Design, synthesis and in silico molecular docking evaluation of novel 1,2,3-triazole derivatives as potent antimicrobial agents.

Chalcone and triazole scaffolds have demonstrated a crucial role in the advancement of science and technology. Due to their significance, research has proceeded on the design and development of novel benzooxepine connected to 1,2,3-triazolyl chalcone structures. The new chalcone derivatives produced by benzooxepine triazole methyl ketone 2 and different aromatic carbonyl compounds 3 are discussed in this paper. All prepared compounds have well-established structures to a variety of spectral approaches, including mass analysis, 1H NMR, 13C NMR, and IR. Among the tested compounds, hybrids 4c, 4d, 4i, and 4k exhibited exceptional antibacterial susceptibilities with MIC range of 3.59-10.30 µM against the tested S. aureus strain. Compounds 4c, 4d displayed superior antifungal activity against F. oxysporum with MIC 3.25, 4.89 µM, when compared to fluconazole (MIC = 3.83 µM) respectively. On the other hand, analogues 4d, 4f, and 4k demonstrated equivalent antitubercular action against H37Rv strain with MIC range of 2.16-4.90 µM. The capacity of ligand 4f to form a stable compound on the active site of CYP51 from M. tuberculosis (1EA1) was confirmed by docking studies using amino acids Leu321(A), Pro77(A), Phe83(A), Lys74(A), Tyr76(A), Ala73(A), Arg96(A), Thr80(A), Met79(A), His259(A), and Gln72(A). Additionally, the chalcone‒1,2,3‒triazole hybrids ADME (absorption, distribution, metabolism, and excretion), characteristics of molecules, estimations of toxicity, and bioactivity parameters were assessed.

In Vitro and In Vivo evaluation of a novel folate-targeted theranostic nanoemulsion of docetaxel for imaging and improved anticancer activity against ovarian cancers.

Ovarian cancer ranks fifth in cancer related deaths for women in USA. The high mortality rate associated with ovarian cancer is due to diagnosis at later stages of disease and the high recurrence rate of 60-80%. Recurrent ovarian cancers are more likely to present as multidrug resistance (MDR) leading to unfavorable response from 2nd and 3rd line chemotherapy. Nanoemulsions (NEs) are emerging as an attractive drug delivery system to overcome MDR challenges. NEs can also minimize exposure of therapeutic cargo to normal tissues potentially reducing side effects. In >80% of ovarian cancers, Folate Receptor-α (FR-α) is expressed at 10- to 100-fold higher levels than on non-pathological tissues. Therefore, folate (FA) is being evaluated as an active targeting moiety for FR-α+ ovarian cancer. To improve therapeutic outcome with reduced toxicity, we developed NMI-500, a FA targeted gadolinium (Gd) annotated NE loaded with docetaxel (DTX). NMI-500 has been developed as theranostic agents as Gd will enable physician to acquire real time pharmacodynamics data on NE + DTX accumulation in target lesions. In present study, characterization for key translational metrics of NMI-500 showed size distribution in range of 120 to 150 nm and zeta potential around -45 mV. Active targeting of FA was evaluated against FR-α+ KB cells and results demonstrated significant improvement in cell association which was surface ligand density dependent. We found that NMI-500 was able to inhibit tumor growth in a spontaneous transgenic ovarian cancer model with improved safety profile and this growth inhibition could be longitudinally followed by MRI. These results indicate NMI-500 warrants advancement to clinical trials.

Formulation development of a novel targeted theranostic nanoemulsion of docetaxel to overcome multidrug resistance in ovarian cancer.

