Pharmacokinetics and tumor uptake of a derivatized form of paclitaxel associated to a cholesterol-rich nanoemulsion (LDE) in patients with gynecologic cancers

Structural characterization of cholesterol-rich nanoemulsion (LDE)

Cholesterol-rich nanoemulsion (LDE) can carry chemotherapeutic agents in the circulation and can concentrate those agents in the neoplastic and inflammatory tissues. This method improves the biodistribution of the drug and reduces toxicity. However, the structural stability of LDE particles, without or with associated drugs, has not been extensively investigated. The aim of the present study is to investigate the structural stability of LDE and LDE associated to paclitaxel, etoposide or methotrexate in aqueous solution over time by small-angle X-ray scattering (SAXS and Ultra SAXS) and dynamic light scattering (DLS). The results show that LDE and LDE associated with those chemotherapeutic agents had reproducible and stable particle diameter, physical structure, and aggregation behavior over 3-month observation period. As estimated from both DLS and Ultra-SAXS methods, performed at pre-established intervals, the average particle diameter of LDE alone was approx. 32 nm, of LDE-paclitaxel was 31 nm, of LDE-methotrexate was 35 nm and of LDE-etoposide was 36 nm. Ultra-SAXS analysis showed that LDE nanoparticles were quasi-spherical, and SAXS showed that drug molecules inside the particles showed a layered-like organization. Formulations of LDE with associated PTX, ETO or MTX were successfully tested in animal experiments and in patients with cancer or with cardiovascular disease, showing markedly low toxicity, good tolerability and possible superior pharmacological action. Our results may be useful for ensuing clinical trials of this novel Nanomedicine tool, by strengthening the knowledge of the structural aspects of those LDE formulations.

Lipid-core nanoparticles: Classification, preparation methods, routes of administration and recent advances in cancer treatment

Nanotechnological drug delivery platforms represent a new paradigm for cancer therapeutics as they improve the pharmacokinetic profile and distribution of chemotherapeutic agents over conventional formulations. Among nanoparticles, lipid-based nanoplatforms possessing a lipid core, that is, lipid-core nanoparticles (LCNPs), have gained increasing interest due to lipid properties such as high solubilizing potential, versatility, biocompatibility, and biodegradability. However, due to the wide spectrum of morphologies and types of LCNPs, there is a lack of consensus regarding their terminology and classification. According to the current state-of-the-art in this critical review, LCNPs are defined and classified based on the state of their lipidic components in liquid lipid nanoparticles (LLNs). These include lipid nanoemulsions (LNEs) and lipid nanocapsules (LNCs), solid lipid nanoparticles (SLNs) and nanostructured lipid nanocarriers (NLCs). In addition, we present a comprehensive and comparative description of the methods employed for their preparation, routes of administration and the fundamental role of physicochemical properties of LCNPs for efficient antitumoral drug-delivery application. Market available LCNPs, clinical trials and preclinical in vivo studies of promising LCNPs as potential treatments for different cancer pathologies are summarized.

Use of paclitaxel carried in lipid core nanoparticles in patients with late-stage solid cancers with bone metastases: Lack of toxicity and therapeutic benefits

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LDE-PTX at 175 mg/m²/3wk dose was devoid of toxicity at > 3rd line treatment.

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Among 18 LDE-PTX treated patients, 9 had PFS > 6 months and 2 had PFS > 1 yr.

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LDE-PTX diminished bone pain and improved quality of life in all treated patients.

^{Patients with heavily pretreated, late-stage cancer and bone metastasis are usually poor candidates for further chemotherapy. Previously, we showed that association to lipid nanoparticles (LDE) drastically decreases the toxicity of anti-cancer drugs. Here, we tested the hypothesis that paclitaxel (PTX) carried in LDE could benefit end-of-life patients with painful bone metastases that had been previously treated with conventional PTX. Methods: Eighteen consecutive patients with late-stage cancer, 8 with breast, 5 with prostate and 5 with lung carcinoma, aged 59±9 years, were included in this study. All were receiving opioid medication. LDE-PTX was administered at 175 mg/m 2 every 3 weeks until disease progression. Clinical imaging examinations and serum biochemistry determinations were performed to monitor disease progression. Intensity of bone pain, use of opioid medications and occurrence of pathological bone fractures were also evaluated. Results: In total, 104 chemotherapy cycles were performed and none of the patients showed clinical and laboratorial toxicities or pathological bone fractures. In all patients, pain was reduced so as to allow substitution of non-opioid for opioid medication. Median progression-free survival (PFS) was four months (95% CI 2.4-5.5), but in five patients PFS was longer than 6 months. Conclusions: Absence of observable clinical and laboratorial toxicities from LDE-PTX treatment, improvement of bone pain and the possible effect on PFS in some patients, despite previous use of conventional PTX, suggest that LDEPTX merits further clinical investigation.}

Uptake of lipid core nanoparticles by fragments of tissues collected during cerebral tumor excision surgeries: hypotheses for use in drug targeting therapy

PURPOSE

Malignant cerebral tumors have poor prognosis and the blood-brain barrier is a major hindrance for most drugs to reach those tumors. Lipid nanoparticles (LDE) that bind to lipoprotein receptors may carry anticancer drugs and penetrate the cells through those receptors that are overexpressed in gliomas. The aim was to investigate the in vivo uptake of LDE by human cerebral tumors.

METHODS

Twelve consecutive patients (4 with glioblastomas, 1 meduloblastoma, 1 primary lymphoma, 2 with non-cerebral metastases and 4 with benign tumors) scheduled for tumor excision surgery were injected intravenously, 12 h before surgery, with LDE labeled ¹⁴C-cholesterol oleate. Fragments of tumors and of normal head tissues (muscle, periosteum, dura mater) discarded by the surgeon were submitted to lipid extraction and radioactive counting.

