Tumor targeting using liposomal antineoplastic drugs

Enhanced apoptosis and mitochondrial cell death by paclitaxel-loaded TPP-TPGS1000-functionalized nanoemulsion

Background: The present research was designed to develop a nanoemulsion (NE) of triphenylphosphine-D-α-tocopheryl-polyethylene glycol succinate (TPP-TPGS₁₀₀₀) and paclitaxel (PTX) to effectively deliver PTX to improve breast cancer therapy. Materials & methods: A quality-by-design approach was applied for optimization and in vitro and in vivo characterization were performed. Results: The TPP-TPGS₁₀₀₀-PTX-NE enhanced cellular uptake, mitochondrial membrane depolarization and G₂M cell cycle arrest compared with free-PTX treatment. In addition, pharmacokinetics, biodistribution and in vivo live imaging studies in tumor-bearing mice showed that TPP-TPGS₁₀₀₀-PTX-NE had superior performance compared with free-PTX treatment. Histological and survival investigations ascertained the nontoxicity of the nanoformulation, suggesting new opportunities and potential to treat breast cancer. Conclusion: TPP-TPGS₁₀₀₀-PTX-NE improved the efficacy of breast cancer treatment by enhancing its effectiveness and decreasing drug toxicity.

Overview of polyethylene glycol-based materials with a special focus on core-shell particles for drug delivery application

Polyethylene glycols (PEG) are water-soluble nonionic polymeric molecules. PEG and PEG-based materials are used for various important applications such as solvents, adhesives, adsorbents, drug delivery agents, tissue engineering scaffolds, etc. The coating of nanoparticles with PEG forms core-shell nanoparticles. The PEG-based core-shell nanoparticles are synthesized for the development of high-quality drug delivery systems. In the present review, we first explained the basics and various applications of PEGs and PEG-based composites materials and then concentrated on the PEG-based core-shell nanoparticles for biomedical applications specifically their use in drug delivery.

Ex vivo-generated dendritic cell-based vaccines in melanoma: the role of nanoparticulate delivery systems

Melanoma is a poor immunogenic cancer and many treatment strategies have been used to enhance specific or nonspecific immunity against it. Dendritic cell (DC)-based cancer vaccine is the most effective therapies that have been used so far. Meanwhile, the efficacy of DC-based immunotherapy relies on critical factors relating to DCs such as the state of maturation and proper delivery of antigens. In this regard, the use of nanoparticulate delivery systems for effective delivery of antigen to ex vivo-generated DC-based vaccines that also poses adjuvanticity would be an ideal approach. In this review article, we attempt to summarize the role of different types of nanoparticulate antigen delivery systems used in the development of ex vivo-generated DC-based vaccines against melanoma and describe their adjuvanticity in mediation of DC maturation, cytoplasmic presentation of antigens to MHC class I molecules, which led to potent antigen-specific immune responses. As were represented, cationic liposomes were the most used approach, which suggest its potential applicability as delivery systems for further experiments in combination with either adjuvants or monoclonal antibodies.

Updates on the use of liposomes for active tumor targeting in cancer therapy

In the development of cancer chemotherapy, besides the discovery of new anticancer drugs, a variety of nanocarrier systems for the delivery of previously developed and new chemotherapeutic drugs have currently been explored. Liposome is one of the most studied nanocarrier systems because of its biodegradability, simple preparation method, high efficacy and low toxicity. To make the best use of this vehicle, a number of multifunctionalized liposomal formulations have been investigated. The objective of this review is to summarize the current development of novel active targeting liposomal formulations, and to give insight into the challenges and future direction of the field. The recent studies in active targeting liposomes suggest the great potential of precise targeted anticancer drug delivery in cancer therapeutics.

23 Full Factorial Model for Particle Size Optimization of Methotrexate Loaded Chitosan Nanocarriers: A Design of Experiments (DoE) Approach

Purpose

To build and inquire a statistically significant mathematical model for manufacturing methotrexate loaded chitosan nanoparticles (CsNP) of desired particle size. The study was also performed to evaluate the effect of formulation variables in the explored design space.

Method

Ionotropic gelation technique was followed for chitosan nanocarriers by changing formulation variables suggested as per Design Expert software. Altering the levels of Chitosan, tripolyphosphate, methotrexate by 2³ factorial design served the purpose. The CsNP were characterized for nanocarrier formation, particle size, and statistical analysis. Then mathematical model was statistically analyzed for fabricating desired formulation having particle size less than 200nm.

