine B标记HANs,通过荧光显微镜观察到载药纳米乳透过角质层到达真皮层的拟动态过程.利用HPLC检测MD-CPT血药浓度,测得经皮给药半衰期T1/2是静脉注射的3.6倍,肌肉注射的1.6倍,体内药物滞留时间显著增加;血药浓度峰谷值差异小,曲线平缓,说明经皮给药能保证血药浓度呈现可控的持续性.最终通过活体成像系统和组织切片荧光显微镜,直观地反映出经皮给药后药物在大鼠体内的分布情况和各组织器官药物含量,确定载药纳米乳主要采取胞间渗透的扩散方式,在局部给药的区域滞留时间较长,有利于对浅表性的病灶区持续给药,延长药效,而剩余的MD-CPT和解离的HANs都进入了血液循环,最终通过新陈代谢被排出体外.为无创型HANs经皮给药系统应用于浅表性肿瘤治疗提供了理论基础.