RESULTS

Tumor LDE uptake (range: 10-283 d.p.m./g of tissue) was not lower than that of normal tissues (range: 20-263 d.p.m./g). Malignant tumor uptake was threefold greater than benign tumor uptake (140 ± 93 vs 46 ± 18 d.p.m./g, p < 0.05). Results show that LDE can concentrate in brain malignant tumors and may be used to carry drugs directed against those tumors.

CONCLUSION

As LDE was previously shown to markedly decrease drug toxicity this new therapeutic strategy should be tested in future trials.

Use of paclitaxel carried in solid lipid nanoparticles to prevent peritoneal fibrosis in rats

Background

Progressive fibrous thickening of peritoneal membrane (PM) is a major complication of long-term peritoneal dialysis. TGF-β/SMAD pathway activation, inflammation and neoangiogenesis have an important role in PM changes induced by peritoneal dialysis. Here, we investigated the effects of paclitaxel (PTX) carried in lipid core nanoparticles (LDE) on the development of peritoneal fibrosis (PF) in rats.

Methods

To induce PF, 21 male Wistar rats (300-350g) were injected with chlorhexidine gluconate for 15 consecutive days and randomly assigned to three groups: 1)PF, n = 5: no treatment; 2)LDE, n = 8: treated with LDE only, 3/3 days during 15 days; 3)LDE-PTX, n = 8: treated with PTX (4mg/kg) associated with LDE, 3/3 days during 15 days. A Control group without PF induction (n = 5) was designed, received saline solution, 3/3 days. Peritoneum function tests were performed, and anterior abdominal wall samples of the PM were collected for analyses of peritoneal thickness, immunohistochemitry, and gene expression.

Results

LDE-PTX treatment preserved the membrane function, maintaining the ultrafiltration rate and mass transfer of glucose at normal levels. LDE-PTX also prevented PM thickening induced by chlorhexidine gluconate injections. LDE-PTX treatment reduced the number of myofibroblasts infiltrating PM and inhibited the cell proliferation. Gene expression of fibronectin, FSP-1, VEGF, TGF-β, and SMAD3 were reduced by LDE-PTX.

Conclusions

LDE-PTX was effective to prevent development of PF and preserve the PM filtration capacity in this rat model, with clear-cut actions on pro-fibrotic mechanisms. Thus, LDE-PTX can be candidate for future clinical trials as adjuvant to peritoneal dialysis to prevent PF development, since this preparation is devoid of toxicity as shown previously.

Targeted drug delivery in cervical cancer: Current perspectives

Cervical cancer is preventable yet one of the most prevalent cancers among women around the globe. Though regular screening has resulted in the decline in incidence, the disease claims a high number of lives every year, especially in the developing countries. Owing to rather aggressive and non-specific nature of the conventional chemotherapeutics, there is a growing need for newer treatment modalities. The advent of nanotechnology has assisted in this through the use of nanocarriers for targeted drug delivery. A number of nanocarriers are continuously being developed and studied for their application in drug delivery. The present review summarises the different drug delivery approaches and nanocarriers that can be useful, their advantages and limitation.

Cholesterol-rich nanoemulsion (LDE) as a novel drug delivery system to diagnose, delineate, and treat human glioblastoma

We have prepared and characterized a cholesterol-rich nanoemulsion called LDE, a mimic of classic lipoprotein macromolecules, that can be applied as a new drug delivery system for aluminum phthalocyanine chloride (PcAlCl). The LDE containing PcAlCl system prepared herein had mean size and zeta potential of 127 nm and -29 mV, respectively, and encapsulation rate efficiency was 81%, and stability of 17 months. Compared to classical liposomes, LDE was more efficient, especially in brain diseases like glioblastoma (GBM), as revealed by tests on the U-87 MG cell line. The LDEPc formulation did not display dark cytotoxicity, as expected. The best light dose for LDEPc was 1.0 J·cm^-2: its activity was 55% higher than PcAlCl in a compatible organic medium. In the U-87 MG cells, apoptosis was the preferential pathway activated by PDT. These results strongly support the use of LDE as a new theranostic system.

Emerging insights on drug delivery by fatty acid mediated synthesis of lipophilic prodrugs as novel nanomedicines

Many drug molecules that are currently in the market suffer from short half-life, poor absorption, low specificity, rapid degradation, and resistance development. The design and development of lipophilic prodrugs can provide numerous benefits to overcome these challenges. Fatty acids (FAs), which are lipophilic biomolecules constituted of essential components of the living cells, carry out many necessary functions required for the development of efficient prodrugs. Chemical conjugation of FAs to drug molecules may change their pharmacodynamics/pharmacokinetics in vivo and even their toxicity profile. Well-designed FA-based prodrugs can also present other benefits, such as improved oral bioavailability, promoted tumor targeting efficiency, controlled drug release, and enhanced cellular penetration, leading to improved therapeutic efficacy. In this review, we discuss diverse drug molecules conjugated to various unsaturated FAs. Furthermore, various drug-FA conjugates loaded into various nanostructure delivery systems, including liposomes, solid lipid nanoparticles, emulsions, nano-assemblies, micelles, and polymeric nanoparticles, are reviewed. The present review aims to inspire readers to explore new avenues in prodrug design based on the various FAs with or without nanostructured delivery systems.