OBJECTIVE: Ovarian cancer is a highly lethal disease in which the majority of patients eventually demonstrate multidrug resistance. Develop a novel active targeted theranostic nanomedicine designed to overcome drug efflux mechanisms, using a Generally Regarded As Safe (GRAS) grade nanoemulsion (NE) as a clinically relevant platform. MATERIALS AND METHODS: The NEs surface-functionalized with folate and gadolinium, were made using GRAS grade excipients and a high-shear microfluidization process. Efficacy was evaluated in ovarian cancer cells, SKOV3 and SKOV3TR. The NE accumulation in tumors was evaluated in SKOV3 tumor-bearing mice by magnetic resonance imaging (MRI). RESULTS AND DISCUSSION: The NE with particle size < 150 nm were stable in plasma and parenteral fluids for 24 h. Ovarian cancer cells in vitro efficiently took up the non-targeted and folate-targeted NEs; improved cytotoxicity was observed for the folate-targeted NEs showing a 270-fold drop in the IC50 in SKOV3TR cells as compared to docetaxel alone. The addition of gadolinium did not affect cell viability in vitro, but showed relaxation times comparable to Magnevist®. Folate-targeted NEs accumulated in tumors for prolonged period of time compared to Magnevist® and showed enhanced contrast compared to non-targeted NEs with MRI in SKOV3 tumor-bearing mice suggesting active targeting of NEs due to folate modification. CONCLUSIONS: A folate-targeted, theranostic NE delivers docetaxel by receptor mediated endocytosis that shows enhanced cytotoxicity capable of overcoming ABC transporter mediated taxane resistance. The diagnostic capability of the targeted nanomedicine showed enhanced contrast in tumors compared to clinically relevant MRI contrast agent Magnevist®.

EGFR Targeted Theranostic Nanoemulsion for Image-Guided Ovarian Cancer Therapy.

PURPOSE: Platinum-based therapies are the first line treatments for most types of cancer including ovarian cancer. However, their use is associated with dose-limiting toxicities and resistance. We report initial translational studies of a theranostic nanoemulsion loaded with a cisplatin derivative, myrisplatin and pro-apoptotic agent, C6-ceramide. METHODS: The surface of the nanoemulsion is annotated with an endothelial growth factor receptor (EGFR) binding peptide to improve targeting ability and gadolinium to provide diagnostic capability for image-guided therapy of EGFR overexpressing ovarian cancers. A high shear microfludization process was employed to produce the formulation with particle size below 150 nm. RESULTS: Pharmacokinetic study showed a prolonged blood platinum and gadolinium levels with nanoemulsions in nu/nu mice. The theranostic nanoemulsions also exhibited less toxicity and enhanced the survival time of mice as compared to an equivalent cisplatin treatment. CONCLUSIONS: Magnetic resonance imaging (MRI) studies indicate the theranostic nanoemulsions were effective contrast agents and could be used to track accumulation in a tumor. The MRI study additionally indicate that significantly more EGFR-targeted theranostic nanoemulsion accumulated in a tumor than non-targeted nanoemulsuion providing the feasibility of using a targeted theranostic agent in conjunction with MRI to image disease loci and quantify the disease progression.

Development of EGFR-targeted nanoemulsion for imaging and novel platinum therapy of ovarian cancer.

PURPOSE: Platinum-based chemotherapy is the treatment of choice for malignant epithelial ovarian cancers, but generalized toxicity and platinum resistance limits its use. Theranostic nanoemulsion with a novel platinum prodrug, myrisplatin, and the pro-apoptotic agent, C6-ceramide, were designed to overcome these limitations. METHODS: The nanoemulsions, including ones with an EGFR binding peptide and gadolinium, were made using generally regarded as safe grade excipients and a high shear microfluidization process. Efficacy was evaluated in ovarian cancer cells, SKOV3, A2780 and A2780CP. RESULTS: The nanoemulsion with particle size <150 nm were stable in plasma and parenteral fluids for 24 h. Ovarian cancer cells in vitro efficiently took up the non-targeted and EGFR-targeted nanoemulsions; improved cytotoxicity was observed for the these nanoemulsions with the latter showing a 50-fold drop in the IC50 in SKOV3 cells as compared to cisplatin alone. The addition of gadolinium did not affect cell viability in vitro, but showed relaxation times comparable to Magnevist(®). CONCLUSION: The myrisplatin/C6-ceramide nanoemulsion synergistically enhanced in vitro cytotoxicity. An EGFR binding peptide addition further increased in vitro cytotoxicity in EGFR positive cancer cells. The diagnostic version showed MR imaging similar to the clinically relevant Magnevist® and may be suitable as a theranostic for ovarian cancer.

Nanoemulsions in translational research-opportunities and challenges in targeted cancer therapy.

