In vivo biodistribution of edelfosine-loaded lipid nanoparticles radiolabeled with Technetium-99 m: Comparison of administration routes in mice.

Edelfosine (ET) is a potent antitumor agent but causes severe side effects that have limited its use in clinical practice. For this reason, nanoencapsulation in lipid nanoparticles (LNs) is advantageous as it protects from ET side-effects. Interestingly, previous studies showed the efficacy of LNs containing ET in various types of tumor. In this paper, biodistribution studies of nanoencapsulated ET, administered by three routes (oral, intravenous (IV) and intraperitoneal (IP)), were tested in order to select the optimal route of administration. To do this, ET-LNs were labeled with Technetium-99 m (99mTc) and administered by the oral, IV and IP route in mice. IV administration of the radiolabeled LNs led to fast elimination from the blood circulation and increased accumulation in reticulo-endothelial (RES) organs, while their oral administration could not provide any evidence on their biodistribution since large radiocomplexes were formed in the presence of gastrointestinal fluids. However, when the LNs were administered by the IP route they could access the systemic circulation and provided more constant blood ET-LN levels compared to the IV route. These findings suggest that the IP route can be used to sustain the level of drug in the blood and avoid accumulation in RES organs.

Lipid nanoparticles enhance the absorption of cyclosporine A through the gastrointestinal barrier: In vitro and in vivo studies.

In the present work, the feasibility of cyclosporine A lipid nanoparticles (CsA LN) for oral administration was investigated. Three CsA LN formulations were developed using Precirol as lipid matrix, one stabilized with Tween(®) 80 (Tw) and the other two with mixtures of phosphatidylcholine or Pluronic(®) F127 with taurocholate (Lec:TC and PL:TC, respectively). The physical characteristics of the LN were studied under gastrointestinal pH and their integrity was found to be dependent on the stabilizers. The in vitro intestinal permeability was assessed with a human colon adenocarcinoma cell model and in vivo pharmacokinetic and biodistribution studies were performed in Balb/c mice using Sandimmune Neoral(®) as reference. In vitro results showed the highest CsA permeability with the LN containing Lec:TC. In contrast, the best in vivo performance was achieved from the LN containing Tw. The bioavailability of CsA was matched and even enhanced with Precirol nanoparticles. This study suggests the suitability of LN as promising vehicles for CsA oral delivery.

Lipid nanoparticles protect from edelfosine toxicity in vivo.

Edelfosine, an alkyl-lysophospholipid antitumor drug with severe side-effects, has previously been encapsulated into lipid nanoparticles (LN) with the purpose of improving their toxicity profile. LN are made of lipids recognized as safe by the Food and Drug Administration (FDA) and, therefore, these systems are generally considered as nontoxic vehicles. However, toxicity studies regarding the use of LN as vehicles for drug administration are limited. In the present study, we investigated the in vivo toxicity of free edelfosine, and the protection conferred by LN. The free drug, non-loaded LN and edelfosine-loaded LN were orally administered to mice. Our results show that the oral administration of the free drug at 4 times higher than the therapeutic dose caused the death of the animals within 72h. Moreover, histopathology revealed gastrointestinal toxicity and an immunosuppressive effect. In contrast, LN showed a protective effect against edelfosine toxicity even at the higher dose and were completely safe. LN are, therefore, a safe vehicle for the administration of edelfosine by the oral route. The nanosystems developed could be further used for the administration of other drugs.

Edelfosine lipid nanoparticles overcome multidrug resistance in K-562 leukemia cells by a caspase-independent mechanism.

The antitumor ether lipid edelfosine is the prototype of a novel generation of promising anticancer drugs that has been shown to be an effective antitumor agent in numerous malignancies. However, several cancer types display resistance to different antitumoral compounds due to multidrug resistance (MDR). Thus, MDR is a major drawback in anticancer therapy. In that sense, the leukemic cell line K-562 shows resistance to edelfosine. This resistance is overcome by the use of nanotechnology. The present work describes the rate and mechanism of internalization of free and nanoencapsulated edelfosine. The molecular mechanisms underlying cell death are described in the present paper by characterization of several molecules implied in the apoptosic and autophagic pathways (PARP, LC3IIB, caspases-3, -9 and -7), and their pattern of expression is compared with the cell induction in a sensitive cell line HL-60. Results showed different internalization patterns in both cells. Clathrin and lipid raft mediated endocytosis were observable in edelfosine uptake, whereas these mechanism were not visible in the uptake of lipid nanoparticles, which might suffer phagocytosis and macropinocytosis. Both treatments induced caspase-mediated apoptosis in HL-60 cells, whereas this cell death mechanism was unnoticeable in K-562 cells. Moreover, an important increase in autophagic vesicles was visible in K-562 cells. Thus, this mechanism might be implicated in overcoming K-562 resistance with the treatment by lipid nanoparticles.