Results

FT-IR, XRD reports confirmed the structural change in chitosan which lead to the formation of CsNP. For particle size, linear model was found to be best fit to explain effect of variables. Besides, high R² (0.9958) defends the constancy of constructed model. Chitosan exhibited higher t-value in Pareto chart and a p-value <0.0001. Based on maximum desirability, optimization was performed and amount of variables for preparing CsNP of 180nm was predicted. The experiment was carried out with software suggested combination and particle size was found to be 176±4nm.

Conclusion

Low p-value endorsed the greater dominance of chitosan on particle size. Good model adequacy and small percentage error between predicted and experimented value established the reliability of constructed model for robust preparation of CsNP.

Design, synthesis and applications of core-shell, hollow core, and nanorattle multifunctional nanostructures

With the evolution of nanoscience and nanotechnology, studies have been focused on manipulating nanoparticle properties through the control of their size, composition, and morphology. As nanomaterial research has progressed, the foremost focus has gradually shifted from synthesis, morphology control, and characterization of properties to the investigation of function and the utility of integrating these materials and chemical sciences with the physical, biological, and medical fields, which therefore necessitates the development of novel materials that are capable of performing multiple tasks and functions. The construction of multifunctional nanomaterials that integrate two or more functions into a single geometry has been achieved through the surface-coating technique, which created a new class of substances designated as core-shell nanoparticles. Core-shell materials have growing and expanding applications due to the multifunctionality that is achieved through the formation of multiple shells as well as the manipulation of core/shell materials. Moreover, core removal from core-shell-based structures offers excellent opportunities to construct multifunctional hollow core architectures that possess huge storage capacities, low densities, and tunable optical properties. Furthermore, the fabrication of nanomaterials that have the combined properties of a core-shell structure with that of a hollow one has resulted in the creation of a new and important class of substances, known as the rattle core-shell nanoparticles, or nanorattles. The design strategies of these new multifunctional nanostructures (core-shell, hollow core, and nanorattle) are discussed in the first part of this review. In the second part, different synthesis and fabrication approaches for multifunctional core-shell, hollow core-shell and rattle core-shell architectures are highlighted. Finally, in the last part of the article, the versatile and diverse applications of these nanoarchitectures in catalysis, energy storage, sensing, and biomedicine are presented.

Liposomal polychemotherapy improves adrenocortical carcinoma treatment in a preclinical rodent model

Owing to high relapse rates and early metastatic spread, prognosis in adrenocortical carcinoma (ACC) patients remains poor, highlighting the importance of developing new treatment alternatives for them. Recently, polychemotherapy regimens including etoposide, doxorubicin, and cisplatin together with mitotane (EDP-M) have been defined as the standard treatment for late-stage disease patients. Nevertheless, the administration of conventional cytostatic drugs is associated with severe and dose-limiting side effects. In an attempt to optimize existing clinical treatment regimens, in this study, we investigated the therapeutic efficacy of EDP-M in comparison with that of a paclitaxel-modified scheme (paclitaxel, doxorubicin, cisplatin plus mitotane (PDP-M)) in preclinical in vitro and in vivo models. In addition, based on an extraordinary uptake phenomenon of liposomes in ACC cells, we further evaluated liposomal variants of these protocols (etoposide, liposomal doxorubicin, liposomal cisplatin plus mitotane (LEDP-M) and nab-paclitaxel, liposomal doxorubicin, liposomal cisplatin plus mitotane (LPDP-M)). In vitro, PDP-M was more potent in the induction of apoptosis and inhibition of cell viability as well as cell proliferation than EDP-M. Following the administration of a single therapeutic cycle, we further demonstrated that LEDP-M and LPDP-M exerted significant antitumoral effects in vivo, which were not as evident upon EDP-M and PDP-M treatments. These results were confirmed in a long-term experiment, in which the highest and sustained antitumoral effects were observed for LEDP-M. In summary, liposomal cytostatic substances could represent a promising option that deserves testing in appropriate clinical protocols for the treatment of ACC patients.

Current trends in the use of liposomes for tumor targeting

The use of liposomes for drug delivery began early in the history of pharmaceutical nanocarriers. These nanosized, lipid bilayered vesicles have become popular as drug delivery systems owing to their efficiency, biocompatibility, nonimmunogenicity, enhanced solubility of chemotherapeutic agents and their ability to encapsulate a wide array of drugs. Passive and ligand-mediated active targeting promote tumor specificity with diminished adverse off-target effects. The current field of liposomes focuses on both clinical and diagnostic applications. Recent efforts have concentrated on the development of multifunctional liposomes that target cells and cellular organelles with a single delivery system. This review discusses the recent advances in liposome research in tumor targeting.

