Lymphatic transport of liposome-encapsulated agents: effects of liposome size following intraperitoneal administration

Development of a Supramolecular Hydrogel for Intraperitoneal Injections

Local intraperitoneal drug administration is considered a challenging drug delivery route. The therapeutic efficiency is low, mainly due to rapid clearance of drugs. To increase the intraperitoneal retention time of specific drugs, a pH-sensitive supramolecular hydrogel that can act as a drug delivery vehicle is developed. To establish the optimal formulation of the hydrogel and to study its feasibility, safety, and tissue compatibility, in vitro, postmortem, and in vivo experiments are performed. In vitro tests reveal that a hydrogelator formulation with pH ≥ 9 results in a constant viscosity of 0.1 Pa·s. After administration postmortem, the hydrogel covers the parietal and visceral peritoneum with a thin, soft layer. In the subsequent in vivo experiments, 14 healthy rats are subjected to intraperitoneal injection with the hydrogel. Fourteen and 28 days after implantation, the animals are euthanized. Intraperitoneal exposure to the hydrogel is not resulted in significant weight loss or discomfort. Moreover, no macroscopic adverse effects or signs of organ damage are detected. In several intra-abdominal tissues, vacuolated macrophages are found indicating a physiological degradation of the synthetic hydrogel. This study demonstrates that the supramolecular hydrogel is safe for intraperitoneal application and that the hydrogel shows good tissue compatibility in rats.

Pharmacokinetic evaluation of poorly soluble compounds formulated as nano- or microcrystals after intraperitoneal injection to mice

Intraperitonial (i.p.) delivery during initial stages of drug discovery can allow efficacy readouts for compounds which have suboptimal pharmacokinetics (PK) due to poor physiochemical properties and/or oral bioavailability. A major limitation for widespread use of i.p. administration is the paucity of published data and unclear mechanisms of absorption, particularly when using complex formulations. The aim of the present study was to investigate the PK of poorly soluble compounds with low oral bioavailability when administered i.p. as crystalline nano- and microsuspensions. Three compounds, with varying aqueous solubility (2, 7, and 38 µM, at 37 °C), were dosed to mice at 10 and 50 mg/kg. In vitro dissolution confirmed that nanocrystals dissolved faster than microcrystals and hence were expected to result in higher exposure after i.p. dosing. Surprisingly, the increase in dissolution rate with decrease in particle size did not result in higher in vivo exposure. In contrast, the microcrystals showed higher exposure. The potential of smaller particles to promote access to the lymphatic system is hypothesized and discussed as one plausible explanation. The present work demonstrates the importance of understanding physicochemical properties of drug formulations in the context of the microphysiology at the delivery site and how that knowledge can be leveraged to alter systemic PK.

Focus on the Lymphatic Route to Optimize Drug Delivery in Cardiovascular Medicine

While oral agents have been the gold standard for cardiovascular disease therapy, the new generation of treatments is switching to other administration options that offer reduced dosing frequency and more efficacy. The lymphatic network is a unidirectional and low-pressure vascular system that is responsible for the absorption of interstitial fluids, molecules, and cells from the peripheral tissue, including the skin and the intestines. Targeting the lymphatic route for drug delivery employing traditional or new technologies and drug formulations is exponentially gaining attention in the quest to avoid the hepatic first-pass effect. The present review will give an overview of the current knowledge on the involvement of the lymphatic vessels in drug delivery in the context of cardiovascular disease.

Therapeutic efficacy of a paclitaxel-loaded nanofibrillated bacterial cellulose (PTX/NFBC) formulation in a peritoneally disseminated gastric cancer xenograft model

Nano-fibrillated bacterial cellulose (NFBC) is a safe, biocompatible material that can be prepared by culturing a cellulose-producing bacterium in a culture supplemented with carboxymethylcellulose (CMC) or hydroxypropylcellulose (HPC). CM-NFBC and HP-NFBC, prepared using CMC or HPC, show hydrophilicity and amphiphilicity, respectively, and thus they could be useful carriers for hydrophobic anticancer agents such as paclitaxel (PTX). In the present study, we prepared novel PTX formulations for intraperitoneal administration by associating PTX with either CM-NFBC or HP-NFBC and studied their therapeutic efficacy on peritoneally disseminated gastric cancer in a xenograft nude mouse model. Freeze-dried PTX formulations (PTX/CM-NFBC and PTX/HP-NFBC) were quickly reconstituted with saline without any foaming, compared to nanoparticle albumin-bound PTX (nab-PTX, Abraxane®). Both PTX/NFBC formulations extended the mean survival times in our xenograft murine models compared with either free PTX or nab-PTX. The PTX/NFBC formulations reduced systemic side effects of free PTX relating to weight loss. In our disseminated gastric peritoneal cancer model, the PTX/NFBC formulation increased the therapeutic index for PTX by increasing the therapeutic efficacy and decreasing toxicity. NFBCs should receive consideration as improved carriers for the clinical delivery of hydrophobic anticancer drugs such as PTX in malignancies in the abdominal cavity with peritoneal metastasis and dissemination.

Lymph-directed immunotherapy - Harnessing endogenous lymphatic distribution pathways for enhanced therapeutic outcomes in cancer

The advent of immunotherapy has revolutionised the treatment of some cancers. Harnessing the immune system to improve tumour cell killing is now standard clinical practice and immunotherapy is the first line of defence for many cancers that historically, were difficult to treat. A unifying concept in cancer immunotherapy is the activation of the immune system to mount an attack on malignant cells, allowing the body to recognise, and in some cases, eliminate cancer. However, in spite of a significant proportion of patients that respond well to treatment, there remains a subset who are non-responders and a number of cancers that cannot be treated with these therapies. These limitations highlight the need for targeted delivery of immunomodulators to both tumours and the effector cells of the immune system, the latter being highly concentrated in the lymphatic system. In this context, macromolecular therapies may provide a significant advantage. Macromolecules are too large to easily access blood capillaries and instead typically exhibit preferential uptake via the lymphatic system. In contexts where immune cells are the therapeutic target, particularly in cancer therapy, this may be advantageous. In this review, we examine in brief the current immunotherapy approaches in cancer and how macromolecular and nanomedicine strategies may improve the therapeutic profiles of these drugs. We subsequently discuss how therapeutics directed either by parenteral or mucosal administration, can be taken up by the lymphatics thereby accessing a larger proportion of the body's immune cells. Finally, we detail drug delivery strategies that have been successfully employed to target the lymphatics.

