Development of a Liposome Formulation for D-Cycloserine Local Delivery

Multilamellar liposomes loaded with D-cycloserine (D-CS) were prepared by a thin layer evaporation technique, followed by freezing and thawing cycles. Charged components and bioadhesive material, such as distearolylphosphatitylethanolamine covalently coupled with methoxypolyethyleneglycol, were used to prepare liposomes with different physico-chemical and technological properties. Negatively charged liposomes showed higher D-CS encapsulation efficiency (about 37%, w/w) than neutral and positively charged liposomes (about 5 and 17%, w/w, respectively). All formulations showed in vitro, after a burst effect, a prolonged release of the encapsulated drug.

Lipid vesicles made of dipalmitoylphosphatidylcholine (DPPC) were used as a biomembrane model to evaluate in vitro the interaction of D-CS with biological membranes. Differential scanning calorimetry was used as a simple and noninvasive technique of analysis. D-CS was distributed in the aqueous compartments of liposomes for interaction with the phospholipid polar head-groups (enhancement of Δ?H value). However, due to its high diffusibility the drug was also able to freely permeate through DPPC liposomes, altering during this passage the hydrophobic domains of the bilayers.

Stability studies were performed at different temperatures and pH values to assay the integrity of the drug during the liposome production steps. D-CS was rapidly degraded at acidic pH, but no significant hydrolysis was observed at pH 7.4 after 7 days.     

A Novel Nanoparticle Formulation for Sustained Paclitaxel Delivery

Purpose  To develop a novel nanoparticle drug delivery system consisting of chitosan and glyceryl monooleate (GMO) for the delivery of a wide variety of therapeutics including paclitaxel. Methods  Chitosan/GMO nanoparticles were prepared by multiple emulsion (o/w/o) solvent evaporation methods. Particle size and surface charge were determined. The morphological characteristics and cellular adhesion were evaluated with surface or transmission electron microscopy methods. The drug loading, encapsulation efficiency, in vitro release and cellular uptake were determined using HPLC methods. The safety and efficacy were evaluated by MTT cytotoxicity assay in human breast cancer cells (MDA-MB-231). Results  These studies provide conceptual proof that chitosan/GMO can form polycationic nano-sized particles (400 to 700 nm). The formulation demonstrates high yields (98 to 100%) and similar entrapment efficiencies. The lyophilized powder can be stored and easily be resuspended in an aqueous matrix. The nanoparticles have a hydrophobic inner-core with a hydrophilic coating that exhibits a significant positive charge and sustained release characteristics. This novel nanoparticle formulation shows evidence of mucoadhesive properties; a fourfold increased cellular uptake and a 1000-fold reduction in the IC₅₀ of PTX. Conclusion  These advantages allow lower doses of PTX to achieve a therapeutic effect, thus presumably minimizing the adverse side effects.     

Microscale Vortex-assisted Electroporator for Sequential Molecular Delivery

Electroporation has received increasing attention in the past years, because it is a very powerful technique for physically introducing non-permeant exogenous molecular probes into cells. This work reports a microfluidic electroporation platform capable of performing multiple molecule delivery to mammalian cells with precise and molecular-dependent parameter control. The system’s ability to isolate cells with uniform size distribution allows for less variation in electroporation efficiency per given electric field strength; hence enhanced sample viability. Moreover, its process visualization feature allows for observation of the fluorescent molecular uptake process in real-time, which permits prompt molecular delivery parameter adjustments in situ for efficiency enhancement. To show the vast capabilities of the reported platform, macromolecules with different sizes and electrical charges (e.g., Dextran with MW of 3,000 and 70,000 Da) were delivered to metastatic breast cancer cells with high delivery efficiencies (>70%) for all tested molecules. The developed platform has proven its potential for use in the expansion of research fields where on-chip electroporation techniques can be beneficial.     