Novel Approach for Bone Marrow Transplantation Conditioning in Acute Myelogenous Leukemia not Responding to the Induction Therapy Using Etoposide Carried in Lipid Core Nanoparticles: A Pilot Clinical Study

Allogeneic hematopoietic cell transplantation (HCT) is the treatment of choice for acute myelogenous leukemia (AML) not responding to induction therapy. It is a therapeutic choice for the blast phase of chronic myelogenous leukemia (CML-BP) in patients failing to respond to tyrosine kinase inhibitors (TKIs). Lipid core nanoparticles (LDEs) concentrate severalfold more in blast cells than in corresponding normal cells. Incorporation of anticancer drugs to LDE formulations increases the pharmacologic action and decreases the toxicity. We tested a drug-targeting system, LDE-etoposide plus total body irradiation (TBI; 1200 cGy dose), in 13 patients with AML not responding to the induction therapy and in 2 patients with CML-BP refractory to second-generation TKIs. The mean patient age was 46.7 years (range, 22 to 66 years). The LDE-etoposide dose was escalated at 20, 30, 40, 50, and 60 mg/kg. No patients developed grade 4 or 5 toxicity; however, mucositis grade 3 occurred in 6 patients, 3 patients experienced diarrhea, and 1 patient had an elevated total bilirubin level. No deaths were related to conditioning. All patients were successfully engrafted. The median times to neutrophil and platelet engraftment were 20 ± 5 days and 16 ± 4 days, respectively. Five patients (33.4%) had acute graft-versus-host-disease (GVHD), including 4 grade I, and 1 with grade II, and 8 patients (57.1%) had moderate-to-severe chronic GVHD. This pilot study shows the potential of LDE-etoposide plus TBI as an HCT conditioning regimen in AML patients not responding to the induction and refractory therapies for CML-BP patient. These findings pave the way for subsequent larger clinical trials.

Therapeutic efficacy of nanoparticles and routes of administration

In modern-day medicine, nanotechnology and nanoparticles are some of the indispensable tools in disease monitoring and therapy. The term “nanomaterials” describes materials with nanoscale dimensions (< 100 nm) and are broadly classified into natural and synthetic nanomaterials. However, “engineered” nanomaterials have received significant attention due to their versatility. Although enormous strides have been made in research and development in the field of nanotechnology, it is often confusing for beginners to make an informed choice regarding the nanocarrier system and its potential applications. Hence, in this review, we have endeavored to briefly explain the most commonly used nanomaterials, their core properties and how surface functionalization would facilitate competent delivery of drugs or therapeutic molecules. Similarly, the suitability of carbon-based nanomaterials like CNT and QD has been discussed for targeted drug delivery and siRNA therapy. One of the biggest challenges in the formulation of drug delivery systems is fulfilling targeted/specific drug delivery, controlling drug release and preventing opsonization. Thus, a different mechanism of drug targeting, the role of suitable drug-laden nanocarrier fabrication and methods to augment drug solubility and bioavailability are discussed. Additionally, different routes of nanocarrier administration are discussed to provide greater understanding of the biological and other barriers and their impact on drug transport. The overall aim of this article is to facilitate straightforward perception of nanocarrier design, routes of various nanoparticle administration and the challenges associated with each drug delivery method.

Regression of Atherosclerotic Plaques of Cholesterol-Fed Rabbits by Combined Chemotherapy With Paclitaxel and Methotrexate Carried in Lipid Core Nanoparticles

In previous studies, it was demonstrated that lipid core nanoparticles (LDE) resemble the low-density lipoprotein structure and carrying the antiproliferative agent paclitaxel (PTX) strongly reduced atherosclerosis lesions induced in rabbits by cholesterol feeding. Currently, the aim was to verify whether combining LDE-PTX treatment with methotrexate (MTX) associated with LDE (LDE-MTX) could accelerate the atherosclerosis regression attained with single LDE-PTX treatment, after withdrawing the cholesterol feeding. Thirty-eight rabbits were fed 1% cholesterol chow for 8 weeks. Six of these rabbits were then euthanized for analyses of the aorta (controls). In the remaining rabbits, cholesterol feeding was withdrawn, and those 32 animals were allocated to 3 groups submitted to different 8-week intravenous treatments, all once/week: LDE-PTX (n = 10; 4 mg/kg), LDE-PTX + LDE-MTX (n = 11; 4 mg/kg), and LDE-alone (n = 11). Rabbits were then euthanized and aortas were excised for morphometric, immunohistochemical, and gene expression analyses. After cholesterol feeding withdrawal, in comparison with LDE-alone group, both LDE-PTX and LDE-PTX + LDE-MTX treatments had the ability to increase the regression of plaque areas: -49% in LDE-PTX and -59% for LDE-PTX + LDE-MTX. However, only LDE-PTX + LDE-MTX treatment elicited reduction in the intima area, estimated in -57%. Macrophage presence in aortic lesions was reduced 48% by LDE-PTX and 43% by LDE-PTX + LDE-MTX treatment. Matrix metalloproteinase 9 was reduced by either LDE-PTX (74%) or LDE-PTX + LDE-MTX (78%). Tumor necrosis factor α gene expression was reduced 65% by LDE-PTX and 79% by LDE-PTX + LDE-MTX. In conclusion, treatment with LDE-PTX indeed accelerated plaque reduction after cholesterol feeding; LDE-PTX + LDE-MTX further increased this effect, without any observed toxicity. These results pave the way for the use of combined chemotherapy to achieve stronger effects on aggravated, highly inflamed atherosclerotic lesions.

Lipid core nanoparticles resembling low-density lipoprotein and regression of atherosclerotic lesions: effects of particle size

Particles are usually polydispersed and size is an important feature for lipid-based drug delivery systems in order to optimize cell-particle interactions as to pharmacologic action and toxicity. Lipid nanoparticles (LDE) with composition similar to that of low-density lipoprotein carrying paclitaxel were shown to markedly reduce atherosclerosis lesions induced in rabbits by cholesterol feeding. The aim of this study was to test whether two LDE fractions, one with small (20-60 nm) and the other with large (60-100 nm) particles, had different actions on the atherosclerotic lesions. The two LDE-paclitaxel fractions, prepared by microfluidization, were separated by density gradient ultracentrifugation and injected (4 mg/body weight, intravenously once a week) into two groups of rabbits previously fed cholesterol for 4 weeks. A group of cholesterol-fed animals injected with saline solution was used as control to assess lesion reduction with treatment. After the treatment period, the animals were euthanized for analysis. After treatment, both the small and large nanoparticle preparations of LDE-paclitaxel had equally strong anti-atherosclerosis action. Both reduced lesion extension in the aorta by roughly 50%, decreased the intima width by 75% and the macrophage presence in the intima by 50%. The two preparations also showed similar toxicity profile. In conclusion, within the 20-100 nm range, size is apparently not an important feature regarding the LDE nanoparticle system and perhaps other solid lipid-based systems.