Nanoemulsion dosage form serves as a vehicle for the delivery of active pharmaceutical ingredients and has attracted great attention in drug delivery and pharmacotherapy. In particular, nanoemulsions act as an excellent vehicle for poorly aqueous soluble drugs, which are otherwise difficult to formulate in conventional dosage forms. Nanoemulsions are submicron emulsions composed of generally regarded as safe grade excipients. Particle size at the nanoscale and larger surface area lead to some very interesting physical properties that can be exploited to overcome anatomical and physiological barriers associated in drug delivery to the complex diseases such as cancer. Along these lines, nanoemulsions have been engineered with specific attributes such as size, surface charge, prolonged blood circulation, target specific binding ability, and imaging capability. These attributes can be tuned to assist in delivering drug/imaging agents to the specific site of interest, based on active and passive targeting mechanisms. This review focuses on the current state of nanoemulsions in the translational research and its role in targeted cancer therapy. In addition, the production, physico-chemical characterization, and regulatory aspects of nanoemulsion are addressed.

Role of integrated cancer nanomedicine in overcoming drug resistance.

Cancer remains a major killer of mankind. Failure of conventional chemotherapy has resulted in recurrence and development of virulent multi drug resistant (MDR) phenotypes adding to the complexity and diversity of this deadly disease. Apart from displaying classical physiological abnormalities and aberrant blood flow behavior, MDR cancers exhibit several distinctive features such as higher apoptotic threshold, aerobic glycolysis, regions of hypoxia, and elevated activity of drug-efflux transporters. MDR transporters play a pivotal role in protecting the cancer stem cells (CSCs) from chemotherapy. It is speculated that CSCs are instrumental in reviving tumors after the chemo and radiotherapy. In this regard, multifunctional nanoparticles that can integrate various key components such as drugs, genes, imaging agents and targeting ligands using unique delivery platforms would be more efficient in treating MDR cancers. This review presents some of the important principles involved in development of MDR and novel methods of treating cancers using multifunctional-targeted nanoparticles. Illustrative examples of nanoparticles engineered for drug/gene combination delivery and stimuli responsive nanoparticle systems for cancer therapy are also discussed.

Development of PIK-75 nanosuspension formulation with enhanced delivery efficiency and cytotoxicity for targeted anti-cancer therapy.

PIK-75 is a phosphatidylinositol 3-kinase (PI3K) inhibitor that shows selectivity toward p110-α over the other PI3K class Ia isoforms p110-ß and p110-δ, but it lacks solubility, stability and other kinase selectivity. The purpose of this study was to develop folate-targeted PIK-75 nanosuspension for tumor targeted delivery and to improve therapeutic efficacy in human ovarian cancer model. High pressure homogenization was used to prepare the non-targeted and targeted PIK-75 nanosuspensions which were characterized for size, zeta potential, entrapment efficiency, morphology, saturation solubility and dissolution velocity. In vitro analysis of drug uptake, cell viability and cell survival was conducted in SKOV-3 cells. Drug pharmacokinetics and pAkt expression were determined in SKOV-3 tumor bearing mice. PIK-75 nanosuspensions showed an improvement in dissolution velocity and an 11-fold increase in saturation solubility over pre-milled PIK-75. In vitro studies in SKOV-3 cells indicated a 2-fold improvement in drug uptake and 0.4-fold decrease in IC50 value of PIK-75 following treatment with targeted nanosuspension compared to non-targeted nanosuspension. The improvement in cytotoxicity was attributed to an increase in caspase 3/7 and hROS activity. In vivo studies indicated a 5-10-fold increased PIK-75 accumulation in the tumor with both the nanosuspension formulations compared to PIK-75 suspension. The targeted nanosuspension showed an enhanced downregulation of pAkt compared to non-targeted formulation system. These results illustrate the opportunity to formulate PIK-75 as a targeted nanosuspension to enhance uptake and cytotoxicity of the drug in tumor.

Anti-angiogenic and anti-cancer evaluation of betulin nanoemulsion in chicken chorioallantoic membrane and skin carcinoma in Balb/c mice.