Preparation of Irinotecan-Loaded Folate-Targeted Liposome for Tumor Targeting Delivery and Its Antitumor Activity

The purpose of this study was to investigate the in vivo distribution and antitumor activity of irinotecan (camptothecin (CPT)-11)-loaded folate-targeted liposome (F-Lip) in tumor-bearing mice following i.v. administration. Folate–poly(ethylene glycol)–distearoylphosphatidylcholine (FA–PEG–DSPE) was synthesized by amide reaction of DSPE–PEG–NH₂ and FA. F-Lip modified by FA–PEG–DSPE was prepared by an ammonium sulfate gradient. The mean particle size and entrapment efficiency of F-Lip with negative charge were 197.8 ± 4.58 nm and 91.39 ± 2.34 %, respectively. The distributions of CPT-11 and SN-38 in the tumor after i.v. administration of F-Lip, CPT-11-loaded liposomes (C-Lip), and CPT-11 injection (C-Inj) were far greater with the F-Lip group in comparison to the C-Inj and C-Lip, which might contribute to folate-meditated targeting uptake by the folate receptor on the surface of the tumor cells. The uptake of CPT-11 in the liver and rectum for two liposome groups were all markedly increased as compared to the C-Inj. Moreover, F-Lip exhibited a dose-dependent tumor growth inhibition and superior anticancer activity to C-Lip and C-Inj after i.v. administration. It also showed no significant body weight loss and much lower toxicity on the center immune organs. Therefore, F-Lip may be presented as potential candidates for tumor targeting drug delivery.KEY WORDS: cancer targeting, CPT-11, folate, liposomes, SN-38     

紫杉醇载药体系及其抗肿瘤活性和临床应用

紫杉醇是临床上常用的抗肿瘤药物,主要作用机制为促进细胞微管聚合并抑制微管解聚,导致细胞纺锤体失去正常功能,抑制肿瘤细胞的有丝分裂,进而诱导细胞凋亡,目前已被用于治疗卵巢癌、乳腺癌、肺癌等恶性肿瘤。紫杉醇难溶于水,临床上常采用聚氧乙烯蓖麻油和乙醇助溶,而聚氧乙烯蓖麻油易引起过敏反应。为提高紫杉醇在水中的溶解度,减少毒副作用的发生,并提高紫杉醇的抗肿瘤活性,国内外学者对紫杉醇的不同载药体系、制剂剂型及临床用药方式等进行了广泛的研究。现在,纳米技术与生物医学结合产生的纳米载药体系已经用于改善紫杉醇的水溶性和临床疗效。     

叶酸受体介导的负载紫杉醇纳米药物输送系统的制备

目的:构建靶向肿瘤组织的药物输送系统,是解决目前临床肿瘤化疗问题的有效途径之一.我们拟开展叶酸受体介导的负载紫杉醇纳米药物输送系统的制备及其表征.方法:以丁二酰化肝素为载体,通过碳二亚胺法将叶酸和丁二酰化肝素连接,制备肝素-叶酸偶联物,然后通过物理方法将紫杉醇包裹在肝素-叶酸偶联物中,在水溶性条件下体系自组装成肝素-叶酸-紫杉醇纳米粒.应用核磁共振氢谱(1H NMR),动态光散射(DLS)和扫描电子显微镜(SEM)对构建的纳米药物结构进行表征,同时观测其在水溶性条件下的自组装行为.结果:成功制备了肝素-叶酸-紫杉醇纳米药物输送系统,检测表明药物系统带有8.5％(w/w)的叶酸并负载9.6％(w/w)的药物,SEM检测表明形成了球状的纳米颗粒,DLS表明粒子的粒径在了86 nm左右.结论:我们成功制备了叶酸受体介导的负载紫杉醇的纳米药物输送系统,在进一步开展的生物活性的检测中,希望通过叶酸受体的靶向作用,引导药物定向分布在肿瘤组织,从而提高化疗药物的治疗效果同时降低其对正常细胞的毒副作用,为开发新型靶向药物输送系统提供基础.     

Influence of Liposome Composition on Plasmid DNA Delivery to Eukaryotic Cells

Russian Journal of Bioorganic Chemistry - Gene therapy is a promising method for the treatment of various diseases by introducing therapeutic nucleic acids, for the delivery of which cationic...     