Nanomedicine for prostate cancer using nanoemulsion: A review

Prostate cancer (PCa) is a worldwide issue, with burgeoning rise in prevalence, morbidity and mortality. Targeted drug delivery, a long sort solution in this regard using controlled release (CR) - nanocarriers, is still a challenge. There is an emerging criticism that, the challenges are due to less appreciation for the biological barriers and lack of corresponding newer technologies. Over the years, more understanding about the biological barriers has come with the progress in characterization techniques. Correspondingly, there is a change in opinion about approaches in clinical trial that; focus of the end point need to be shifted towards disease stabilization for these explorative technologies. Currently, there is a requirement to overcome these newly identified challenges to develop newer affordable therapeutics. The ongoing clinical protocol for therapy using CR-nanocarriers is intravenous injection followed by local targeting to cancer site. This is the most accepted protocol and new CR-nanocarriers are being developed to suit this protocol. In this review, recent progress in treatment of PCa using CR-nanocarriers is analyzed with respect to newly identified biological barriers and design challenges. Possibilities of exploring nanoemulsion (NE) platform for targeted drug delivery to PCa are examined. Repurposing of drugs and combination therapy using NE platform targeted to PCa can be explored for design and development of affordable nanomedicine. In 20yrs. from now there expected to be numerous affordable nanomedicine technologies available in market exploring these lines.

Organic effects of associating paclitaxel with a lipid-based nanoparticle system on a nonhuman primate, Cebus apella

Lipid-based nanoparticle systems have been used as vehicles for chemotherapeutic agents in experimental cancer treatments. Those systems have generally been credited with attenuating the severe toxicity of chemotherapeutic agents. This study aimed to investigate the effects of associating paclitaxel (PTX) with a lipid-based nanoparticle system on a nonhuman primate, Cebus apella, documenting the toxicity as measured by serum biochemistry, which is a detailed analysis of blood and tissue. Eighteen C. apella were studied: three animals were treated with cholesterol-rich nanoemulsion (LDE) only, without PTX, administered intravenously every 3 weeks, during six treatment cycles; six animals were treated with PTX associated with LDE at the same administration scheme, three with lower (175 mg/m²) and three with higher (250 mg/m²) PTX doses; and six animals were treated with commercial PTX, three with the lower and three with the higher doses. In the LDE-PTX group, no clinical toxicity appeared, and the weight-food consumption curve was similar to that of the controls. Two animals treated with commercial PTX presented weight loss, nausea and vomiting, diarrhea, skin flaking, 70% loss of body hair, and decreased physical activity. The use of LDE as a carrier at both lower and higher doses reduced the toxicity of the drug in this species, which is closely related to human subjects. This was observed not only by clinical, biochemical, and hematological profiles but also by the histopathological analysis. The results of this study support the assumption that lipid-based nanoparticle systems used as drug carriers can serve as valuable tools to decrease the toxicity and increase the safety of chemotherapeutic agents.

Evaluation of atherosclerotic lesions in cholesterol-fed mice during treatment with paclitaxel in lipid nanoparticles: a magnetic resonance imaging study

Cholesterol-core nanoparticles (LDE) have been shown to be recognized by low-density lipoprotein receptors (LDLR) after administration; therefore, LDE is an ideal vehicle to deliver drug with targeting property. Paclitaxel, when incorporated into LDE, promotes atherosclerosis regression with reduced drug toxicity in rabbits through LDLR. Here, we tested whether LDE-paclitaxel could still be effective in reducing diet-induced atherosclerosis in a mouse model without LDLR. Nineteen LDLR knockout male mice were fed 1% cholesterol for 12 weeks. Then, 12 animals received 4-weekly intraperitoneal LDE-paclitaxel (4 mg/kg) while 7 controls received saline solution. On week 12 and 16, in vivo MRI of the aortic roots was performed. Aorta macroscopy was made after euthanasia. Reduction of atherosclerotic lesions was observed. LDE-paclitaxel treatment resulted in reduction of wall area (14%) and stenosis (22%) by MRI and 33% by macroscopy. Thus, LDE-paclitaxel may produce pharmacological effects through LDE uptake by mechanisms other than LDLR.

Lipid-Drug Conjugate for Enhancing Drug Delivery

Lipid-drug conjugates (LDCs) are drug molecules that have been covalently modified with lipids. The conjugation of lipids to drug molecules increases lipophilicity and also changes other properties of drugs. The conjugates demonstrate several advantages including improved oral bioavailability, improved targeting to the lymphatic system, enhanced tumor targeting, and reduced toxicity. Based on the chemical nature of drugs and lipids, various conjugation strategies and chemical linkers can be utilized to synthesize LDCs. Linkers and/or conjugation methods determine how drugs are released from LDCs and are critical for the optimal performance of LDCs. In this review, different lipids used for preparing LDCs and various conjugation strategies are summarized. Although LDCs can be administered without a delivery carrier, most of them are loaded into appropriate delivery systems. The lipid moiety in the conjugates can significantly enhance drug loading into hydrophobic components of delivery carriers and thus generate formulations with high drug loading and superior stability. Different delivery carriers such as emulsions, liposomes, micelles, lipid nanoparticles, and polymer nanoparticles are also discussed in this review.

