Nanoemulsion-based Delivery System Research Articles

Surface Modified Carvacrol-rich Satureja khuzestanica Essential Oil Nanoemulsion: A Novel Paclitaxel Formulation Induced Apoptosis on Paclitaxel-Resistant Breast Cancer Cells

Background: The ability of cancer cells to develop multidrug resistance (MDR) is a major challenge in modern chemotherapy. The current generation of commercially available paclitaxel formulations have not been designed to treat resistant tumours. In this study, a nanoemulsion-based delivery system was developed to enhance the efficacy of paclitaxel against resistant breast cancer cells. Methods: The nanoemulsion was formulated using carvacrol-rich Satureja khuzestanica essential oil. Modification of nanoemulsion was performed by incorporating tocopheryl polyethylene glycol 1000 succinate (TPGS) which could inhibit drug resistance in cancer cells. Fabrication of paclitaxel nanoemulsion was performed by high speed homogenization. The cytotoxicity of prepared formulation against resistant breast cancer cells was investigated by MTT assay. Flow cytometry technique was used for cell cycle arrest analysis and examination of the apoptosis induction ability of prepared nanoemulsion. Results: The nanoemulsion had a relatively small mean droplet diameter (93.6 ± 4.2 nm) and good long-term stability. The ability of paclitaxel to inhibit P-gp function in paclitaxel-resistant breast cancer cells (MCF-7/PTX) was synergistically enhanced by administering it within the nanoemulsion. The cytotoxicity of the prepared nanoemulsion on the HUVEC normal cells was much lower than that of MCF-7/PTX cells. Cell cycle analysis utilizing flow cytometry showed that the paclitaxel-loaded nanoemulsion promoted G2-M arrest. Flow cytometry also demonstrated that this nanoemulsion induced apoptosis in MCF-7/PTX cells. Interestingly, apoptosis increased from 20.0% for the free paclitaxel treated group to 85.2 % for the paclitaxel-loaded nanoemulsion treated group. Conclusion: This novel paclitaxel nanoemulsion efficiently suppressed the drug resistance of breast cancer cells and induced effective apoptosis in very low concentrations of paclitaxel.

Fabrication and characterization of bioactive nanoemulsion-based delivery systems

In this work, a nanoemulsion-based delivery system was developed by encapsulation of different concentrations (0.50%, 0.75% and 1.00% v/v) of oregano essential oil (OEO) within poly(vinyl alcohol). The delivery systems (OEO-loaded nanoemulsion systems (NESs)) were characterized in terms of size distribution, zeta potential and thermal, molecular, microstructural and antifungal properties. The average droplet diameter values were determined to be within the range 70–75 nm, while zeta potential values within the range 3.13–19.90 mV were recorded. An increase in the OEO concentration did not affect the size distribution of nanoemulsions. Change in the concentrations showed no visible differences in Fourier transform infrared spectra. However, for concentrations of 0.50, 0.75 and 1.00%, endothermic peak temperatures were recorded as 94, 105 and 117°C, respectively. The antifungal activity of NESs against the mycelial growth of Aspergillus niger was evaluated, revealing a significant enhancement in the antifungal activity in comparison with that of free OEO. The zone diameter of mycelial growth could be reduced by around 20, 55 and 65% using NESs at levels of 0.50, 0.75 and 1.00% v/v, respectively, over 6 days of incubation. The results of this study revealed the stronger antifungal efficiency of OEO by its encapsulation into NESs as compared with that of free OEO.

Assessment of Fennel Oil Microfluidized Nanoemulsions Stabilization by Advanced Performance Xanthan Gum.

In this work, nanoemulsion-based delivery system was developed by encapsulation of fennel essential oil. A response surface methodology was used to study the influence of the processing conditions in order to obtain monomodal nanoemulsions of fennel essential oil using the microchannel homogenization technique. Results showed that it was possible to obtain nanoemulsions with very narrow monomodal distributions that were homogeneous over the whole observation period (three months) when the appropriate mechanical energy was supplied by microfluidization at 14 MPa and 12 passes. Once the optimal processing condition was established, nanoemulsions were formulated with advanced performance xanthan gum, which was used as both viscosity modifier and emulsion stabilizer. As a result, more desirable results with enhanced physical stability and rheological properties were obtained. From the study of mechanical spectra as a function of aging time, the stability of the nanoemulsions weak gels was confirmed. The mechanical spectra as a function of hydrocolloid concentration revealed that the rheological properties are marked by the biopolymer network and could be modulated depending on the amount of added gum. Therefore, this research supports the role of advanced performance xanthan gum as a stabilizer of microfluidized fennel oil-in-water nanoemulsions. In addition, the results of this research could be useful to design and formulate functional oil-in-water nanoemulsions with potential application in the food industry for the delivery of nutraceuticals and antimicrobials.

Anethum graveolens Essential Oil Encapsulation in Chitosan Nanomatrix: Investigations on In Vitro Release Behavior, Organoleptic Attributes, and Efficacy as Potential Delivery Vehicles Against Biodeterioration of Rice (Oryza sativa L.)