Chitosan and Glyceryl Monooleate Nanostructures Containing Gemcitabine: Potential Delivery System for Pancreatic Cancer Treatment

The objectives of this study are to enhance cellular accumulation of gemcitabine with chitosan/glyceryl monooleate (GMO) nanostructures, and to provide significant increase in cell death of human pancreatic cancer cells in vitro. The delivery system was prepared by a multiple emulsion solvent evaporation method. The nanostructure topography, size, and surface charge were determined by atomic force microscopy (AFM), and a zetameter. The cellular accumulation, cellular internalization and cytotoxicity of the nanostructures were evaluated by HPLC, confocal microscopy, or MTT assay in Mia PaCa-2 and BxPC-3 cells. The average particle diameter for 2% and 4% (w/w) drug loaded delivery system were 382.3 ± 28.6 nm, and 385.2 ± 16.1 nm, respectively with a surface charge of +21.94 ± 4.37 and +21.23 ± 1.46 mV. The MTT cytotoxicity dose-response studies revealed the placebo at/or below 1 mg/ml has no effect on MIA PaCa-2 or BxPC-3 cells. The delivery system demonstrated a significant decrease in the IC50 (3 to 4 log unit shift) in cell survival for gemcitabine nanostructures at 72 and 96 h post-treatment when compared with a solution of gemcitabine alone. The nanostructure reported here can be resuspended in an aqueous medium that demonstrate increased effective treatment compared with gemcitabine treatment alone in an in vitro model of human pancreatic cancer. The drug delivery system demonstrates capability to entrap both hydrophilic and hydrophobic compounds to potentially provide an effective treatment option in human pancreatic cancer.     

Mesoporous Silica Nanoparticles for Cancer Therapy: Energy-Dependent Cellular Uptake and Delivery of Paclitaxel to Cancer Cells

Biocompatible mesoporous silica nanoparticles, containing the fluorescence dye fluorescein isothiocyanate (FITC), provide a promising system to deliver hydrophobic anticancer drugs to cancer cells. In this study, we investigated the mechanism of uptake of fluorescent mesoporous silica nanoparticles (FMSN) by cancer cells. Incubation with FMSN at different temperatures showed that the uptake was higher at 37°C than at 4°C. Metabolic inhibitors impeded uptake of FMSN into cells. The inhibition of FMSN uptake by nocodazole treatment suggests that microtubule functions are required. We also report utilization of mesoporous silica nanoparticles to deliver a hydrophobic anticancer drug paclitaxel to PANC-1 cancer cells and to induce inhibition of proliferation. Mesoporous silica nanoparticles may provide a valuable vehicle to deliver hydrophobic anticancer drugs to human cancer cells.     

Intratumoral Delivery of Paclitaxel in Solid Tumor from Biodegradable Hyaluronan Nanoparticle Formulations

In the current study, novel paclitaxel-loaded cross-linked hyaluronan nanoparticles were engineered for the local delivery of paclitaxel as a prototype drug for cancer therapy. The nanoparticles were prepared using a desolvation method with polymer cross-linking. In vitro cytotoxicity studies demonstrated that less than 75% of the MDA-MB-231 and ZR-75-1 breast cancer cells were viable after 2-day exposure to paclitaxel-loaded hyaluronan nanoparticles or free paclitaxel, regardless of the dose. These results suggest that hyaluronan nanoparticles maintain the pharmacological activity of paclitaxel and efficiently deliver it to the cells. Furthermore, in vivo administration of the drug-loaded nanoparticles via direct intratumoral injection to 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumor in female rats was studied. The paclitaxel-loaded nanoparticles treated group showed effective inhibition of tumor growth in all treated rats. Interestingly, there was one case of complete remission of tumor nodule and two cases of persistent reduction of tumor size that was observed on subsequent days. In the case of free paclitaxel-treated group, the mean tumor volume increased almost linearly (R ² = 0.93) with time to a size that was 4.9-fold larger than the baseline volume at 57 days post-drug administration. Intratumoral administration of paclitaxel-loaded hyaluronan nanoparticles could be a promising treatment modality for solid mammary tumors.     