Preparation, physicochemical characterization, and cell viability evaluation of long-circulating and pH-sensitive liposomes containing ursolic acid

Cancer is one of the leading causes of death worldwide. Although several drugs are used clinically, some tumors either do not respond or are resistant to the existing pharmacotherapy, thus justifying the search for new drugs. Ursolic acid (UA) is a triterpene found in different plant species that has been shown to possess significant antitumor activity. However, UA presents a low solubility in aqueous medium, which presents a barrier to its biological applications. In this context, the use of liposomes presents a promising strategy to deliver UA and allow for its intravenous administration. In this work, long-circulating and pH-sensitive liposomes containing UA (SpHL-UA) were developed, and their chemical and physicochemical properties were evaluated. SpHL-UA presented adequate properties, including a mean diameter of 191.1 ± 6.4 nm, a zeta potential of 1.2 ± 1.4 mV, and a UA entrapment of 0.77 ± 0.01 mg/mL. Moreover, this formulation showed a good stability after having been stored for 2 months at 4 °C. The viability studies on breast (MDA-MB-231) and prostate (LNCaP) cancer cell lines demonstrated that SpHL-UA treatment significantly inhibited cancer cell proliferation. Therefore, the results of the present work suggest the applicability of SpHL-UA as a new and promising anticancer formulation.

Metal-based nanoparticle interactions with the nervous system: the challenge of brain entry and the risk of retention in the organism

This review of metal-based nanoparticles focuses on factors influencing their distribution into the nervous system, evidence they enter brain parenchyma, and nervous system responses. Gold is emphasized as a model metal-based nanoparticle and for risk assessment in the companion review. The anatomy and physiology of the nervous system, basics of colloid chemistry, and environmental factors that influence what cells see are reviewed to provide background on the biological, physical-chemical, and internal milieu factors that influence nervous system nanoparticle uptake. The results of literature searches reveal little nanoparticle research included the nervous system, which about equally involved in vitro and in vivo methods, and very few human studies. The routes of uptake into the nervous system and mechanisms of nanoparticle uptake by cells are presented with examples. Brain nanoparticle uptake inversely correlates with size. The influence of shape has not been reported. Surface charge has not been clearly shown to affect flux across the blood-brain barrier. There is very little evidence for metal-based nanoparticle distribution into brain parenchyma. Metal-based nanoparticle disruption of the blood-brain barrier and adverse brain changes have been shown, and are more pronounced for spheres than rods. Study concentrations need to be put in exposure contexts. Work with dorsal root ganglion cells and brain cells in vitro show the potential for metal-based nanoparticles to produce toxicity. Interpretation of these results must consider the ability of nanoparticles to distribute across the barriers protecting the nervous system. Effects of the persistence of poorly soluble metal-based nanoparticles are of particular concern.

Liposomal doxorubicin-based treatment in a preclinical model of adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare endocrine tumor entity with poor prognosis. Medical treatment is limited to common cytotoxic agents, which are associated with low treatment responses. Thus, lack of therapeutic efficacy demands innovative treatment options for patients with advanced ACC. Recently, we have developed and characterized anti-IGF1 receptor (IGF1-R) immunoliposomes (SSLD-1H7) for the treatment of neuroendocrine tumors of the gastroenteropancreatic system. As previous results indicated putative applicability also for other IGF1-R-overexpressing tumor entities, we initiated testing of liposomal preparations in in vitro and in vivo models of ACC. Adrenocortical NCIh295 cells were used for in vitro association studies with different liposomal formulations. Thereby, flow cytometry revealed high cellular association and internalization of anti-IGF1-R immunoliposomes (soy phosphatidylcholine (SPC)/cholesterol (Chol)-polyethyleneglycol (PEG)-1H7, 50.1±2.2%). Moreover, internalization of pegylated liposomes (SPC/Chol-PEG, 57.1±2.4%) and an even higher uptake of plain liposomes (84.6±0.8%; P<0.0001) were detectable in adrenocortical tumor cells. In vivo, liposomal treatments were investigated on NCIh295 tumor xenografts in pharmacokinetic and therapeutic experiments. A significant reduction in tumor size was detectable in NCIh295 tumor-bearing mice after a single treatment with SSLD-1H7 (0.89±0.15 cm; P=0.006) and a diminished efficacy for SSLD-PEG+ (1.01±0.19 cm; P=0.04) in comparison with untreated controls (1.5±0.0 cm). Thus, anti-IGF1-R immunoliposomes have been successfully tested in vitro and in vivo in a preclinical model for ACCs and could, therefore, represent a promising therapeutic approach for this tumor entity. Moreover, a combination of mitotane plus liposomally encapsulated cytostatic agents instead of free drugs could also be an interesting novel treatment option for ACC in the future.