Betulin (Bet), the main component of birch tree bark, has been recently reported to exert anticancer activity in several cell lines; however the underlying mechanisms are only partially elucidated. The aims of the present work were to assess the in vivo effects of betulin administered as nanoemulsion (NE) in two experimental models: (i) the chicken embryo chorioallantoic membrane (CAM) assay for the study of anti-angiogenic effects and (ii) the two-stage model of skin carcinoma induced in mice for the study of anti-tumor and anti-inflammatory effects, respectively. On the CAM of the chicken betulin in nanoemulsion (BetNE) shows a good penetrability at extra-embryonic tissue level, affecting both the chorioallantoic membrane as well as the yolk sac by reducing the capillary density. In the animal model, the potential impact of local application of betulin on the respiratory function of isolated liver mitochondria was further assessed. Topical application of betulin nanoemulsion for 12 weeks together with DMBA (7,12-dimethylbenz[a]anthracene) and TPA (12-O-tetradecanoylphorbol 13-acetate), as tumor initiator and promoter, enhanced the active respiration of isolated liver mitochondria. Betulin also inhibit skin tumor apparition and promotion, proved by histological results and VEGF (vascular endothelial growth factor) expression correlated to non-invasive measurements. Betulin is active in nanoemulsion formulation as a potential inhibitory on the angiogenic process in CAM assay. BetNE can develop a potent anti-inflammatory and anti-carcinogenic activity with a low toxicity at skin level. It can also influence the penetration of carcinogens and reduce damage in main organs (e.g., liver).

Synthesis and preliminary in vivo evaluations of polyurethane microstructures for transdermal drug delivery.

BACKGROUND: Polymers have been considered as important materials in fabrication of microstructures for various medical purposes including drug delivery. This study evaluates polyurethane as material for hollow microstructures preparation. RESULTS: Polyurethane microstructures were obtained by interfacial polyaddition combined with spontaneous emulsification and present slightly acid pH values. Scanning electron microscopy revealed the existence of irregular shapes and agglomerated microstructures. The material is heat resistant up to 280°C. Good results were recorded on murine skin tests in case of polyurethane microstructures based on isophorone diisocyanate. Mesenchymal stem cells viability presents good results for the same sample after 48 hours based on the Alamar Blue test. CONCLUSIONS: The research revealed the reduced noxiousness of this type of microstructures and consequently the possibility of their use for therapeutic purposes.

Multi-compartmental vaccine delivery system for enhanced immune response to gp100 peptide antigen in melanoma immunotherapy.

PURPOSE: To develop a multi-compartmental vaccine delivery system for safe and efficient delivery of the gp100 peptide antigen in melanoma immunotherapy. METHODS: Water-in-oil-in-water (W/O/W) multiple emulsion-based multi-compartmental vaccine delivery system containing the gp100 peptide was prepared by a two-step emulsification method. In vivo prophylactic and active immunization effectiveness of the novel squalane oil-containing gp100 vaccine was evaluated in the murine B16 melanoma model and compared with that of an incomplete Freund's adjuvant (IFA)-based vaccine. RESULTS: Morphological evaluation of the W/O/W multiple emulsions showed that the oil-droplets were homogenously dispersed with the gp100 peptide encapsulated in an inner aqueous phase. Immunization with the gp100 peptide delivered in the W/O/W multiple emulsions-based vaccine resulted in increased protection against tumor challenge compared to IFA-based vaccine (p < 0.05, n = 8) signifying induction of enhanced anti-tumor immunity. In addition, serum Th1 cytokine levels and immuno-histochemistry of excised tumor tissues indicated activation and local infiltration of antigen specific cytotoxic T-lymphocytes into and/or surrounding the tumor mass. Moreover, the newly developed vaccine formulation did not induce any overt systemic toxicity. CONCLUSION: Novel W/O/W multiple emulsions-based vaccine efficiently delivers the gp100 peptide antigen to induce cell-mediated anti-tumor immunity and offers an alternate, safe vaccine delivery system.

Phosphatidylinositol 3-kinase inhibitor (PIK75) containing surface functionalized nanoemulsion for enhanced drug delivery, cytotoxicity and pro-apoptotic activity in ovarian cancer cells.