Inducing Controlled Release and Increased Tumor-Targeted Delivery of Chlorambucil via Albumin/Liposome Hybrid Nanoparticles

Liposomes possess good biocompatibility and excellent tumor-targeting capacity. However, the rapid premature release of lipophilic drugs from the lipid bilayer of liposomes has negative effect on the tumor-targeted drug delivery of liposomes. In this study, a lipophilic antitumor drug—chlorambucil (CHL)—was encapsulated into the aqueous interior of liposomes with the aid of albumin to obtain the CHL-loaded liposomes/albumin hybrid nanoparticles (CHL-Hybrids). The in vitro accumulative release rate of CHL from CHL-Hybrids was less than 50% within 48 h, while the accumulative CHL release was more than 80% for CHL-loaded liposomes (CHL-Lip). After intravenous injection into rats, the half-life (t _1/2β = 5.68 h) and maximum blood concentration (C _max = 4.58 μg/mL) of CHL-Hybrids were respectively 1.1 times and 3.5 times higher than that of CHL-Lip. In addition, CHL-Hybrids had better tumor-targeting capacity for it significantly increased the drug accumulation in B16F10 tumors, which contributed to the significantly control of tumor growth compared with CHL-Lip. Furthermore, CHL-Hybrid-treated B16F10 melanoma-bearing mice displayed the longest median survival time of 30.0 days among all the treated groups. Our results illustrated that the proposed hybrids drug delivery system would be a promising strategy to maintain the controlled release of lipophilic antitumor drugs from liposomes and simultaneously facilitate the tumor-targeted drug delivery.     

紫杉醇脂质体联合顺铂同步放疗对老年宫颈癌有较好疗效

本研究将178例具有危险因素的老年宫颈癌术后患者随机分为研究组和对照组各89例,对照组给予紫杉醇联合顺铂同步放化疗方案,研究组给予紫杉醇脂质体联合顺铂同步放化疗方案,观察2组患者治疗期间的毒副反应及1年、2年、3年生存率、局部复发率和远处转移率,以期探讨老年宫颈癌患者术后不同化疗方案联合同步放疗的有效性和安全性。研究结果表明:研究组骨髓抑制、消化道反应、肝肾功能异常、脱发发生率低于对照组(p<0.05);研究组1年、2年、3年生存率与对照组相比较均无统计学差异(p>0.05);研究组与对照组1年、2年、3年局部复发率和远处转移率相比较差异均无统计学意义(p>0.05)。本研究初步结论认为,老年宫颈癌患者术后采用紫杉醇脂质体联合顺铂同步放化疗方案更为安全有效,采用紫杉醇脂质体代替紫杉醇注射液值得在临床推广应用。     

A New Approach for the Discrimination of Mixed Data

A new procedure for the discrimination of mixed data is presented. The method allows the application of well-known discriminators after defining new (continuous) variables from the a-posteriori-probabilities. Some outlooks and an example from medical diagnostics are given.     

Combined Delivery of Paclitaxel and Tanespimycin via Micellar Nanocarriers: Pharmacokinetics,Efficacy and Metabolomic Analysis

Background

Despite the promising anticancer efficacy observed in preclinical studies, paclitaxel and tanespimycin (17-AAG) combination therapy has yielded meager responses in a phase I clinical trial. One serious problem associated with paclitaxel/17-AAG combination therapy is the employment of large quantities of toxic organic surfactants and solvents for drug solubilization. The goal of this study was to evaluate a micellar formulation for the concurrent delivery of paclitaxel and 17-AAG in vivo.