Pharmacokinetic and Pharmacodynamic Evaluation of Resveratrol Loaded Cationic Liposomes for Targeting Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. The destructive nature of the disease makes it difficult for clinicians to manage the condition. Hence, there is an urgent need to find new alternatives for HCC, as the role of conventional cytotoxic drugs has reached a plateau to control HCC associated mortality. Antioxidant compounds of plant origin with potential anti-tumor effect have been recognized as alternate modes in cancer treatment and chemoprevention. Resveratrol (RS) is a model natural nonflavonoid drug known for its anti-cancer activity. However, its clinical application is limited due to its poor bioavailability. The current research work aims to formulate, optimize, and characterize RS loaded cationic liposomes (RLs) for specific delivery in HCC. The optimized liposomes formulation (RL5) was spherical with a vesicle size (VS) of 145.78 ± 9.9 nm, ζ potential (ZP) of 38.03 ± 9.12 mV, and encapsulation efficiency (EE) of 78.14 ± 8.04%. In vitro cytotoxicity studies in HepG2 cells demonstrated an improved anti-cancer activity of RL5 in comparison with free RS. These outcomes were supported by a cell uptake study in HepG2 cells, in which RL5 exhibited a higher uptake than free RS. Furthermore, confocal images of HepG2 cells after 3 and 5 h of incubation showed higher internalization of coumarin 6 (C6) loaded liposomes (CL) as compared to those of the free C6. Pharmacokinetic and pharmacodynamic (prophylactic and therapeutic treatment modalities) studies were performed in N-nitrosodiethylamine (NDEA-carcinogen) induced HCC in rats. Pharmacokinetic evaluation of RL5 demonstrated increased localization of RS in cancerous liver tissues by 3.2- and 2.2-fold increase in AUC and Cmax, respectively, when compared to those of the free RS group. A pharmacodynamic investigation revealed a significant reduction in hepatocyte nodules in RL5 treated animals when compared to those of free RS. Further, on treatment with RL5, HCC-bearing rats showed a significant decrease in the liver marker enzymes (alanine transaminase, alkaline phosphatase, aspartate transaminase, total bilirubin levels, γ-glutamyl transpeptidase, and α-fetoprotein), in comparison with that of the disease control group. Our findings were supported by histopathological analysis, and we were first to demonstrate that NDEA induced detrimental effect on rat livers was successfully reversed with the treatment of RL5 formulation. These results implied that delivery of RS loaded cationic liposomes substantially controlled the severity of HCC and that they can be considered as a promising nanocarrier in the management of HCC.

Stromal Modulation and Treatment of Metastatic Pancreatic Cancer with Local Intraperitoneal Triple miRNA/siRNA Nanotherapy

Nanomedicines achieve tumor-targeted delivery mainly through enhanced permeability and retention (EPR) effect following intravenous (IV) administration. Unfortunately, the EPR effect is severely compromised in pancreatic cancer due to hypovascularity and dense desmoplastic stroma. Intraperitoneal (IP) administration may be an effective EPR-independent local delivery approach to target peritoneal tumors. Besides improved delivery, effective combination delivery strategies are needed to improve pancreatic cancer therapy by targeting both cancer cells and cellular interactions within the tumor stroma. Here, we described simple cholesterol-modified polymeric CXCR4 antagonist (PCX) nanoparticles (to block cancer-stroma interactions) for codelivery of anti-miR-210 (to inactivate stroma-producing pancreatic stellate cells (PSCs)) and siKRASG12D (to kill pancreatic cancer cells). IP administration delivered the nanoparticles to an orthotopic syngeneic pancreatic tumors as a result of preferential localization to the tumors and metastases with disrupted mesothelium and effective tumor penetration. The local IP delivery resulted in nearly 15-fold higher tumor accumulation than delivery by IV injection. Through antagonism of CXCR4 and downregulation of miR-210/KRASG12D, the triple-action nanoparticles favorably modulated desmoplastic tumor microenvironment via inactivating PSCs and promoting the infiltration of cytotoxic T cells. The combined therapy displayed improved therapeutic effect when compared with individual therapies as documented by the delayed tumor growth, depletion of stroma, reduction of immunosuppression, inhibition of metastasis, and prolonged survival. Overall, we present data that a local IP delivery of a miRNA/siRNA combination holds the potential to improve pancreatic cancer therapy.

Release of doxorubicin from its liposomal coating via high intensity ultrasound

The present ex vivo study was performed to analyze the impact of high intensity ultrasound (HIUS) on penetration depth and particle stability of liposomal doxorubicin (LD) on the peritoneal surface. Fresh post mortem swine peritoneum was cut into proportional sections and subjected to a previously established ex vivo model of pressurized intraperitoneal aerosol chemotherapy (PIPAC). Samples were treated with 50 ml NaCl (0.9%) containing 3 mg LD via PIPAC or lavage. In both groups, half of the samples received additional HIUS treatment. Samples treated via PIPAC were covered with a 30-mm-thick abdominal muscle wall tissue, fatty tissue and skin, followed by transcutaneous HIUS. Samples administered with LD via lavage received close-range contact HIUS. Doxorubicin tissue penetration was measured using fluorescence microscopy on frozen sections. Liposomal integrity on peritoneal surfaces was measured via electron microscopy (EM). Mean penetration rates of doxorubicin were significantly higher with HIUS in combination with PIPAC or lavage compared with PIPAC alone (P<0.001) or lavage alone (P<0.00001). LD was not detected on the peritoneal surface via EM analysis in either group following HIUS. The present data suggested that HIUS may be a feasible application that can facilitate the release of doxorubicin from its liposomal envelope. HIUS was effective in both close-range, in contact with the samples, and through the abdominal wall. The present approach may be used in the future for both endoscopic and open lavage of the peritoneal cavity with LD in intraperitoneal chemotherapeutic applications such as hyperthermic intraperitoneal chemotherapy or PIPAC.