PURPOSE: Ovarian cancer is a debilitating disease, which needs multi-pronged approach of targeted drug delivery and enhanced efficacy with the use of combination therapeutics. In this study, we have examined the anticancer activity of PIK75 incorporated in surface functionalized nanoemulsions for targeted delivery to SKOV-3 cells. A pro-apoptotic molecule C(6)-ceramide was also co-delivered to augment therapeutic efficacy. METHODS: EGFR and FR functionalized nanoemulsions incorporating PIK75 and C(6)-ceramide were characterized for particle size, surface charge, entrapment efficiency and morphology. Fluorescence and quantitative uptake studies were conducted in SKOV-3 cells to determine intracellular distribution. Cell viability was assessed using MTT assay while mechanism of cytotoxicity was evaluated using capsase-3/7, TUNEL and hROS assay. RESULTS: Cytotoxicity assay showed 57% decrease in IC(50) value of PIK75 following treatment with EGFR targeted nanoemulsion and 40% decrease following treatment with FR targeted nanoemulsion. Combination therapy with PIK75 and ceramide enhanced the cytotoxicity of PIK75 compared to therapy with individual formulations. The increase in cytotoxicity was attributed to increase in cellular apoptosis and hROS activity. CONCLUSION: The results of this study showed that the targeted system improved cytotoxicity of PIK75 compared to the non-targeted system. Combination therapy with ceramide augmented PIK75's therapeutic activity.

The antimicrobial activity of the appetite peptide hormone ghrelin.

The present study examined the antimicrobial activity of the peptide ghrelin. Both major forms of ghrelin, acylated ghrelin (AG) and desacylated ghrelin (DAG), demonstrated the same degree of bactericidal activity against Gram-negative Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa), while bactericidal effects against Gram-positive Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis) were minimal or absent, respectively. To elucidate the bactericidal mechanism of AG and DAG against bacteria, we monitored the effect of the cationic peptides on the zeta potential of E. coli. Our results show that AG and DAG similarly quenched the negative surface charge of E. coli, suggesting that ghrelin-mediated bactericidal effects are influenced by charge-dependent binding and not by acyl modification. Like most cationic antimicrobial peptides (CAMPs), we also found that the antibacterial activity of AG was attenuated in physiological NaCl concentration (150mM). Nonetheless, these findings indicate that both AG and DAG can act as CAMPs against Gram-negative bacteria.

Combinatorial-designed multifunctional polymeric nanosystems for tumor-targeted therapeutic delivery.

By definition, multifunctional nanosystems include several features within a single construct so that these devices can target tumors or other disease tissue, facilitate in vivo imaging, and deliver a therapeutic agent. Investigations of these nanosystems are rapidly progressing and provide new opportunities in the management of cancer. Tumor-targeted nanosystems are currently designed based primarily on the intrinsic physico-chemical properties of off-the-shelf polymers. Following fabrication, the surfaces of these nanoscale structures are functionalized for passive or active targeted delivery to the tumors. In this Account, we describe a novel approach for the construction of multifunctional polymeric nanosystems based on combinatorial design principles. Combinatorial approaches offer several advantages over conventional methods because they allow for the integration of multiple components with varied properties into a nanosystem via self-assembly or chemical conjugation. High-throughput synthesis and screening is required in polymer design because polymer composition directly affects properties including drug loading, retention in circulation, and targeting of the nanosystems. The first approach relies on the self-assembly of macromolecular building blocks with specific functionalities in aqueous media to yield a large variety of nanoparticle systems. These self-assembled nanosystems with diverse functionalities can then be rapidly screened in a high-throughput fashion for selection of ideal formulations, or hits, which are further evaluated for safety and efficacy. In another approach, a library of a large number of polymeric materials is synthesized using different monomers. Each of the formed polymers is screened for the selection of the best candidates for nanoparticle fabrication. The combinatorial design principles allow for the selection of those nanosystems with the most favorable properties based on the type of payload, route of administration, and the desired target for imaging and delivery.

Anti-angiogenic effects of betulinic acid administered in nanoemulsion formulation using chorioallantoic membrane assay.