Methodology/Principal Findings

Paclitaxel/17-AAG-loaded micelles were assessed in mice bearing human ovarian tumor xenografts. Compared with the free drugs at equivalent doses, intravenous administration of paclitaxel/17-AAG-loaded micelles led to 3.5- and 1.7-fold increase in the tumor concentrations of paclitaxel and 17-AAG, respectively, without significant altering drug levels in normal organs. The enhanced tumor accumulation of the micellar drugs was further confirmed by the whole-body near infrared imaging using indocyanine green-labeled micelles. Subsequently, the anticancer efficacy of paclitaxel/17-AAG-loaded micelles was examined in comparison with the free drugs (weekly 20 mg/kg paclitaxel, twice-weekly 37.5 mg/kg 17-AAG). We found that paclitaxel/17-AAG-loaded micelles caused near-complete arrest of tumor growth, whereas the free drug-treated tumors experienced rapid growth shortly after the 3-week treatment period ended. Furthermore, comparative metabolomic profiling by proton nuclear magnetic resonance revealed significant decrease in glucose, lactate and alanine with simultaneous increase in glutamine, glutamate, aspartate, choline, creatine and acetate levels in the tumors of mice treated with paclitaxel/17-AAG-loaded micelles.

Conclusions/Significance

We have demonstrated in the current wok a safe and efficacious nano-sized formulation for the combined delivery of paclitaxel and 17-AAG, and uncovered unique metabolomic signatures in the tumor that correlate with the favorable therapeutic response to paclitaxel/17-AAG combination therapy.     

Sequential Cytokine-Induced Killer Cell Immunotherapy Enhances the Efficacy of the Gemcitabine Plus Cisplatin Chemotherapy Regimen for Metastatic Nasopharyngeal Carcinoma

In this study, we investigated the efficacy of sequential cytokine-induced killer cell (CIK) immunotherapy with gemcitabine plus cisplatin (GC) regimen chemotherapy in metastatic nasopharyngeal carcinoma (NPC) patients. Between September 2006 and April 2010, 222 NPC patients with distant metastasis after radiotherapy completion were retrospectively analyzed: 112 patients received 4–6 cycles of GC chemotherapy at 4-week intervals, followed by at least 4 cycles of CIK immunotherapy at 2-week intervals (GC+CIK group); the remaining 110 patients received 4–6 cycles of GC chemotherapy alone (GC group). The evaluation of long-term efficacy showed that the progression-free survival (PFS) rate was significantly higher in the GC+CIK group (log-rank test; p = 0.009), as was the overall survival (OS) rate (p = 0.006). In conclusion, sequential CIK treatment may be effective in enhancing the therapeutic efficacy of GC chemotherapy for metastatic NPC patients. This study provides a basis for alternative therapeutic strategies for metastatic NPC.     

Microcapsules and Transdermal Patch: A Comparative Approach for Improved Delivery of Antidiabetic Drug

Glibenclamide (GL)-loaded microcapsules (MC) and transdermal patches (TDP) were formulated and in vitro and in vivo parameters compared to find out the best route of drug administration. The formulation TDP1 having a drug–polymer ratio 1:1 showed comparatively higher GL release and better permeation across mice skin (p < 0.05). From the comparative study, it was concluded that the transdermal system of GL produced better improvement compared to oral microcapsule administration (p < 0.05). The transdermal system exhibited comparatively slow and continuous supply of GL at a desired rate to systemic circulation avoiding metabolism, which improved day-to-day glycemic control in diabetic subjects. Transdermal system of GL exhibited better control of hyperglycemia and prolonged plasma half-life by transdermal systems (9.6 ± 1.2 h) in comparison with oral microcapsule (5.84 ± 2.1 h), indicating that the drug, when administered by transdermal systems, will remain in the body for a longer period. From the glucose tolerance test, transdermal route effectively maintained the normoglycemic levels in contrast to the oral group (MC1), which produced remarkable hypoglycemia ranging from −12.6 ± 2.1% to −18 ± 2.3%. The significantly high (p < 0.05) area under the curve values observed with transdermal system (1,346.2 ± 92.3 ng ml⁻¹ h⁻¹) also indicate increased bioavailability of the drug from these systems compared to the oral route (829.8 ± 76.4 ng ml⁻¹ h⁻¹).     