Clinical experience with drug delivery systems as tools to decrease the toxicity of anticancer chemotherapeutic agents

INTRODUCTION

The toxicity of chemotherapeutic agents, resulting from their low pharmacological index, introduces considerable discomfort and risk to cancer patients. Among several strategies to reduce the toxicity of chemotherapeutic agents, targeted drug delivery is the most promising one. Areas covered: Liposomes, micelles, albumin-based, polymeric, dendritic and lipid core nanoparticles have been used as carriers to concentrate anticancer drugs in neoplastic tissues, and clinical studies of those preparations are reviewed. In most clinical studies, drug delivery systems reduced drug toxicity. Lipid core nanoparticles (LDE) that bind to cell lipoprotein receptors have the ability to concentrate in neoplastic tissues and were the first artificial non-liposomal system shown in in vivo studies to possess targeting properties. The toxicity reduction achieved by LDE as vehicle of carmustine, etoposide and paclitaxel was singularly strong. Expert opinion: The reduced toxicity offered by drug delivery systems has expanded treatment population that may benefit from chemotherapy including feeble, overtreated and elderly patients that would otherwise be offered palliative therapy. Drug delivery systems may either prolong the duration of treatments or allow increases in drug dose.

Synergistic inhibition of colon cancer cell growth with nanoemulsion-loaded paclitaxel and PI3K/mTOR dual inhibitor BEZ235 through apoptosis

Colon cancer is the third most common cancer in the world, with drug resistance and metastasis being the major challenges to effective treatments. To overcome this, combination therapy with different chemotherapeutics is a common practice. In this study, we demonstrated that paclitaxel (PTX) together with BEZ235 exhibited a synergetic inhibition effect on colon cancer cell growth. Furthermore, nanoemulsion (NE)-loaded PTX and BEZ235 were more effective than the free drug, and a combination treatment of both NE drugs increased the efficiency of the treatments. BEZ235 pretreatment before adding PTX sensitized the cancer cells further, suggesting a synergistic inhibition effect through the phosphatidylinositol-3-kinases/protein kinase B/mammalian target of rapamycin pathway. The 50% inhibitory concentrations for BEZ235 were 127.1 nM and 145.0 nM and for PTX 9.7 nM and 9.5 nM for HCT-116 and HT-29 cells, respectively. When loaded with NE the 50% inhibitory concentrations for BEZ235 decreased to 52.6 nM and 55.6 nM and for PTX to 1.9 nM and 2.3 nM for HCT-116 and HT-29 cells, respectively. Combination treatment with 10 nM NE-BEZ235 and 0.6 nM and 1.78 nM NE-PTX could kill 50% of HCT-116 and HT-29, respectively. The cell death caused by the treatment was through apoptotic cell death, which coincided with decreased expression of anti-apoptotic protein B-cell lymphoma 2. Our data indicate that the combination therapy of PTX with the phosphatidylinositol-3-kinases/protein kinase B/mammalian target of rapamycin dual inhibitor BEZ235 using NE delivery may hold promise for a more effective approach for colon cancer treatment.

Bioavailability enhancement and pharmacokinetic profile of an anticancer drug ibrutinib by self-nanoemulsifying drug delivery system

Objective

The current studies were undertaken to enhance dissolution and bioavailability/pharmacokinetic profile of a newly approved anticancer drug ibrutinib (IBR) via encapsulation of drug into self-nanoemulsifying drug delivery system (SNEDDS).

Methods

Various SNEDDS formulations of IBR were developed by aqueous phase titration method using Capryol-PGMC (oil phase), Tween-20 (surfactant), Carbitol (cosurfactant) and water (aqueous phase). Developed SNEDDS of IBR was evaluated in vitro for various physicochemical properties and drug release profile.

Key findings

Based on lowest droplet size (28.7 ± 3.2 nm), least polydispersity (0.123), optimal values of zeta potential (−32.8 mV) and refractive index (1.336), highest % transmittance (98.7 ± 0.2%), highest drug release profile via dialysis membrane (98.9 ± 8.2% after 48 h) and the presence of lowest concentration of Capryol-PGMC (12% w/w), SNEDDS I1 was selected for in-vivo pharmacokinetic/bioavailability studies in female Wistar rats. In-vivo pharmacokinetic studies in rats showed that optimized SNEDDS I1 controlled the absorption of IBR compared with IBR suspension. The bioavailability of IBR from optimized SNEDDS I1 was enhanced around 2.64 times in comparison with IBR suspension.

Conclusion

These results indicated the potential of developed SNEDDS as an alternative drug delivery system for IBR to enhance its bioavailability and anticancer efficacy.

Simvastatin increases the antineoplastic actions of paclitaxel carried in lipid nanoemulsions in melanoma-bearing mice

PURPOSE

Lipid nanoemulsions (LDEs) that bind to low-density lipoprotein (LDL) receptors used as carriers of paclitaxel (PTX) can decrease toxicity and increase PTX antitumoral action. The administration of simvastatin (Simva), which lowers LDL-cholesterol, was tested as an adjuvant to commercial PTX and to PTX associated with LDE (LDE-PTX).

MATERIALS AND METHODS

B16F10 melanoma-bearing mice were treated with saline solution or LDE (controls), Simva, PTX, PTX and Simva, LDE-PTX, and LDE-PTX and Simva: PTX dose 17.5 μmol/kg (three intraperitoneal injections, 3 alternate days): Simva 50 mg/kg/day by gavage, 9 consecutive days.

RESULTS

Compared with saline controls, 95% tumor-growth inhibition was achieved by LDE-PTX and Simva, 61% by LDE-PTX, 44% by PTX and Simva, and 43% by PTX. Simva alone had no effect. Metastasis developed in only 37% of the LDE-PTX and Simva, 60% in LDE-PTX, and 90% in PTX and Simva groups. Survival rates were higher in LDE-PTX and Simva and in LDE-PTX groups. The LDE-PTX and Simva group presented tumors with reduced cellular density and increased collagen fibers I and III. Tumors from all groups showed reduction in immunohistochemical expression of ICAM, MCP-1, and MMP-9; LDE-PTX and Simva presented the lowest MMP-9 expression. Expression of p21 was increased in the Simva, LDE-PTX, and LDE-PTX and Simva groups. In the Simva and LDE-PTX and Simva groups, expression of cyclin D1, a proliferation and survival promoter of tumor cells, was decreased. Therapy with LDE-PTX and Simva showed negligible toxicity compared with PTX and Simva, which resulted in weight loss and myelosuppression.