Betulinic acid (3beta, hydroxy-lup-20(29)-en-28-oic acid, BA), a pentacyclic triterpenoid, is derived from a widely distributed natural anticancer compound betulin. It has selective anticancer activity against several tumor cells, and recently it was shown that it also possess anti-angiogenic effects. The objective of this study was to formulate betulinic acid, a poorly aqueous-soluble compound, in flax-seed oil containing nanoemulsion formulation for enhanced delivery efficiency and to effectively inhibit the tumor angiogenic process. The nanoemulsion was prepared using high pressure homogenization method with a Microfludizer processor. The betulinic acid nanoemulsion was studied for the effect on the angiogenic process by performing the in vivo chick embryo chorioallantoic membrane (CAM) assay. The sample volume of 1 microl and 5 microl of the blank and BA nanoemulsions were applied directly on the CAM. The preliminary results from macroscopic, morphological and immunohistochemical evaluations have shown that morphological change was produced in the CAM mesenchyme with a negative impact on the normal growth of the capillaries. Betulinic acid does possess anti-angiogenic activity in a dose dependent manner, and the nanoemulsion formulation maintained this effect.

Preliminary evaluation of a nanotechnology-based approach for the more effective diagnosis of colon cancers.

AIM: The goal of this research was to develop and preliminarily test a novel technology and instrumentation that could help to significantly increase the diagnostic yield of current colon cancer screening procedures. This technology is based on a combined fluorescence-optical coherence tomography (OCT) imaging, and topical delivery of a cancer-targeting agent. MATERIALS & METHODS: Gold colloid-adsorbed poly(ε-caprolactone) microparticles were labeled with a near-infrared dye, and functionalized with argentine-glycine-aspartic acid (RGD peptide) to effectively target cancer tissue, and enhance fluorescence-imaging contrast. The RGD peptide recognizes the α(v)ß(3)-integrin receptor, which is overexpressed by epithelial cancer cells. OCT was used under fluorescence guidance to visualize tissue morphology and, thus, to serve as a confirmatory tool for cancer presence. RESULTS: A preliminary testing of this technology on human colon cancer cell lines, a mouse model of colon cancer, as well as human colon tissue specimens, was performed. Strong binding of microparticles to cancer cells and no binding to cells that do not significantly express integrins, such as mouse fibroblasts, was observed. Preferential binding to cancer tissue was also observed. Strong fluorescence signals were obtained from cancer tissue, owing to the efficient binding of the contrast agent. OCT imaging was capable of revealing clear differences between normal and cancer tissue. CONCLUSION: A dual-modality imaging approach combined with topical delivery of a cancer-targeting contrast agent has been preliminarily tested for colon cancer diagnosis. Preferential binding of the contrast agent to cancer tissue allowed the cancer-suspicious locations to be highlighted and, thus, guided OCT imaging to visualize tissue morphology and determine tissue type. If successful, this multimodal approach might help to increase the sensitivity and the specificity of current colon cancer-screening procedures in the future.

A review of multifunctional nanoemulsion systems to overcome oral and CNS drug delivery barriers.

The oral and central nervous systems (CNS) present a unique set of barriers to the delivery of important diagnostic and therapeutic agents. Extensive research over the past few years has enabled a better understanding of these physical and biological barriers based on tight cellular junctions and expression of active transporters and metabolizing enzymes at the luminal surfaces of the gastrointestinal (GI) tract and the blood-brain barrier (BBB). This review focuses on the recent understanding of transport across the GI tract and BBB and the development of nanotechnology-based delivery strategies that can enhance bioavailability of drugs. Multifunctional lipid nanosystems, such as oil-in-water nanoemulsions, that integrate enhancement in permeability, tissue and cell targeting, imaging, and therapeutic functions are especially promising. Based on strategic choice of edible oils, surfactants and additional surface modifiers, and different types of payloads, rationale design of multifunctional nanoemulsions can serve as a safe and effective delivery vehicle across oral and CNS barriers.

Curcumin enhances oral bioavailability and anti-tumor therapeutic efficacy of paclitaxel upon administration in nanoemulsion formulation.