The Effects of pH and Intraliposomal Buffer Strength on the Rate of Liposome Content Release and Intracellular Drug Delivery

Targeted liposomal drug formulations may enter cells by receptor-mediated endocytosis and then traffick by membrane flow into acidic intracellular compartments. In order to understand the impact of these intracellular pH changes on liposomal drug unloading, the effect of pH on the release from folate-targeted liposomes of three model compounds with distinct pH dependencies was examined. 5(6)-carboxyfluorescein, which titrates from its anionic to uncharged form following internalization by KB cells, displays strong endocytosis-dependent release, since only its uncharged (endosomal) form is membrane permeable. Endocytosis-triggered unloading of drugs of this sort is enhanced by encapsulating the drug in a weak buffer at neutral pH, so that acidification of the intraliposomal compartment following cellular uptake can occur rapidly. Sulforhodamine B, in contrast, retains both anionic and cationic charges at endosomal pH (~pH 5), and consequently, escapes the endosomes only very slowly. Doxorubicin, which is commonly loaded into liposomes in its membrane-impermeable (cationic) form using an acidic buffer, still displays endocytosis-triggered unloading, since sufficient uncharged doxorubicin remains at endosomal pHs to allow rapid re-equilibration of the drug according to the new proton gradient across the membrane. In this case, when the extraliposomal [H⁺] increases 250-fold from 4 × 10^–8 M (pH 7.4, outside the cell) to 10^–5 M (pH 5, inside the endosome), the ratio of doxorubicin inside to outside the liposome must decrease by a factor of 250. Therefore, the collapse of the transliposomal pH gradient indirectly drives an efflux of the drug molecule from the liposome. Since a change in intraliposomal pH is not required to unload drugs of this type, the intraliposomal compartment can be buffered strongly at acidic pH to prevent premature release of the drug outside the cell. In summary, pH triggered release of liposome-encapsulated drugs can be achieved both with drugs that increase as well as decrease their membrane permeabilities upon acidification, as long as the intraliposomal buffer strength and pH is rationally selected.     

Ratiometric Raman spectroscopy for quantification of protein oxidative damage

A novel ratiometric Raman spectroscopic (RMRS) method has been developed for quantitative determination of protein carbonyl levels. Oxidized bovine serum albumin (BSA) and oxidized lysozyme were used as model proteins to demonstrate this method. The technique involves conjugation of protein carbonyls with dinitrophenyl hydrazine (DNPH), followed by drop coating deposition Raman spectral acquisition (DCDR). The RMRS method is easy to implement because it requires only one conjugation reaction, uses a single spectral acquisition, and does not require sample calibration. Characteristic peaks from both protein and DNPH moieties are obtained in a single spectral acquisition, allowing the protein carbonyl level to be calculated from the peak intensity ratio. Detection sensitivity for the RMRS method is approximately 0.33 pmol carbonyl per measurement. Fluorescence and/or immunoassay-based techniques only detect a signal from the labeling molecule and, thus, yield no structural or quantitative information for the modified protein, whereas the RMRS technique allows protein identification and protein carbonyl quantification in a single experiment.     

Sequential Activation of Metabolic Pathways: a Dynamic Optimization Approach

The regulation of cellular metabolism facilitates robust cellular operation in the face of changing external conditions. The cellular response to this varying environment may include the activation or inactivation of appropriate metabolic pathways. Experimental and numerical observations of sequential timing in pathway activation have been reported in the literature. It has been argued that such patterns can be rationalized by means of an underlying optimal metabolic design. In this paper we pose a dynamic optimization problem that accounts for time-resource minimization in pathway activation under constrained total enzyme abundance. The optimized variables are time-dependent enzyme concentrations that drive the pathway to a steady state characterized by a prescribed metabolic flux. The problem formulation addresses unbranched pathways with irreversible kinetics. Neither specific reaction kinetics nor fixed pathway length are assumed. In the optimal solution, each enzyme follows a switching profile between zero and maximum concentration, following a temporal sequence that matches the pathway topology. This result provides an analytic justification of the sequential activation previously described in the literature. In contrast with the existent numerical approaches, the activation sequence is proven to be optimal for a generic class of monomolecular kinetics. This class includes, but is not limited to, Mass Action, Michaelis–Menten, Hill, and some Power-law models. This suggests that sequential enzyme expression may be a common feature of metabolic regulation, as it is a robust property of optimal pathway activation.