Optimizing Druggability through Liposomal Formulations: New Approaches to an Old Concept

Developing innovative delivery strategies remains an ongoing task to improve both efficacy and safety of drug-based therapy. Nanomedicine is now a promising field of investigation, rising high expectancies for treating various diseases such as malignancies. Putting drugs into liposome is an old story that started in the late 1960s. Because of the near-total biocompatibility of their lipidic bilayer, liposomes are less concerned with the safety issue related to the possible long-term accumulation in the body of most nanoobjects currently developed in nanomedicine. Additionally, novel techniques and recent efforts to achieve better stability (e.g., through sheddable coating), combined with a higher selectivity towards target cells (e.g., by anchoring monoclonal antibodies or incorporating phage fusion protein), make new liposomal drugs an attractive and challenging opportunity to improve clinical outcome in a variety of disease. This review covers the physicochemistry of liposomes and the recent technical improvements in the preparation of liposome-encapsulated drugs in regard to the scientific and medical stakes.

Toxicological considerations when creating nanoparticle-based drugs and drug delivery systems

INTRODUCTION

The biggest challenge faced by the scientific community involved in drug development is to deliver safe and effective dosage of drugs without causing systemic toxicity. Therefore, novel nano-based delivery vehicles specifically targeting tumors but not normal tissues are urgently needed.

AREAS COVERED

Nanoparticles have beneficial aspects but can be toxic themselves, which is always a concern for any drug or delivery agent. This review examines and details the toxicological aspects that should be considered when planning to use nanoparticles in animals or in man for drug delivery or imaging. Subjects discussed in this review include i) overviews of applications of various nanoparticles for drug delivery and imaging; ii) toxicological aspects to consider when selecting particular nanoparticles for use in various applications in animals or man; iii) hurdles faced when examining nanoparticle toxicity; and iv) current approaches for assessing nanoparticle toxicity.

EXPERT OPINION

Nanotechnology has significant potential for advancing therapeutic efficacy and imaging in cancer; however, these agents can be toxic. Therefore, toxicity needs to be considered when selecting nanoparticles for a particular application. Methods for assessing nanoparticle toxicity need to be improved and standardized across all nanotechnology platforms in order to speed up the application of nanoparticle use in humans.

Proinflammatory effects of bare and PEGylated ORMOSIL-, PLGA- and SUV-NPs on monocytes and PMNs and their modulation by f-MLP

AIMS

We wanted to test the proinflammatory effects of vinyltriethoxysilane-based organically modified silica nanoparticles (ORMOSIL-NPs) in vitro on blood leukocytes.

MATERIALS & METHODS

Cell selectivity, cytokines/chemokines and O(2) (-) production were analyzed using nonpolyethylene glycol (PEG)ylated and PEGylated ORMOSIL-NPs, poly(lactic-co-glycolic acid) (PLGA)-NPs and small unilamellar vesicles (SUV)-NPs.

RESULTS

ORMOSIL-NPs mostly bound to monocytes while other NPs to all leukocyte types similarly. Cell capture of PEGylated-NPs decreased strongly (ORMOSIL), moderately (PLGA) and weakly (SUV). Bare ORMOSIL-NPs effectively stimulated the production of IL-1β/IL-6/TNF-α/IL-8 by monocytes and of IL-8 by polymorphonuclear leukocytes (PMNs). NP PEGylation inhibited such effects only partially. Formyl-methionine-leucine phenylalanine (f-MLP) further increased the release of cytokines/chemokines by monocytes/PMNs primed with bare and PEGylated ORMOSIL-NPs. PEGylated SUV-NPs, bare and PEGylated ORMOSIL- and PLGA-NPs sensitize PMNs and monocytes to secrete O(2) (-) upon f-MLP stimulation.