CONCLUSION

Simva increased the antitumor activity of PTX carried in LDE but not of PTX commercial presentation, possibly because statins increase the expression of LDL receptors that internalize LDE-PTX.

Anti-inflammatory effects of intravenous methotrexate associated with lipid nanoemulsions on antigen-induced arthritis

OBJECTIVE

To test the hypothesis that intravenous use of methotrexate associated with lipid nanoemulsions can achieve superior anti-inflammatory effects in the joints of rabbits with antigen-induced arthritis compared with commercial methotrexate.

METHODS

Arthritis was induced in New Zealand rabbits sensitized with methylated bovine serum albumin and subsequently intra-articularly injected with the antigen. A nanoemulsion of methotrexate labeled with 3H-cholesteryl ether (4 mg/kg methotrexate) was then intravenously injected into four rabbits to determine the plasma decaying curves and the biodistribution of the methotrexate nanoemulsion by radioactive counting. Additionally, the pharmacokinetics of the methotrexate nanoemulsion were determined by high-pressure liquid chromatography. Twenty-four hours after arthritis induction, the animals were allocated into three groups, with intravenous injection with saline solution (n=9), methotrexate nanoemulsion (0.5 µmol/kg methotrexate, n=7), or commercial methotrexate (0.5 µmol/kg, n=4). The rabbits were sacrificed 24 h afterward. Synovial fluid was then collected for protein leakage and cell content analyses and synovial membranes were collected for histopathological analysis.

RESULTS

The methotrexate nanoemulsion was taken up mainly by the liver and the uptake by arthritic joints was two-fold greater than that by control joints. The methotrexate nanoemulsion treatment reduced leukocyte influx into the synovial fluid by nearly 65%; in particular, mononuclear and polymorphonuclear cells were reduced by 47 and 72%, respectively. In contrast, cell influx was unaffected following treatment with commercial methotrexate. Protein leakage into the arthritic knees of the rabbits was also more limited following methotrexate nanoemulsion treatment than following commercial methotrexate treatment.

CONCLUSIONS

The intravenous methotrexate nanoemulsion showed anti-inflammatory effects on the synovia of arthritic joints that were clearly superior to the effects of a commercial methotrexate preparation. This result is conceivably due to greater methotrexate uptake by the joints when the drug is associated with a nanoemulsion.

Use of combined chemotherapy with etoposide and methotrexate, both associated to lipid nanoemulsions for atherosclerosis treatment in cholesterol-fed rabbits

PURPOSE

Treatment of atherosclerotic rabbits with intravenous methotrexate or etoposide carried in lipid nanoemulsions (LDE) markedly reduced the lesions in the aorta. Here, the combined treatment with LDE-methotrexate and LDE-etoposide was investigated aiming to increase the anti-atherosclerosis effect.

METHODS

Thirty-six male rabbits received a diet with 1 % cholesterol for 2 months. After the first month, the animals received 4 weekly intravenous injections of LDE-methotrexate (4 mg/kg dose), LDE-etoposide (6 mg/kg), or a combination of those two drugs, while the control animals were injected with LDE (n = 9 for each group).

RESULTS

LDE-methotrexate+LDE-etoposide reduced aortic lesion areas by 95 % compared with controls and the intima-media ratio was reduced five-fold, whereas LDE-methotrexate reduced the lesions by 81 % and LDE-etoposide by 83 %. Compared to controls, the positive area of macrophages and MMP-9 in the arterial intima was significantly reduced in all treated groups (p < 0.001), but the MMP9 reduction was greater with the combined chemotherapy than the reduction achieved by the isolated treatments. Presence of CD3 positive cells was equal in controls and LDE-methotrexate+LDE-etoposide treated animals. However, FOXP3 positive T lymphocytes in the intima were increased in the LDE-methotrexate+LDE-etoposide rabbits. Weight, food intake evolution and the hematologic parameters suggested that the treatment had very low toxicity.

CONCLUSIONS

Compared to the single treatments with LDE-methotrexate and LDE-etoposide, the combined treatment was more effective in reducing the atherosclerotic lesions. Because the toxicity of the novel drug-target combined scheme was low, those results favor the possibility of future clinical studies in patients with cardiovascular disease.

Drug delivery and drug targeting with parenteral lipid nanoemulsions - A review

Lipid nanosized emulsions or nanoemulsions (NE) are oil in water dispersions with an oil droplet size of about 200nm. This size of oil droplets dispersed in a continuous water phase is a prerequisite for the parenteral, namely intravenous administration. Many parenteral nutrition and drug emulsions on the market confirm the safe use of NE over years. Parenteral emulsions loaded with APIs (active pharmaceutical ingredients) are considered as drug delivery systems (DDS). DDS focuses on the regulation of the in vivo dynamics, such as absorption, distribution, metabolism, and extended bioavailability, thereby improving the effectiveness and the safety of the drugs. Using an emulsion as a DDS, or through the use of surface diversification of the dispersed oil droplets of emulsions, a targeted increase of the API concentration in some parts of the human body can be achieved. This review focuses on NE similar to the marketed once with no or only low amount of additional surfactants beside the emulsifier from a manufacturing point of view (technique, used raw materials).

In vitro and in vivo effects of free and chalcones-loaded nanoemulsions: insights and challenges in targeted cancer chemotherapies

Several obstacles are encountered in conventional chemotherapy, such as drug toxicity and poor stability. Nanotechnology is envisioned as a strategy to overcome these effects and to improve anticancer therapy. Nanoemulsions comprise submicron emulsions composed of biocompatible lipids, and present a large surface area revealing interesting physical properties. Chalcones are flavonoid precursors, and have been studied as cytotoxic drugs for leukemia cells that induce cell death by different apoptosis pathways. In this study, we encapsulated chalcones in a nanoemulsion and compared their effect with the respective free compounds in leukemia and in non-tumoral cell lines, as well as in an in vivo model. Free and loaded-nanoemulsion chalcones induced a similar anti-leukemic effect. Free chalcones induced higher toxicity in VERO cells than chalcones-loaded nanoemulsions. Similar results were observed in vivo. Free chalcones induced a reduction in weight gain and liver injuries, evidenced by oxidative stress, as well as an inflammatory response. Considering the high toxicity and the side effects induced generally by all cancer chemotherapies, nanotechnology provides some options for improving patients’ life quality and/or increasing survival rates.