Aerosolization of Nanotherapeutics as a Newly Emerging Treatment Regimen for Peritoneal Carcinomatosis

Recent advances in locoregional chemotherapy have opened the door to new approaches for the clinical management of peritoneal carcinomatosis (PC) by facilitating the delivery of anti-neoplastic agents directly to the tumor site, while mitigating adverse effects typically associated with systemic administration. In particular, an innovative intra-abdominal chemotherapeutic approach, known as Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC), was recently introduced to the intraperitoneal (IP) therapy regimens as a palliative therapeutic option in patients with PC, presumably providing a better drug distribution pattern together with deeper drug penetration into tumor nodules within the peritoneal space. Furthermore, the progress of nanotechnology in the past few decades has prompted the application of different nanomaterials in IP cancer therapy, offering new possibilities in this field ranging from an extended retention time to sustained drug release in the peritoneal cavity. This review highlights the progress, challenges, and opportunities in utilizing cancer nanotherapeutics for locoregional drug delivery, with a special emphasis on the aerosolization approach for intraperitoneal therapies.

Therapeutic delivery to the peritoneal lymphatics: Current understanding, potential treatment benefits and future prospects

The interest in approaches to deliver therapeutics to the lymphatic system has increased in recent years as the lymphatics have been discovered to play an important role in a range of disease states such as cancer metastases, inflammatory and metabolic disease, and acute and critical illness. Therapeutic delivery to lymph has the potential to enhance treatment of these conditions. Currently much of the existing data explores therapeutic delivery to the lymphatic vessels and nodes that drain peripheral tissues and the intestine. Relatively little focus has been given to understanding the anatomy, function and therapeutic delivery to the peritoneal lymphatics. Gaining a better understanding of peritoneal lymphatic structure and function would contribute to the understanding of disease processes involving these lymphatics and facilitate the development of delivery systems to target therapeutics to the peritoneal lymphatics. This review explores the basic anatomy and ultrastructure of the peritoneal lymphatics system, the lymphatic drainage pathways from the peritoneum, and therapeutic and delivery system characteristics (size, lipophilicity and surface properties) that favour lymph uptake and retention after intraperitoneal delivery. Finally, techniques that can be used to quantify uptake into peritoneal lymph are outlined, providing a platform for future studies.

Nanoformulation of Talazoparib Delays Tumor Progression and Ascites Formation in a Late Stage Cancer Model

Talazoparib, a potent PARP inhibitor, induces synthetic lethality in BRCA-deficient cancers making it an attractive candidate for ovarian cancer treatment. However, its potency lends itself to side effects associated more closely with traditional chemotherapeutics than other clinically approved PARP inhbitors. We sought to formulate Talazoparib in a nanoparticle delivery system, which allows the drug to be administered intraperitoneally. This was done to specifically target peritoneal dissemination of late stage metastatic ovarian cancer and increase talazoparib's therapeutic efficacy while minimizing toxic side effects. NanoTalazoparib was developed and characterized with regard to its size, loading, and surface charge. Talazoparib and NanoTalazoparib were tested on a panel of murine and human BRCA cell lines and the dose response was compared to Olaparib's, the currently used PARP inhibitor. Therapeutic efficacy was tested in vivo in a Brca peritoneal cancer model that mimics late stage disseminated disease. NanoTalazoparib has a diameter of about 70 nm with a neutral surface charge and ~75% encapsulation efficiency, which slowly releases the drug over several hours. Dose response analysis indicated that the murine cell lines with conditional BRCA1/2, PTEN, and TP53 deletions had the lowest IC50s. NanoTalazoparib administered on a schedule of three doses weekly slowed disease progression and resulted in significantly less mice with ascites at the end point compared to controls. These results indicate that the slow release nanoformulation, NanoTalazoparib, effectively delivers PARP inhibitor therapy to the peritoneal cavity for disseminated cancer treatment. The ability to decrease ascites formation with the introduction of intraperitoneal NanoTalazoparib suggests this treatment may be an effective way to treat ovarian cancer-associated ascites and slow disease progression.

Abrogation of Endogenous Glycolipid Antigen Presentation on Myelin-Laden Macrophages by D-Sphingosine Ameliorates the Pathogenesis of Experimental Autoimmune Encephalomyelitis

Background: Although myelin is composed of mostly lipids, the pathological role of myelin lipids in demyelinating diseases remains elusive. The principal lipid of the myelin sheath is β-galactosylceramide (β-Galcer). Its α-anomer (α-Galcer) has been demonstrated to be antigenically presented by macrophages via CD1d, a MHC class I-like molecule. Myelin, which is mostly composed of β-Galcer, has been long considered as an immunologically-inert neuron insulator, because the antigen-binding cleft of CD1d is highly α-form-restricted.

Results: Here, we report that CD1d-mediated antigenic presentation of myelin-derived galactosylceramide (Mye-GalCer) by macrophages contributed significantly to the progression of experimental autoimmune encephalomyelitis (EAE). Surprisingly, this presentation was recognizable by α-Galcer:CD1d-specific antibody (clone L363), but incapable of triggering expansion of iNKT cells and production of iNKT signature cytokines (IFNγ and IL-4). Likewise, a synthesized analog of Mye-Galcer, fluorinated α-C-GalCer (AA2), while being efficiently presented via CD1d on macrophages, failed to stimulate production of IFNγ and IL-4. However, AA2 significantly exacerbated EAE progression. Further analyses revealed that the antigenic presentations of both Mye-GalCer and its analog (AA2) in α-form via CD1d promoted IL-17 production from T cells, leading to elevated levels of IL-17 in EAE spinal cords and sera. The IL-17 neutralizing antibody significantly reduced the severity of EAE symptoms in AA2-treated mice. Furthermore, D-sphingosine, a lipid possessing the same hydrophobic base as ceramide but without a carbohydrate residue, efficiently blocked this glycolipid antigen presentation both in vitro and in spinal cords of EAE mice, and significantly decreased IL-17 and ameliorated the pathological symptoms.

Conclusion: Our findings reveal a novel pathway from the presentation of Mye-GalCer to IL-17 production, and highlight the promising therapeutic potential of D-sphingosine for the human disorder of multiple sclerosis.