The aim of this study was to evaluate the effect of curcumin (CUR) in oral bioavailability and therapeutic efficacy of paclitaxel (PTX) administered in nanoemulsion to SKOV3 tumor-bearing nu/nu mice. Oral administration of the mice with CUR at 50 mg/kg for 3 consecutive days resulted in a down regulation of intestinal P-glycoprotein (Pgp) and cytochrome P450 3A2 (CYP3A2) protein levels. PTX, a Pgp and CYP3A2 substrate, was administered orally at 20 mg/kg in solution or nanoemulsion either as single agent or upon pretreatment with CUR at 50 mg/kg in tumor-bearing mice. Plasma AUC(0-∞) of PTX administered in nanoemulsion to CUR pretreated mice showed 4.1-fold increase relative to controls. Similarly, relative PTX bioavailability was increased by 5.2-fold, resulting in a 3.2-fold higher PTX accumulation in the tumor tissue. PTX administered in nanoemulsion to CUR pretreated mice also showed significantly enhanced anti-tumor activity. Preliminary safety evaluation showed that CUR + PTX combination did not induce any acute toxicity as measured by body weight changes, blood cell counts, liver enzyme levels, and liver histopathology. The results of this study suggest that combination of PTX and CUR, administered in nanoemulsions, could improve oral bioavailability and therapeutic efficacy in ovarian adenocarcinoma.

Targeting stents with local delivery of paclitaxel-loaded magnetic nanoparticles using uniform fields.

The use of stents for vascular disease has resulted in a paradigm shift with significant improvement in therapeutic outcomes. Polymer-coated drug-eluting stents (DES) have also significantly reduced the incidence of reobstruction post stenting, a disorder termed in-stent restenosis. However, the current DESs lack the capacity for adjustment of the drug dose and release kinetics to the disease status of the treated vessel. We hypothesized that these limitations can be addressed by a strategy combining magnetic targeting via a uniform field-induced magnetization effect and a biocompatible magnetic nanoparticle (MNP) formulation designed for efficient entrapment and delivery of paclitaxel (PTX). Magnetic treatment of cultured arterial smooth muscle cells with PTX-loaded MNPs caused significant cell growth inhibition, which was not observed under nonmagnetic conditions. In agreement with the results of mathematical modeling, significantly higher localization rates of locally delivered MNPs to stented arteries were achieved with uniform-field-controlled targeting compared to nonmagnetic controls in the rat carotid stenting model. The arterial tissue levels of stent-targeted MNPs remained 4- to 10-fold higher in magnetically treated animals vs. control over 5 days post delivery. The enhanced retention of MNPs at target sites due to the uniform field-induced magnetization effect resulted in a significant inhibition of in-stent restenosis with a relatively low dose of MNP-encapsulated PTX (7.5 microg PTX/stent). Thus, this study demonstrates the feasibility of site-specific drug delivery to implanted magnetizable stents by uniform field-controlled targeting of MNPs with efficacy for in-stent restenosis.

Pharmacokinetics and pharmacodynamics of chlorambucil delivered in long-circulating nanoemulsion.

Chlorambucil was incorporated into a nanoemulsion modified with poly(ethylene glycol) to improve its pharmacokinetics and tissue distribution, and thus enhance its therapeutic efficacy. A long-circulating nanoemulsion (LNE) was prepared using soybean oil, egg lecithin, cholesterol and PEG(2000)DSPE. The LNE had an oil droplet size <200 nm with a surface charge of -32.2 to -35.6 mV. Approximately, 97% of the chlorambucil was encapsulated in the LNE. Intravenous (i.v.) administration of the chlorambucil LNE to C57 B/6 mice showed improved pharmacokinetic parameters with 1.4-fold higher area under the plasma concentration-time curve (AUC) and 1.3-fold longer half-life compared to a non-PEG-modified nanoemulsion, and 2.7-fold higher AUC and 7.6-fold longer half-life compared to chlorambucil solution. Tissue distribution studies after i.v. administration with LNE showed a considerable decrease in drug uptake in the reticulo-endothelial system containing organs compared to non-PEG-modified nanoemulsion. Additionally, the chlorambucil delivered in LNE significantly enhanced therapeutic efficacy in the subcutaneous colon-38 adenocarcinoma tumor mouse model with no apparent increase in toxicity. This study suggests that LNE could produce remarkably improved pharmacokinetic profile and therapeutic efficacy of chlorambucil compared to non-PEG-modified nanoemulsion and solution.