The study deals with first time report on encapsulation of chemically characterized Anethum graveolens essential oil within chitosan nanomatrix (Nm-AGEO) using ionic gelation technique to enhance the antimicrobial, antiaflatoxigenic, antioxidant, and in situ efficacy against stored rice biodeterioration. GC-MS analysis of AGEO revealed dill apiol (33.79%), carvone (27.19%), and limonene (13.76%) as major components. Nm-AGEO characterization through scanning electron microscopy (SEM), X-ray diffractometry (XRD), and Fourier transform infrared spectroscopy (FT-IR) confirmed successful encapsulation of AGEO within chitosan as an encapsulant. Biphasic and sustained release pattern reflected controlled volatilization of bioactives, helpful in shelf-life extension of stored food commodities. Nm-AGEO caused significant impairment in fungal ergosterol biosynthesis and enhanced leakage of vital ions indicating destabilization in plasma membrane integrity. Inhibition of methylglyoxal (aflatoxin inducer) biosynthesis by Nm-AGEO confirmed novel antiaflatoxigenic mechanism of action, suggesting its future exploitation for development of aflatoxin-resistant rice varieties through green transgenics. Nm-AGEO induced impairment in antioxidant defense enzymes (SOD, CAT) and non-enzymatic defense biomolecules GSH and GSSG revealing biochemical mechanism of action. In silico modeling of carvone and limonene with Omt-A and Ver-1 genes suggested molecular mechanism of aflatoxin inhibition. Treatment of rice samples with Nm-AGEO caused significant protection from aflatoxin B1 contamination and lipid peroxidation without altering organoleptic properties. Moreover, favorable safety profile for mammalian system and non-phytotoxic nature of chitosan-fabricated AGEO nanoemulsion-based delivery system recommend attention of food industries for its formulation as potential green preservative.

Co-Delivery of Imiquimod and Curcumin by Nanoemugel for Improved Topical Delivery and Reduced Psoriasis-Like Skin Lesions.

The current investigation aimed to improve the topical efficacy of imiquimod in combination with curcumin using the nanoemulsion-based delivery system through a combinatorial approach. Co-delivery of curcumin acts as an adjuvant therapeutic and to minimize the adverse skin reactions that are frequently associated with the topical therapy of imiquimod for the treatment of cutaneous infections and basal cell carcinomas. The low-energy emulsification method was used for the nano-encapsulation of imiquimod and curcumin in the nanodroplet oil phase, which was stabilized using Tween 20 in an aqueous dispersion system. The weak base property of imiquimod helped to increase its solubility in oleic acid compared with ethyl oleate, which indicates that fatty acids should be preferred as the oil phase for the design of imiquimod-loaded topical nanoemulsion compared with fatty acid esters. The phase diagram method was used to optimize the percentage composition of the nanoemulsion formulation. The mean droplet size of the optimized nanoemulsion was 76.93 nm, with a polydispersity index (PdI) value of 0.121 and zeta potential value of −20.5 mV. The optimized imiquimod-loaded nanoemulsion was uniformly dispersed in carbopol 934 hydrogel to develop into a nanoemulgel delivery system. The imiquimod nanoemulgel exhibited significant improvement (p < 0.05) in skin permeability and deposition profile after topical application. The in vivo effectiveness of the combination of imiquimod and curcumin nanoemulgel was compared to the imiquimod nanoemulgel and imiquimod gel formulation through topical application for ten days in BALB/c mice. The combination of curcumin with imiquimod in the nanoemulgel system prevented the appearance of psoriasis-like symptoms compared with the imiquimod nanoemulgel and imiquimod gel formulation entirely. Further, the imiquimod nanoemulgel as a mono-preparation slowed and reduced the psoriasis-like skin reaction when compared with the conventional imiquimod gel, and that was contributed to by the control release property of the nano-encapsulation approach.

A nanoemulsion-based delivery system for imatinib and in vitro anticancer efficacy

A self-nanoemulsifying drug delivery system (SNEDDS) composed of ethyl oleate, Tween 80 and polyethylene glycol 600 was prepared as a new route to improve the efficacy of imatinib. The drug-loaded SNEDDS formed nanodroplets of ethyl oleate stabilized by Tween 80 and polyethylene glycol 600 with a diameter of 81.0±9.5 nm. The nanoemulsion-based delivery system was stable for at least two months, with entrapment efficiency and loading capacity of 16.4±0.1 and 48.3±0.2%, respectively. Imatinib-loaded SNEDDS was evaluated for the drug release profiles, and its effectiveness against MCF-7 cell line was investigated. IC50 values for the imatinib-loaded SNEDDS and an imatinib aqueous solution were 3.1 and 6.5 µg mL-1, respectively.