Evaluation of the Biological Behavior of a Gold Nanocore-Encapsulated Human Serum Albumin Nanoparticle (Au@HSANP) in a CT-26 Tumor/Ascites Mouse Model after Intravenous/Intraperitoneal Administration

Colorectal cancer is one of the major causes of cancer-related death in Taiwan and worldwide. Patients with peritoneal metastasis from colorectal cancer have reduced overall survival and poor prognosis. Hybrid protein-inorganic nanoparticle systems have displayed multifunctional applications in solid cancer theranostics. In this study, a gold nanocore-encapsulated human serum albumin nanoparticle (Au@HSANP), which is a hybrid protein-inorganic nanoparticle, and its radioactive surrogate ¹¹¹In-labeled Au@HSANP (¹¹¹In-Au@HSANP), were developed and their biological behaviors were investigated in a tumor/ascites mouse model. ¹¹¹In-Au@HSANP was injected either intravenously (iv) or intraperitoneally (ip) in CT-26 tumor/ascites-bearing mice. After ip injection, a remarkable and sustained radioactivity retention in the abdomen was noticed, based on microSPECT images. After iv injection, however, most of the radioactivity was accumulated in the mononuclear phagocyte system. The results of biodistribution indicated that ip administration was significantly more effective in increasing intraperitoneal concentration and tumor accumulation than iv administration. The ratios of area under the curve (AUC) of the ascites and tumors in the ip-injected group to those in the iv-injected group was 93 and 20, respectively. This study demonstrated that the ip injection route would be a better approach than iv injections for applying gold-albumin nanoparticle in peritoneal metastasis treatment.

Establishing the effects of mesoporous silica nanoparticle properties on in vivo disposition using imaging-based pharmacokinetics

The progress of nanoparticle (NP)-based drug delivery has been hindered by an inability to establish structure-activity relationships in vivo. Here, using stable, monosized, radiolabeled, mesoporous silica nanoparticles (MSNs), we apply an integrated SPECT/CT imaging and mathematical modeling approach to understand the combined effects of MSN size, surface chemistry and routes of administration on biodistribution and clearance kinetics in healthy rats. We show that increased particle size from ~32- to ~142-nm results in a monotonic decrease in systemic bioavailability, irrespective of route of administration, with corresponding accumulation in liver and spleen. Cationic MSNs with surface exposed amines (PEI) have reduced circulation, compared to MSNs of identical size and charge but with shielded amines (QA), due to rapid sequestration into liver and spleen. However, QA show greater total excretion than PEI and their size-matched neutral counterparts (TMS). Overall, we provide important predictive functional correlations to support the rational design of nanomedicines.

Nanoparticle applications are limited by insufficient understanding of physiochemical properties on in vivo disposition. Here, the authors explore the influence of size, surface chemistry and administration on the biodisposition of mesoporous silica nanoparticles using image-based pharmacokinetics.

Effect of Liposomal Doxorubicin in Pressurized Intra-Peritoneal Aerosol Chemotherapy (PIPAC)

Background: This ex-vivo study was performed to compare the impact of doxorubicin vs. liposomal doxorubicin on penetration depth in peritoneal tissue during Pressurized Intra-Peritoneal Aerosol Chemotherapy (PIPAC) via microcatheter (MC). Methods: Fresh post mortem swine peritoneum was cut into proportional sections. One group of samples was treated with PIPAC with Doxorubicin (D), and the other was treated with PIPAC with liposomal doxorubicin (LD). Tissue specimens were placed as follows: at the bottom of the plastic box (1), at the side wall (2), at the top cover (3) and the side of the box covered by a plastic tunnel (4). In-tissue doxorubicin penetration was measured using fluorescence microscopy on frozen thin sections. Results: Medium penetration levels with D were 325 µm (1), 152 µm (2), 84 µm (3) and 71 µm (4), respectively. Medium penetration levels with LD were significantly lower with 10 µm (1), 2 µm (2), 0 µm (3) and 0 µm (4), respectively. In most samples that were treated with LD no doxorubicin could be detected at all. Conclusion: Our data indicate that liposomal coating of doxorubicin and possibly other chemotherapeutical drugs might inhibit their interaction with the peritoneal surface. This inhibition appears to be relatively strong, since doxorubicin is partially undetectable due to liposomal coating. Further studies are warranted to investigate this interaction and its potential benefit in peritoneal applications.

Peritoneal Carcinomatosis Targeting with Tumor Homing Peptides

Over recent decades multiple therapeutic approaches have been explored for improved management of peritoneally disseminated malignancies—a grim condition known as peritoneal carcinomatosis (PC). Intraperitoneal (IP) administration can be used to achieve elevated local concentration and extended half-life of the drugs in the peritoneal cavity to improve their anticancer efficacy. However, IP-administered chemotherapeutics have a short residence time in the IP space, and are not tumor selective. An increasing body of work suggests that functionalization of drugs and nanoparticles with targeting peptides increases their peritoneal retention and provides a robust and specific tumor binding and penetration that translates into improved therapeutic response. Here we review the progress in affinity targeting of intraperitoneal anticancer compounds, imaging agents and nanoparticles with tumor-homing peptides. We review classes of tumor-homing peptides relevant for PC targeting, payloads for peptide-guided precision delivery, applications for targeted compounds, and the effects of nanoformulation of drugs and imaging agents on affinity-based tumor delivery.

Improvement of anti-cancer drug efficacy via thermosensitive hydrogel in peritoneal carcinomatosis in gastric cancer

Peritoneal carcinomatosis (PC) of gastric origin has a poor prognosis with short survival due to lack of effective therapeutic modalities. Here, we evaluated the therapeutic efficacy of an injectable thermosensitive poly (organophosphazene) (PPZ) hydrogel with docetaxel (DTX-gel) to develop an effective therapeutic agent for patient with PC. Three days after inoculation of highly metastatic 44As3Luc cells into peritoneal cavity, the mice were intravenously or intraperitoneally administered with docetaxel alone (DTX-sol IV or IP), and intraperitoneally injected with DTX-gel. The anti-tumor activity was monitored by bioluminescence live imaging system. Compared to DTX-sol IV or IP, the tumor growth was significantly reduced in the DTX-gel treated mice (p<0.0001, p=0.0001). Furthermore, the survival rate was significantly increased in the DTX-gel treated mice compared to DTX-sol IV or IP treated mice (p<0.0001, p=0.0068). Our results demonstrated that DTX-gel suppresses peritoneal metastasis by continuing release of chemotherapy agent, which leads to increase the survival rate in a PC model. Therefore, biodegradable thermosensitive hydrogel with docetaxel system can be a good anti-cancer agent for PC.