CONCLUSION

ORMOSIL-NPs are preferentially captured by circulating monocytes but stimulate both monocytes and PMNs per se or by sensitizing them to another agonist (f-MLP). PEG-coating confers stealth effects but does not completely eliminate leukocyte activation. Safe nanomedical applications require the evaluation of both intrinsic and cooperative proinflammatory potential of NPs.

Nanoimaging and neurological surgery

Over 32 million surgical procedures are performed in the United States each year. Increasingly, image guidance is used in order to aid in the surgical localization of pathology, minimization of incisions, and improvement of surgical intervention outcomes. A variety of imaging modalities using different portions of the electromagnetic spectrum are used in neurological surgery. These include wavelengths used in ultrasonography, optical, infrared, ionizing radiation, and magnetic resonance. The use of currently available image-guidance tools for neurological surgery is reviewed. Advances in nanoparticulates and their integration into the neurosurgical operating room environment are discussed.

Procoagulant properties of bare and highly PEGylated vinyl-modified silica nanoparticles

AIMS

Undesired alterations of the blood clotting balance may follow the intravascular injection of nanotherapeutics/diagnostics. Here, we tested the procoagulant activity of synthetic amorphous silica (SAS) and organically modified silica (ORMOSIL) nanoparticles (NPs) and whether a high-density polyethylene glycol coating minimizes these effects.

MATERIALS & METHODS

Hageman factor- and tissue factor-dependent activation of human blood/plasma coagulation, and binding to human monocytes, endothelial cells and platelets were quantified in vitro using naked and PEGylated ORMOSIL-NPs. Their effects were compared with those of SAS-NPs, present in many industrial products, and of poly(lactic-co-glycolic acid)- and small unilamellar vesicles-NPs, already approved for use in humans.

RESULTS

Both SAS-NPs and ORMOSIL-NPS presented a significant procoagulant activity. However, highly PEGylated ORMOSIL-NPs were particularly averse to the interaction with the soluble factors and cellular elements that may lead to intravascular blood coagulation.

CONCLUSION

Stealth, highly PEGylated ORMOSIL-NPs with a poor procoagulant activity can be used as starting blocks to design hemocompatible nanomedical-devices.

Nanotargeted radionuclides for cancer nuclear imaging and internal radiotherapy

Current progress in nanomedicine has exploited the possibility of designing tumor-targeted nanocarriers being able to deliver radionuclide payloads in a site or molecular selective manner to improve the efficacy and safety of cancer imaging and therapy. Radionuclides of auger electron-, α-, β-, and γ-radiation emitters have been surface-bioconjugated or after-loaded in nanoparticles to improve the efficacy and reduce the toxicity of cancer imaging and therapy in preclinical and clinical studies. This article provides a brief overview of current status of applications, advantages, problems, up-to-date research and development, and future prospects of nanotargeted radionuclides in cancer nuclear imaging and radiotherapy. Passive and active nanotargeting delivery of radionuclides with illustrating examples for tumor imaging and therapy are reviewed and summarized. Research on combing different modes of selective delivery of radionuclides through nanocarriers targeted delivery for tumor imaging and therapy offers the new possibility of large increases in cancer diagnostic efficacy and therapeutic index. However, further efforts and challenges in preclinical and clinical efficacy and toxicity studies are required to translate those advanced technologies to the clinical applications for cancer patients.

Antiangiogenic activity of sterically stabilized liposomes containing paclitaxel (SSL-PTX): in vitro and in vivo

The purpose of this present study was to evaluate the antiangiogenic activity of sterically stabilized liposomes containing paclitaxel (SSL-PTX). The SSL-PTX was prepared by the thin-film method. The release of paclitaxel from SSL-PTX was analyzed using a dialysis method. The effect of SSL-PTX on endothelial cell proliferation and migration was investigated in vitro. The antitumor and antiangiogenic activity of SSL-PTX was evaluated in MDA-MB-231 tumor xenograft growth in BALB/c nude mice. The release of paclitaxel from SSL-PTX was 22% within 24 h. Our in vitro results indicated that SSL-PTX could effectively inhibit the endothelial cell proliferation and migration at a concentration-dependent manner. We also observed that metronomic SSL-PTX induced marked tumor growth inhibition in MDA-MB-231 xenograft model via the antiangiogenic mechanism, unlike that in paclitaxel injection (Taxol) formulated in Cremophor EL (CrEL). Overall, our results suggested that metronomic chemotherapy with low-dose, CrEL-free SSL-PTX should be feasible and effective.