In vitro intestinal co-culture cell model to evaluate intestinal absorption of edelfosine lipid nanoparticles.

Nanotechnology is providing a new therapeutic paradigm by enhancing drug efficacy and preventing side-effects. Edelfosine is a synthetic ether lipid analogue of platelet activating factor with high antitumor activity. The encapsulation of this potent antitumor drug in lipid nanoparticles increases its oral bioavailability; moreover, it prevents the hemolytic and gastrointestinal side-effects of the free drug. The literature points towards lymphatic absorption of lipid nanoparticles after oral administration, and previous in vitro and in vivo studies stress the protection against toxicity that these nanosystems provide. The present study is intended to assess the permeability of lipid nanoparticles across the intestinal barrier. Caco-2 monoculture and Caco-2/Raji co-culture were used as in vitro models of enterocytes and Microfold cells respectively. Results showed that free drug is internalized and possibly metabolized in enterocytes. These results do not correlate with those observed in vivo when edelfosine-lipid nanoparticles were administered orally in mice, which suggests that the microfold model is not a good model to study the absorption of edelfosine-lipid nanoparticles across the intestinal barrier in vitro.

Efficacy of edelfosine lipid nanoparticles in breast cancer cells.

Breast cancer is a heterogeneous group of neoplasms predominantly originating in the terminal duct lobular units. It represents the leading cause of cancer death in women and the survival frequencies for patients at advanced stages of the disease remain low. New treatment options need to be researched to improve these rates. The anti-tumor ether lipid edelfosine (ET) is the prototype of a novel generation of promising anticancer drugs. However, it presents several drawbacks for its use in cancer therapy, including gastrointestinal and hemolytic toxicity and low oral bioavailability. To overcome these obstacles, ET was encapsulated in Precirol ATO 5 lipid nanoparticles (ET-LN), and its anti-tumor potential was in vitro tested in breast cancer. The formulated ET-LN were more effective in inhibiting cell proliferation and notably decreased cell viability, showing that the cytotoxic effect of ET was considerably enhanced when ET was encapsulated. In addition, ET and ET-LN were able to promote cell cycle arrest at G1 phase. Moreover, although both treatments provoked an apoptotic effect in a time-dependent manner, such anti-tumor effects were noticeably improved with ET-LN treatment. Therefore, our results indicate that encapsulating ET in LN played an essential role in improving the efficacy of the drug.

Edelfosine lipid nanosystems overcome drug resistance in leukemic cell lines.

Although current therapies have improved leukemia survival rates, adverse drug effects and relapse are frequent. Encapsulation of edelfosine (ET) in lipid nanoparticles (LNs) improves its oral bioavailability and decreases its toxicity. Here we evaluated the efficacy of ET-LN in myeloid leukemia cell lines. Drug-loaded LN were as effective as free ET in sensitive leukemia cell lines. Moreover, the encapsulated drug overcame the resistance of the K562 cell line to the drug. LN containing ET might be used as a promising drug delivery system in leukemia due to their capacity to overcome the in vivo pitfalls of the free drug and their efficacy in vitro in leukemia cell lines.

Lipid nanoparticles for cancer therapy: state of the art and future prospects.

INTRODUCTION: Cancer is a leading cause of death worldwide and it is estimated that deaths from this disease will rise to over 11 million in 2030. Most cases of cancer can be cured with surgery, radiotherapy or chemotherapy if they are detected at an early stage. However, current cancer therapies are commonly associated with undesirable side effects, as most chemotherapy treatments are cytotoxic and present poor tumor targeting. AREAS COVERED: Lipid nanoparticles (LN) are one of the most promising options in this field. LN are made up of biodegradable generally recognized as safe (GRAS) lipids, their formulation includes different techniques, and most are easily scalable to industrial manufacture. LN overcome the limitations imposed by the need for intravenous administration, as they are mainly absorbed via the lymphatic system when they are administered orally, which improves drug bioavailability. Furthermore, depending on their composition, LN present the ability to cross the blood-brain barrier, thus opening up the possibility of targeting brain tumors. EXPERT OPINION: The drawbacks of chemotherapeutic agents make it necessary to invest in research to find safer and more effective therapies. Nanotechnology has opened the door to new therapeutic options through the design of formulations that include a wide range of materials and formulations at the nanometer range, which improve drug efficacy through direct or indirect tumor targeting, increased bioavailability and diminished toxicity.