Tumor Penetrating Theranostic Nanoparticles for Enhancement of Targeted and Image-guided Drug Delivery into Peritoneal Tumors following Intraperitoneal Delivery

The major obstacles in intraperitoneal (i.p.) chemotherapy of peritoneal tumors are fast absorption of drugs into the blood circulation, local and systemic toxicities, inadequate drug penetration into large tumors, and drug resistance. Targeted theranostic nanoparticles offer an opportunity to enhance the efficacy of i.p. therapy by increasing intratumoral drug delivery to overcome resistance, mediating image-guided drug delivery, and reducing systemic toxicity. Herein we report that i.p. delivery of urokinase plasminogen activator receptor (uPAR) targeted magnetic iron oxide nanoparticles (IONPs) led to intratumoral accumulation of 17% of total injected nanoparticles in an orthotopic mouse pancreatic cancer model, which was three-fold higher compared with intravenous delivery. Targeted delivery of near infrared dye labeled IONPs into orthotopic tumors could be detected by non-invasive optical and magnetic resonance imaging. Histological analysis revealed that a high level of uPAR targeted, PEGylated IONPs efficiently penetrated into both the peripheral and central tumor areas in the primary tumor as well as peritoneal metastatic tumor. Improved theranostic IONP delivery into the tumor center was not mediated by nonspecific macrophage uptake and was independent from tumor blood vessel locations. Importantly, i.p. delivery of uPAR targeted theranostic IONPs carrying chemotherapeutics, cisplatin or doxorubicin, significantly inhibited the growth of pancreatic tumors without apparent systemic toxicity. The levels of proliferating tumor cells and tumor vessels in tumors treated with the above theranostic IONPs were also markedly decreased. The detection of strong optical signals in residual tumors following i.p. therapy suggested the feasibility of image-guided surgery to remove drug-resistant tumors. Therefore, our results support the translational development of i.p. delivery of uPAR-targeted theranostic IONPs for image-guided treatment of peritoneal tumors.

Nanomedicine-based intraperitoneal therapy for the treatment of peritoneal carcinomatosis - Mission possible?

Intraperitoneal (IP) drug delivery represents an attractive strategy for the local treatment of peritoneal carcinomatosis (PC). Over the past decade, a lot of effort has been put both in the academia and clinic in developing IP therapeutic approaches that maximize local efficacy while limiting systemic side effects. Also nanomedicines are under investigation for the treatment of tumors confined to the peritoneal cavity, due to their potential to increase the peritoneal retention and to target drugs to the tumor sites as compared to free drugs. Despite the progress reported by multiple clinical studies, there are no FDA approved drugs or formulations for specific use in the IP cavity yet. This review discusses the current clinical management of PC, as well as recent advances in nanomedicine-based IP delivery. We address important challenges to be overcome towards designing optimal nanocarriers for IP therapy in vivo.

Ultrasound-mediated destruction of oxygen and paclitaxel loaded dual-targeting microbubbles for intraperitoneal treatment of ovarian cancer xenografts

Folate receptor (FR) is overexpressed in many epithelial cancers and tumor-associated macrophages (TAMs), which enable it to function as an appropriate target for cancer treatment. We have successfully synthesized multifunctional folate-targeted and oxygen/paclitaxel loaded microbubbles (TOPLMBs) for ultrasound (US) mediated delivery for combination therapy in an intraperitoneal ovarian cancer xenograft model. The TOPLMBs target both ovarian cancer cells and TAMs and provide a promising drug delivery strategy for the combination treatment of ovarian cancer and tumor microenvironment. Microscopic imaging and flow cytometric analysis showed that TOPLMBs significantly penetrated into ovarian cancer cells and tumor-associated macrophages (TAMs) within tumor ascites fluid and the tumor nodules. Immunohistochemical analyses of dissected tumor tissue confirmed the increased tumor apoptosis, the reduced expression of vascular endothelial growth factor (VEGF) and microvascular density (MVD), and the reduced expression of CD68 after treatment (P < 0.05). Our experiment results suggest that intraperitoneal injection of dual-targeting TOPLMBs followed by US mediation provide a promising drug delivery strategy for combination treatment of ovarian cancer and tumor microenvironment with the therapeutic outcome superior to that of conventional therapeutic options.

Lung-targeting drug delivery system of baicalin-loaded nanoliposomes: development, biodistribution in rabbits, and pharmacodynamics in nude mice bearing orthotopic human lung cancer

The present study aims to develop a kind of novel nanoliposomes for the lung-targeting delivery system of baicalin as a Chinese medicine monomer. Baicalin-loaded nanoliposomes were prepared by the effervescent dispersion and lyophilized techniques. Baicalin-loaded nanoliposomes had an average particle size of 131.7±11.7 nm with 0.19±0.02 polydispersity index, 82.8%±1.24% entrapment efficiency and 90.47%±0.93% of yield and sustaining drug release effect over 24 h and were stable for 12 months at least. In vitro no hemolytic activity was observed for the experimental drug concentration. After intravenous administration of baicalin-loaded nanoliposomes to rabbits, drug concentration in the lungs was the highest among the tested organs at all time points and was significantly higher than that of its solution. For the targeting parameters, the relative intake rate and the ratio of peak concentration of lung were 4.837 and 2.789, respectively. Compared with plasma, liver, spleen, and kidney, the ratios of targeting efficacy (T_e)_liposomes to (T_e)_injection of lung were increased by a factor of 14.131, 1.893, 3.357, and 3.470, respectively. Furthermore, the results showed that the baicalin-loaded nanoliposomes did not induce lung injury. Importantly, baicalin-loaded nanoliposomes showed better antitumor therapeutic efficacy in the nude mice bearing orthotopic human lung cancer with the median survival time of blank liposomes (11.40±0.16 days), baicalin solution (17.30±0.47 days), and baicalin-loaded nanoliposomes (25.90±0.53 days). Therefore, the liposome is a promising drug carrier with an excellent lung-targeting property and therapeutic effect for the treatment of lung disease, such as lung cancer.

Pharmacokinetic problems in peritoneal drug administration: an update after 20 years

Intraperitoneal chemotherapy has demonstrated significant pharmacologic and clinical advantage over traditional intravenous administration for cancers that are restricted to the peritoneal cavity. The combination of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) has become the standard technique used to fight ovarian and gastrointestinal cancers in many centers. However, challenges remain for HIPEC to contact the entire peritoneal surface, penetrate the tumor tissue, and transport to the lymphatics and other metastatic sites. New innovations in delivery technique, such as heated aerosol, and in delivery molecules, such as microparticles, nanoparticles, nanogels, and tumor-penetrating peptides are being tested in animal models and will likely soon be in human trials. Improvements in overall care, such as the recent clinical trial of an oral agent for maintenance therapy in ovarian carcinoma, will continue in this field for the next 20 years.