Impact of process parameters in the generation of novel aspirin nanoemulsions--comparative studies between ultrasound cavitation and microfluidizer

In the present investigation, the operating efficiency of a bench-top air-driven microfluidizer has been compared to that of a bench-top high power ultrasound horn in the production of pharmaceutical grade nanoemulsions using aspirin as a model drug. The influence of important process variables as well as the pre-homogenization and drug loading on the resultant mean droplet diameter and size distribution of emulsion droplets was studied in an oil-in-water nanoemulsion incorporated with a model drug aspirin. Results obtained show that both the emulsification methods were capable of producing very fine nanoemulsions containing aspirin with the minimum droplet size ranging from 150 to 170 nm. In case of using the microfluidizer, it has been observed that the size of the emulsion droplets obtained was almost independent of the applied microfluidization pressure (200-600 bar) and the number of passes (up to 10 passes) while the pre-homogenization and drug loading had a marginal effect in increasing the droplet size. Whereas, in the case of ultrasound emulsification, the droplet size was generally decreased with an increase in sonication amplitude (50-70%) and period of sonication but the resultant emulsion was found to be dependent on the pre-homogenization and drug loading. The STEM microscopic observations illustrated that the optimized formulations obtained using ultrasound cavitation technique are comparable to microfluidized emulsions. These comparative results demonstrated that ultrasound cavitation is a relatively energy-efficient yet promising method of pharmaceutical nanoemulsions as compared to microfluidizer although the means used to generate the nanoemulsions are different.

A critical review of lipid-based nanoparticles for taxane delivery

Nano-based delivery systems have attracted a great deal of attention in the past two decades as a strategy to overcome the low therapeutic index of conventional anticancer drugs and delivery barriers in solid tumors. Myriads of preclinical studies have been focused on developing nano-based formulations to effectively deliver taxanes, one of the most important and most prescribed anticancer drug types in the clinic. Given the hydrophobic property of taxanes, lipid-based NPs, serve as a viable alternative delivery system. This critical review will provide an overview and perspective of the advancement of lipid-based nanoparticles for taxane delivery. Currently available formulations of taxanes and their drawbacks as well as criteria for idea taxane delivery system will be discussed.

Effect of neoadjuvant chemotherapy on low-density lipoprotein (LDL) receptor and LDL receptor-related protein 1 (LRP-1) receptor in locally advanced breast cancer

Low-density lipoprotein (LDL) receptors are overexpressed in most neoplastic cell lines and provide a mechanism for the internalization and concentration of drug-laden nanoemulsions that bind to these receptors. The aim of the present study was to determine whether the administration of standard chemotherapeutic schemes can alter the expression of LDL and LDL receptor-related protein 1 (LRP-1) receptors in breast carcinoma. Fragments of tumoral and normal breast tissue from 16 consecutive volunteer women with breast cancer in stage II or III were obtained from biopsies before the beginning of neoadjuvant chemotherapy and after chemotherapy, from fragments excised during mastectomy. Tissues were analyzed by immunohistochemistry for both receptors. Because complete response to treatment was achieved in 4 patients, only the tumors from 12 were analyzed. Before chemotherapy, there was overexpression of LDL receptor in the tumoral tissue compared to normal breast tissue in 8 of these patients. LRP-1 receptor overexpression was observed in tumors of 4 patients. After chemotherapy, expression of both receptors decreased in the tumors of 6 patients, increased in 4 and was unchanged in 2. Nonetheless, even when chemotherapy reduced receptors expression, the expression was still above normal. The fact that chemotherapy does not impair LDL receptors expression supports the use of drug carrier systems that target neoplastic cells by the LDL receptor endocytic pathway in patients on conventional chemotherapy.

Formulation development and optimization of a novel Cremophore EL-based nanoemulsion using ultrasound cavitation

In the present study, response surface methodology (RSM) based on central composite design (CCD) was employed to investigate the influence of main emulsion composition variables, namely drug loading, oil content, emulsifier content as well as the effect of the ultrasonic operating parameters such as pre-mixing time, ultrasonic amplitude, and irradiation time on the properties of aspirin-loaded nanoemulsions. The two main emulsion properties studied as response variables were: mean droplet size and polydispersity index. The ultimate goal of the present work was to determine the optimum level of the six independent variables in which an optimal aspirin nanoemulsion with desirable properties could be produced. The response surface analysis results clearly showed that the variability of two responses could be depicted as a linear function of the content of main emulsion compositions and ultrasonic processing variables. In the present investigation, it is evidently shown that ultrasound cavitation is a powerful yet promising approach in the controlled production of aspirin nanoemulsions with smaller average droplet size in a range of 200-300 nm and with a polydispersity index (PDI) of about 0.30. This study proved that the use of low frequency ultrasound is of considerable importance in the controlled production of pharmaceutical nanoemulsions in the drug delivery system.

Novel formulation of a methotrexate derivative with a lipid nanoemulsion

Background

Lipid nanoemulsions that bind to low-density lipoprotein receptors can concentrate chemotherapeutic agents in tissues with low-density lipoprotein receptor overexpression and decrease the toxicity of the treatment. The aim of this study was to develop a new formulation using a lipophilic derivative of methotrexate, ie, didodecyl methotrexate (ddMTX), associated with a lipid nanoemulsion (ddMTX-LDE).

Methods

ddMTX was synthesized by an esterification reaction between methotrexate and dodecyl bromide. The lipid nanoemulsion was prepared by four hours of ultrasonication of a mixture of phosphatidylcholine, triolein, and cholesteryloleate. Association of ddMTX with the lipid nanoemulsion was performed by additional cosonication of ddMTX with the previously prepared lipid nanoemulsion. Formulation stability was evaluated, and cell uptake, cytotoxicity, and acute animal toxicity studies were performed.