Magnetic quantum dots for multimodal imaging

Multimodal contrast agents based on highly luminescent quantum dots (QDs) combined with magnetic nanoparticles (MNPs) or ions form an exciting class of new materials for bioimaging. With two functionalities integrated in a single nanoparticle, a sensitive contrast agent for two very powerful and highly complementary imaging techniques [fluorescence imaging and magnetic resonance imaging (MRI)] is obtained. In this review, the state of the art in this rapidly developing field is given. This is done by describing the developments for four different approaches to integrate the fluorescence and magnetic properties in a single nanoparticle. The first type of particles is created by the growth of heterostructures in which a QD is either overgrown with a layer of a magnetic material or linked to a (superpara, or ferro) MNP. The second approach involves doping of paramagnetic ions into QDs. A third option is to use silica or polymer nanoparticles as a matrix for the incorporation of both QDs and MNPs. Finally, it is possible to introduce chelating molecules with paramagnetic ions (e.g., Gd-DTPA) into the coordination shell of the QDs. All different approaches have resulted in recent breakthroughs and the demonstration of the capability of bioimaging using both functionalities. In addition to giving an overview of the most exciting recent developments, the pros and cons of the four different classes of bimodal contrast agents are discussed, ending with an outlook on the future of this emerging new field.

Polyelectrolyte-induced aggregation of liposomes: a new cluster phase with interesting applications

Different charged colloidal particles have been shown to be able to self-assemble, when mixed in an aqueous solvent with oppositely charged linear polyelectrolytes, forming long-lived finite-size mesoscopic aggregates. On increasing the polyelectrolyte content, with the progressive reduction of the net charge of the primary polyelectrolyte-decorated particles, larger and larger clusters are observed. Close to the isoelectric point, where the charge of the adsorbed polyelectrolytes neutralizes the original charge of the particles' surface, the aggregates reach their maximum size, while beyond this point any further increase of the polyelectrolyte-particle charge ratio causes the formation of aggregates whose size is progressively reduced. This re-entrant condensation behavior is accompanied by a significant overcharging. Overcharging, or charge inversion, occurs when more polyelectrolyte chains adsorb on a particle than are needed to neutralize its original charge so that, eventually, the sign of the net charge of the polymer-decorated particle is inverted. The stability of the finite-size long-lived clusters that this aggregation process yields results from a fine balance between long-range repulsive and short-range attractive interactions, both of electrostatic nature. For the latter, besides the ubiquitous dispersion forces, whose supply becomes relevant only at high ionic strength, the main contribution appears due to the non-uniform correlated distribution of the charge on the surface of the polyelectrolyte-decorated particles ('charge-patch' attraction). The interesting phenomenology shown by these system has a high potential for biotechnological applications, particularly when the primary colloidal particles are bio-compatible lipid vesicles. Possible applications of these systems as multi-compartment vectors for the simultaneous intra-cellular delivery of different pharmacologically active substances will be briefly discussed.

Influence of liposomal clodronate upon peritoneal macrophages in rats

AIM: To explore the way of preparing liposomal clodronate and to investigate its influence of liposomal clodronate, upon peritoneal macrophages in rats.

METHODS: Liposomal clodronate was prepared by means of thin film; the peritoneal macrophages were obtained from rats. After exposure to different concentrations of LC (50, 100, 150 µmol/L), contents of NO, O₂^- and H₂O₂ were determined by MTT and neutral red colorimetry to evaluate the function of peritoneal macrophages.

RESULTS: MTT colorimetry showed that the growth of peritoneal macrophages were markedly depressed with different concentrations of liposomal clodronate (P < 0.01), neutral red colorimetry indicated the function of phagocytosis was manifestly restrained, and the inhibition ratio were 17.4%, 25.8% and 38.0%, respectively. The ability of secreting NO and O₂^- by peritoneal macrophages was significantly inhibited (48.398 ± 0.667, 27.664 ± 0.566, 25.626 ± 0.184 vs 91.714 ± 1.726; 0.289 ± 0.017, 0.256 ± 0.013, 0.216 ± 0.003 vs 0.342 ± 0.022, all P < 0.05). The ability of secreting H₂O₂ by peritoneal macrophages was inhibited obviously at 100 µmol/L and 150 µmol/L (0.261 ± 0.002, 0.213 ± 0.015 vs 0.277 ± 0.003, all P < 0.05).

CONCLUSION: Liposomal clodronate could inhibit the function of peritoneal macrophages in rats.