Thermosensitive hydrogel system assembled by PTX-loaded copolymer nanoparticles for sustained intraperitoneal chemotherapy of peritoneal carcinomatosis

Intraperitoneal (IP) chemotherapy is a preferable treatment option for peritoneal carcinomatosis of malignancies by delivering chemotherapeutic drugs into the abdominal cavity. A persistent major challenge in IP chemotherapy is the need to provide effective drug concentration in the peritoneal cavity for an extended period of time. In the present work, the thermosensitive hydrogel system (PTX/PECT(gel)) assembled by PTX (paclitaxel)-loaded amphiphilic copolymer (PECT, poly (ε-caprolactone-co-1,4,8-trioxa [4.6]spiro-9-undecanone)-poly(ethylene glycol)-poly (ε-caprolactone-co-1,4,8-trioxa [4.6]spiro-9-undecanone)) nanoparticles was developed for sustained IP chemotherapy of peritoneal carcinomatosis model. Cytotoxicity assay indicated that PECT hydrogel was biocompatible with very low cytotoxicity and PTX/PECT(gel) had enhanced cytotoxicity than free PTX. In vivo toxicity study demonstrated the biocompatibility and biosafety of PECT hydrogel as an IP chemotherapy carrier. The fluorescence imaging method was employed to monitor the intraperitoneal degradation of PECT hydrogel by labeling PECT with rhodamine B. PECT hydrogel with the dose of 200μL showed about 8days' retention time and most of the injected hydrogel was located in the intestine. The anti-tumor efficacy study was carried out in mice bearing CT26 intraperitoneal ascites fluid as colorectal peritoneal carcinomatosis model. The result showed that intraperitoneal administration of PTX/PECT(gel) could effectively suppress growth and metastasis of CT26 peritoneal carcinomatosis in vivo, compared with Taxol® group. The pharmacokinetic studies demonstrated that PTX/PECT(gel) could improve the bioavailability of PTX by being formulated in PECT hydrogel. Overall, sustained drug concentration at peritoneal levels in combination with drug in the form of nanoparticle contributes to the enhanced anti-tumor efficacy. Thus, our results suggested that PTX/PECT(gel) may have great potential applications in IP chemotherapy.

Improving paclitaxel pharmacokinetics by using tumor-specific mesoporous silica nanoparticles with intraperitoneal delivery

Mesoporous silica nanoparticles (MSNs) containing paclitaxel for intraperitoneal (i.p.) delivery were developed to exploit the tumor specific accumulation of these nanocarriers after i.p. injection and the slow release of paclitaxel from the MSNs. A 3.5-fold increase in tumor cellular drug uptake was observed for the paclitaxel-loaded MSNs compared with free paclitaxel. An in vivo study using xenograft mice bearing peritoneal human pancreatic carcinoma MIA PaCa-2 demonstrated that the MSN-paclitaxel formulation, compared to free paclitaxel, exhibited a 3.2-fold increase in peritoneal cavity residence time, slower absorption into the systemic circulation with one third systemic exposure, but a 6.5-fold increase in peritoneal tumor accumulation. Tissue distribution imaging showed significantly greater accumulation of fluorescent MSNs in tumor tissues compared to other peritoneal tissues. In conclusion, intraperitoneal administration of drug-containing MSNs was effective at reducing systemic exposure and increasing the peritoneal tumor accumulation of paclitaxel.

Versatility of Particulate Carriers: Development of Pharmacodynamically Optimized Drug-Loaded Microparticles for Treatment of Peritoneal Cancer

Intraperitoneal (IP) chemotherapy confers significant survival benefits in cancer patients. However, several problems, including local toxicity and ineffectiveness against bulky tumors, have prohibited it from becoming a standard-of-care. We have developed drug-loaded, tumor-penetrating microparticles (TPM) to address these problems. TPM comprises two components and uses the versatile PLGA or poly(lacticco-glycolic acid) copolymer to provide tumor-selective adherence and pharmacodynamically optimized fractionated dosing to achieve the desired tumor priming (which promotes particle penetration into tumors) plus immediate and sustained antitumor activity. Preclinical studies show that TPM is less toxic and more effective against several IP metastatic tumors with different characteristics (fast vs. slow growing, porous vs. densely packed structures, wide-spread vs. solitary tumors, early vs. late stage, with or without peritoneal carcinomatosis or ascites), compared to the intravenous paclitaxel/Cremophor micellar solution that has been used off-label in previous IP studies. TPM further requires less frequent dosing. These encouraging preclinical results have motivated the follow-up clinical development of TPM. We are working with National Institutes of Health on the IND-enabling studies.

Synergistic effects of co-administration of suicide gene expressing mesenchymal stem cells and prodrug-encapsulated liposome on aggressive lung melanoma metastases in mice

The success of conventional suicide gene therapy for cancer treatment is still limited because of lack of efficient delivery methods, as well as poor penetration into tumor tissues. Mesenchymal stem cells (MSCs) have recently emerged as potential vehicles in improving delivery issues. However, these stem cells are usually genetically modified using viral gene vectors for suicide gene overexpression to induce sufficient therapeutic efficacy. This approach may result in safety risks for clinical translation. Therefore, we designed a novel strategy that uses non-viral gene vector in modifying MSCs with suicide genes to reduce risks. In addition, these cells were co-administrated with prodrug-encapsulated liposomes for synergistic anti-tumor effects. Results demonstrate that this strategy is effective for gene and prodrug delivery, which co-target tumor tissues, to achieve a significant decrease in tumor colonization and a subsequent increase in survival in a murine melanoma lung metastasis model. Moreover, for the first time, we demonstrated the permeability of MSCs within tumor nests by using an in vitro 3D tumor spheroid model. Thus, the present study provides a new strategy to improve the delivery problem in conventional suicide gene therapy and enhance the therapeutic efficacy. Furthermore, this study also presents new findings to improve our understanding of MSCs in tumor-targeted gene delivery.

Albumin nanoparticles increase the anticancer efficacy of albendazole in ovarian cancer xenograft model

Background

The poor prognosis of patients with drug resistant ovarian cancer and the lack of targeted therapy have raised the need for alternative treatments. Albendazole (ABZ) is an anti-parasite compound capable of impairing microtubule formation. We hypothesized that ABZ could be repurposed as a potential anti-angiogenic drug due to its potent inhibition of vascular endothelial growth factor (VEGF) in ovarian cancer with ascites. However, the poor aqueous solubility of ABZ limits its potential for cancer therapy. In this study, we have assembled ABZ with bovine serum albumin into nanoparticles with a size range of 7–10 nm (BSA-ABZ) and 200–250 nm (Nab-ABZ). We further examined the anticancer effects of ABZ carrying nanoparticles in ovarian cancer cells, in both in vitro and in vivo models.