Results

The yield of ddMTX incorporation was 98% and the particle size of LDE-ddMTX was 60 nm. After 48 hours of incubation with plasma, approximately 28% ddMTX was released from the lipid nanoemulsion. The formulation remained stable for at least 45 days at 4°C. Cytotoxicity of LDE-ddMTX against K562 and HL60 neoplastic cells was higher than for methotrexate (50% inhibitory concentration [IC₅₀] 1.6 versus 18.2 mM and 0.2 versus 26 mM, respectively), and cellular uptake of LDE-ddMTX was 90-fold higher than that of methotrexate in K562 cells and 75-fold in HL60 cells. Toxicity of LDE-ddMTX, administered at escalating doses, was higher than for methotrexate (LD₅₀ 115 mg/kg versus 470 mg/kg; maximum tolerated dose 47 mg/kg versus 94 mg/kg) in mice. However, the hematological toxicity of LDE-ddMTX was lower than for methotrexate.

Conclusion

LDE-ddMTX was stable, and uptake of the formulation by neoplastic cells was remarkably greater than of methotrexate, which resulted in markedly greater cytotoxicity. LDE-ddMTX is thus a promising formulation to be tested in future animal models of cancer or rheumatic disease, wherein methotrexate is widely used.

Modification of composition of a nanoemulsion with different cholesteryl ester molecular species: effects on stability, peroxidation, and cell uptake

Purpose:

Use of lipid nanoemulsions as carriers of drugs for therapeutic or diagnostic purposes has been increasingly studied. Here, it was tested whether modifications of core particle constitution could affect the characteristics and biologic properties of lipid nanoemulsions.

Methods:

Three nanoemulsions were prepared using cholesteryl oleate, cholesteryl stearate, or cholesteryl linoleate as main core constituents. Particle size, stability, pH, peroxidation of the nanoemulsions, and cell survival and uptake by different cell lines were evaluated.

Results:

It was shown that cholesteryl stearate nanoemulsions had the greatest particle size and all three nanoemulsions were stable during the 237-day observation period. The pH of the three nanoemulsion preparations tended to decrease over time, but the decrease in pH of cholesteryl stearate was smaller than that of cholesteryl oleate and cholesteryl linoleate. Lipoperoxidation was greater in cholesteryl linoleate than in cholesteryl oleate and cholesteryl stearate. After four hours’ incubation of human umbilical vein endothelial cells (HUVEC) with nanoemulsions, peroxidation was minimal in the presence of cholesteryl oleate and more pronounced with cholesteryl linoleate and cholesteryl stearate. In contrast, macrophage incubates showed the highest peroxidation rates with cholesteryl oleate. Cholesteryl linoleate induced the highest cell peroxidation rates, except in macrophages. Uptake of cholesteryl oleate nanoemulsion by HUVEC and fibroblasts was greater than that of cholesteryl linoleate and cholesteryl stearate. Uptake of the three nanoemulsions by monocytes was equal. Uptake of cholesteryl oleate and cholesteryl linoleate by macrophages was negligible, but macrophage uptake of cholesteryl stearate was higher. In H292 tumor cells, cholesteryl oleate showed the highest uptakes. HUVEC showed higher survival rates when incubated with cholesteryl stearate and smaller survival with cholesteryl linoleate. H292 survival was greater with cholesteryl stearate.

Conclusion:

Although all three nanoemulsion types were stable for a long period, considerable differences were observed in size, oxidation status, and cell survival and nanoemulsion uptake in all tested cell lines. Those differences may be helpful in protocol planning and interpretation of data from experiments with lipid nanoemulsions.

Microemulsions as drug delivery systems to improve the solubility and the bioavailability of poorly water-soluble drugs

IMPORTANCE OF THE FIELD

Microemulsions have been studied extensively as potential drug delivery vehicles for poorly water-soluble drugs. An understanding of the physicochemical and biopharmaceutical characteristics of the microemulsions according to administration routes will provide guidance for designing the formulations of microemulsions.

AREAS COVERED IN THIS REVIEW

In this paper, the use and the characteristics of microemulsions as drug delivery vehicles are reviewed. As the formulations of the microemulsion always include a great amount of surfactant and co-surfactant, which may cause hemolysis or histopathological alterations of the tissue, the potential toxicity or the irritancy of microemulsions is also discussed in this paper.

WHAT THE READER WILL GAIN

Developments of microemulsions for poorly water-soluble drugs in recent years are included in this review. Several factors limiting the commercial or clinical use of microemulsions are also discussed.

TAKE HOME MESSAGE

Considering the potential in enhanced drug uptake/permeation and facing the limitations, their unique properties make microemulsions a promising vehicle for poorly water-soluble drugs.

Prospects and challenges of the development of lipoprotein-based formulations for anti-cancer drugs

This review evaluates drug delivery systems that involve intact plasma lipoproteins or some of their components. These complex macromolecules transport highly water-insoluble compounds (cholesteryl esters and triacylglycerols) in their natural environment - a property that renders them ideal carriers of hydrophobic drugs. Particular emphasis is placed on the application of lipoproteins as drug delivery agents in cancer chemotherapy. The history and present activity regarding lipoprotein-based formulations are reviewed, with the primary focus on the smaller sized (low and high density) lipoprotein-based formulations and their potential clinical and commercial value. The use of both native and synthetic lipoproteins as drug delivery agents are discussed from the standpoint of therapeutic efficacy, as well as commercial feasibility. The advantages of lipoprotein-based drug delivery formulations are compared with other drug delivery models, with the primary focus on liposomal preparations. Finally, an expert opinion is provided, regarding the potential use of lipoprotein-based formulations in cancer treatment, taking into consideration the major advantages (biocompatibility, safety, drug solubility) and the barriers (manufacturing protein components, financial interest, investments) to their commercial development.