Results

Drug release studies demonstrated that about 93% of ABZ was released from BSA-ABZ 10 nm in comparison to 83% from Nab-ABZ 200 nm at pH 7.4 in 8 days. In vitro cell proliferation studies showed that the BSA-ABZ 10 nm exhibited the highest killing efficacy of ovarian cancer cells with surprisingly least toxicity to healthy ovarian epithelial cells. Confocal microscopy and fluorescence activated cell sorting analysis (FACS) revealed more efficient internalization of the BSA-ABZ 10 nm by cancer cells. For in vivo studies, we examined the tumor growth, ascites formation and the expression of VEGF and secreted protein acidic and rich in cysteine (SPARC) in tumor samples and only VEGF in plasma samples. The BSA-ABZ 10 nm reduced the tumor burden significantly (p < 0.02) at a much lower drug dose (10 μg/ml) compare to free drug. Both formulations were capable of suppressing the ascites volume significantly (p < 0.05) and reducing the number of ascites cells. The expression of VEGF and SPARC was also reduced, which indicates the underlying therapeutic mechanism of the ABZ.

Conclusion

Our data suggest that the BSA-ABZ may hold promise for the treatment and control of progression of ovarian cancer with ascites. However further studies are required to examine the efficacy of both the formulations in aggressive models of recurrent ovarian cancer with respect to particle size and dosing parameters.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-015-0082-8) contains supplementary material, which is available to authorized users.

Intraperitoneal delivery of platinum with in-situ crosslinkable hyaluronic acid gel for local therapy of ovarian cancer

Intraperitoneal (IP) chemotherapy is a promising post-surgical therapy of solid carcinomas confined within the peritoneal cavity, with potential benefits in locoregional and systemic management of residual tumors. In this study, we intended to increase local retention of platinum in the peritoneal cavity over a prolonged period of time using a nanoparticle form of platinum and an in-situ crosslinkable hyaluronic acid gel. Hyaluronic acid was chosen as a carrier due to the biocompatibility and biodegradability. We confirmed a sustained release of platinum from the nanoparticles (PtNPs) and nanoparticle/gel hybrid (PtNP/gel), receptor-mediated endocytosis of PtNPs, and retention of the gel in the peritoneal cavity over 4 weeks: conditions desirable for a prolonged local delivery of platinum. However, PtNPs and PtNP/gel did not show a greater anti-tumor efficacy than CDDP solution administered at the same dose but rather caused a slight increase in tumor burdens at later time points, which suggests a potential involvement of empty carriers and degradation products in the growth of residual tumors. This study alerts that although several materials considered biocompatible and safe are used as drug carriers, they may have unwanted biological effects on the residual targets once the drug is exhausted; therefore, more attention should be paid to the selection of drug carriers.

Multifunctional, stimuli-sensitive nanoparticulate systems for drug delivery

The use of nanoparticulate pharmaceutical drug delivery systems (NDDSs) to enhance the in vivo effectiveness of drugs is now well established. The development of multifunctional and stimulus-sensitive NDDSs is an active area of current research. Such NDDSs can have long circulation times, target the site of the disease and enhance the intracellular delivery of a drug. This type of NDDS can also respond to local stimuli that are characteristic of the pathological site by, for example, releasing an entrapped drug or shedding a protective coating, thus facilitating the interaction between drug-loaded nanocarriers and target cells or tissues. In addition, imaging contrast moieties can be attached to these carriers to track their real-time biodistribution and accumulation in target cells or tissues. Here, I highlight recent developments with multifunctional and stimuli-sensitive NDDSs and their therapeutic potential for diseases including cancer, cardiovascular diseases and infectious diseases.

Association of liposome-encapsulated trivalent antimonial with ascorbic acid: an effective and safe strategy in the treatment of experimental visceral leishmaniasis

BACKGROUND

Visceral leishmaniasis (VL) is a chronic debilitating disease endemic in tropical and subtropical areas, caused by protozoan parasites of the genus Leishmania. Annually, it is estimated the occurrence of 0.2 to 0.4 million new cases of the disease worldwide. Considering the lack of an effective vaccine the afflicted population must rely on both, an accurate diagnosis and successful treatment to combat the disease. Here we propose to evaluate the efficacy of trivalent antimonial encapsulated in conventional liposomes, in association with ascorbic acid, by monitoring its toxicity and efficacy in BALB/c mice infected with Leishmania infantum.

METHODOLOGY/PRINCIPAL FINDINGS

Infected mice were subjected to single-dose treatments consisting in the administration of either free or liposome-encapsulated trivalent antimony (SbIII), in association or not with ascorbic acid. Parasite burden was assessed in the liver, spleen and bone marrow using the serial limiting dilution technique. After treatment, tissue alterations were examined by histopathology of liver, heart and kidney and confirmed by serum levels of classic biomarkers. The phenotypic profile of splenocytes was also investigated by flow cytometry. Treatment with liposome-encapsulated SbIII significantly reduced the parasite burden in the liver, spleen and bone marrow. Co-administration of ascorbic acid, with either free SbIII or its liposomal form, did not interfere with its leishmanicidal activity and promoted reduced toxicity particularly to the kidney and liver tissues.

CONCLUSIONS/SIGNIFICANCE

Among the evaluated posological regimens treatment of L. infantum-infected mice with liposomal SbIII, in association with ascorbic acid, represented the best alternative as judged by its high leishmanicidal activity and absence of detectable toxic effects. Of particular importance, reduction of parasite burden in the bone marrow attested to the ability of SbIII-carrying liposomes to efficiently reach this body compartment.

Intraperitoneal administration of a tumor-associated antigen SART3, CD40L, and GM-CSF gene-loaded polyplex micelle elicits a vaccine effect in mouse tumor models

Polyplex micelles have demonstrated biocompatibility and achieve efficient gene transfection in vivo. Here, we investigated a polyplex micelle encapsulating genes encoding the tumor-associated antigen squamous cell carcinoma antigen recognized by T cells-3 (SART3), adjuvant CD40L, and granulocyte macrophage colony-stimulating factor (GM-CSF) as a DNA vaccine platform in mouse tumor models with different types of major histocompatibility antigen complex (MHC). Intraperitoneally administrated polyplex micelles were predominantly found in the lymph nodes, spleen, and liver. Compared with mock controls, the triple gene vaccine significantly prolonged the survival of mice harboring peritoneal dissemination of CT26 colorectal cancer cells, of which long-term surviving mice showed complete rejection when re-challenged with CT26 tumors. Moreover, the DNA vaccine inhibited the growth and metastasis of subcutaneous CT26 and Lewis lung tumors in BALB/c and C57BL/6 mice, respectively, which represent different MHC haplotypes. The DNA vaccine highly stimulated both cytotoxic T lymphocyte and natural killer cell activities, and increased the infiltration of CD11c⁺ DCs and CD4⁺/CD8a⁺ T cells into tumors. Depletion of CD4⁺ or CD8a⁺ T cells by neutralizing antibodies deteriorated the anti-tumor efficacy of the DNA vaccine. In conclusion, a SART3/CD40L+GM-CSF gene-loaded polyplex micelle can be applied as a novel vaccine platform to elicit tumor rejection immunity regardless of the recipient MHC haplotype.

Floxuridine-loaded silk fibroin nanospheres

A clinical used anti-cancer drug floxuridine was successfully encapsulated in silk fibroin nanospheres. Such drug-loaded nanospheres have controllable size, fair drug-loading capacity and controlled release property, which maybe a good candidate for lymphatic chemotherapy.

Role of size of drug delivery carriers for pulmonary and intravenous administration with emphasis on cancer therapeutics and lung-targeted drug delivery

The design of a drug delivery system and the fabrication of efficient, successful, and targeted drug carriers are two separate issues that require slightly different design parameters.

Passive lung-targeted drug delivery systems via intravenous administration

The treatment of lung diseases including lung cancer and tuberculosis is one of the most challenging problems in clinical practice, because the conventional drug delivery systems cannot deliver drug effectively to the lung, which result in low therapeutic effect. Therefore, lung-targeted drug delivery systems (LTDDS) that can deliver drug to the lung in an effective way to increase drug concentration in lung tissue and reduce drug distribution in other organs and tissues become an ideal strategy to treat lung diseases. The LTDDS mainly include microparticles (microspheres and microencapsules), liposomes and nanoparticles via intravenous administration, and dry powder carriers and nebulized suspensions via pulmonary inhalation. As lungs possess the large absorptive surface area, the low thickness of the epithelial barrier and good blood supply, pulmonary inhalation has received great attention. Intravenous route is the commonly practiced method for administration of larger doses of drugs into the body. Numerous drugs can be delivered directly into general circulation by avoiding their first-pass metabolism and have potential to transport drugs to the lung via intravenous administration. This present article reviews the development, evaluation and application of LTDDS via intravenous administration for the treatment of lung diseases reported in the past decades.

Nanocrystals for the parenteral delivery of poorly water-soluble drugs

Nanocrystals have drawn increasing interest in pharmaceutical industry because of the ability to improve dissolution of poorly water-soluble drugs. Nanocrystals can be produced by top-down and bottom-up technologies and have been explored for a variety of therapeutic applications. Here we review the methods of nanocrystal production and parenteral applications of nanocrystals. We also discuss remaining challenges in the development of nanocrystal products.

Structure-dependent immunostimulatory effect of CpG oligodeoxynucleotides and their delivery system

Unmethylated cytosine-phosphate-guanosine (CpG) oligodeoxynucleotides (ODNs) are recognized by Toll-like receptor 9 (TLR9) found in antigen-presenting cells and B cells and can activate the immune system. Using CpG ODNs as an adjuvant has been found to be effective for treating infectious diseases, cancers, and allergies. Because natural ODNs with only a phosphodiester backbone are easily degraded by nuclease (deoxyribonuclease [DNase]) in serum, CpG ODNs with a phosphorothioate backbone have been studied for clinical application. CpG ODNs with a phosphorothioate backbone have raised concern regarding undesirable side effects; however, several CpG ODNs with only a phosphodiester backbone have been reported to be stable in serum and to show an immunostimulatory effect. In recent years, research has been conducted on delivery systems for CpG ODNs using nanoparticles (NPs). The advantages of NP-based delivery of CpG ODN include (1) it can protect CpG ODN from DNase, (2) it can retain CpG ODN inside the body for a long period of time, (3) it can improve the cellular uptake efficiency of CpG ODN, and (4) it can deliver CpG ODN to the target tissues. Because the target cells of CpG ODN are cells of the immune system and TLR9, the receptor of CpG ODN is localized in endolysosomes, CpG ODN delivery systems are required to have qualities different from other nucleic acid drugs such as antisense DNA and small interfering RNA. Studies until now have reported various NPs as carriers for CpG ODN delivery. This review presents DNase-resistant CpG ODNs with various structures and their immunostimulatory effects and also focuses on delivery systems of CpG ODNs that utilize NPs. Because CpG ODNs interact with TLR9 and activate both the innate and the adaptive immune system, the application of CpG ODNs for the treatment of cancers, infectious diseases, and allergies holds great promise.

Effective transgene expression without toxicity by intraperitoneal administration of PEG-detachable polyplex micelles in mice with peritoneal dissemination

Block copolymer of poly(ethylene glycol)-block-poly{N-[N-(2-aminoethyl)-2-aminoethyl]aspartamide} (PEG-P[Asp(DET)]) has been originally introduced as a promising gene carrier by forming a nanomicelle with plasmid DNA. In this study, the polyplex micelle of PEG-SS-P[Asp(DET)], which disulfide linkage (SS) between PEG and cationic polymer can detach the surrounding PEG chains upon intracellular reduction, was firstly evaluated with respect to in vivo transduction efficiency and toxicity in comparison to that of PEG-P[Asp(DET)] in peritoneally disseminated cancer model. Intraperitoneal (i.p.) administration of PEG-SS-P[Asp(DET)] polyplex micelles showed a higher (P<0.05) transgene expression compared with PEG-P[Asp(DET)] in tumors. In contrast, the delivered distribution of the micelles was not different between the two polyplex micelles. PEG-SS-P[Asp(DET)] micelle encapsulating human tumor necrosis factor α (hTNF-α) gene exhibits a higher antitumor efficacy against disseminated cancer compared with PEG-P[Asp(DET)] or saline control. No hepatic and renal toxicities were observed by the administration of polyplex micelles. In conclusion, PEG-detachable polyplex micelles may represent an advantage in gene transduction in vivo over PEG-undetachable polyplex micelles after i.p. administration for peritoneal dissemination of cancer.