Nanoemulsion-based delivery systems for testing nutraceutical efficacy using Caenorhabditis elegans: Demonstration of curcumin bioaccumulation and body-fat reduction

The genome of the nematode Caenorhabditis elegans shares many similarities with that of humans and so it is widely used as a model in pharmaceutical and nutritional studies. C. elegans has a small mouth and therefore very fine lipid particles are required to orally deliver hydrophobic nutraceuticals. In this study, a nanoemulsion-based delivery system was developed to deliver curcumin to C. elegans. Nanoemulsion were fabricated with different mean particle diameters (d32 = 150 nm and 300 nm), lipid types (Medium chain triglyceride, corn, and fish oil), and emulsifier types (Tween 80 and whey protein). The auto-fluorescence intensity of curcumin was used as an indicator of curcumin accumulation in C. elegans. The structure and composition of nanoemulsions had a significant influence on curcumin bioaccumulation in C. elegans. Curcumin bioaccumulation increased with increasing droplet size, was found to be higher in nanoemulsion containing corn oil compared with those containing fish oil or MCT, and was higher for droplets coated by whey protein than by Tween 80. The nematodes treated with curcumin-loaded nanoemulsions showed significantly reduced fat accumulation compared to the control group. This study could provide useful information to widen the application of C. elegans in research involving lipophilic compounds.

Development and Characterization of Green Tea Catechins and Ciprofloxacin-loaded Nanoemulsion for Intravaginal Delivery to Treat Urinary Tract Infection

The aim of the present study was to develop a nanoemulsion-based delivery system containing green tea catechins called polyphenon 60 and ciprofloxacin for intravaginal delivery to treat urinary tract infection. Polyphenon 60 and ciprofloxacin were encapsulated in a single nanoemulsion system prepared using ultrasonication technique. The nanoemulsion was characterized by determining particle size, zeta potential, morphological structure and estimating in vitro release and antibacterial efficacy. To determine the in vivo pharmacokinetic parameters and intravaginal transportation of nanoemulsion in Sprague Dawley rats, gamma scintigraphy and biodistribution study was conducted with technetium pertechnetate-labelled nanoemulsion. The preliminary antibacterial investigation showed synergy between these compounds with FICindex of 0.42. The developed formulation showed zeta potential of +55.3 mV and globule size of 151.7 nm, with polydispersity index of 0.196. The percent in vitro release for polyphenon 60 at the end of 7 h was 94.8±0.9, whereas for ciprofloxacin it was 75.1±0.15 in simulated vaginal media. Antibacterial activity evaluation against extended spectrum beta lactamase and metallo beta lactamase strains revealed that nanoemulsions containing 4 and 10 mg/ml each of polyphenon 60 and ciprofloxacin effectively inhibited the growth of bacterial strains. In biodistribution study, the percent radiolabelled drug per gram was found to be 3.50±0.26 and 3.81±0.30 in kidney and urinary bladder, respectively at 3 h. From these findings it could be concluded that the developed polyphenon 60+ciprofloxacin nanoemulsion showed antibacterial activity against Escherichia coli and was transported efficiently to the target organs through vaginal mucosa.

Nanoemulsion-based delivery system for enhanced oral bioavailability and Caco-2 cell monolayers permeability of berberine hydrochloride

Berberine hydrochloride (BBH) has a variety of pharmacological activities such as antitumor, antimicrobial, anti-inflammation, and reduce irritable bowel syndrome. However, poor stability and low oral bioavailability limited its usage. Herein, an oil-in-water nanoemulsion system of BBH was developed to improve its stability and oral bioavailability. The pseudoternary phase diagrams were constructed for the determination of composition of various nanoemulsions. The nanoemulsions of BBH composed of Labrafil M 1944 CS (oil phase), RH-40 (surfactant), glycerin (co-surfactant), and water (aqueous phase). The O/W nanoemulsion of BBH showed a relative bioavailability of 440.40% compared with unencapsulated BBH and was stable in our 6-month stability study. Further, there was a significant increase in intestinal permeability of BBH as assessed by Caco-2 cell monolayers and a significant reduction in efflux of BBH by the multidrug efflux pump P-glycoprotein. This study confirmed that the nanoemulsion formulation could be used as an alternative oral formulation of BBH to improve its stability, oral bioavailability and permeability.

Formulation and stability assessment of ergocalciferol loaded oil-in-water nanoemulsions: Insights of emulsifiers effect on stabilization mechanism

In the study, we investigated the effect of emulsifiers with different stabilizing mechanisms on the formulation and stability of ergocalciferol loaded oil-in-water (O/W) emulsions. O/W emulsion stabilized by modified lecithin (ML; electrostatic stabilization), sodium caseinate (SC; electrosteric stabilization) or decaglycerol monooleate (MO-7S; steric stabilization) were formulated using high-pressure homogenization. The Sauter mean diameter (d3,2) of emulsions produced by ML, SC and MO-7S were 126±1, 127±4 and 138±3nm, respectively. The stability of resulting emulsions was evaluated when they exposed to different environmental stresses and during 30days of storage at 25 and 55°C. Results showed that the emulsions prepared by MO-7S or ML were stable against a wide range of pH (2–8), while SC-stabilized emulsions showed instability with extensive droplet aggregation at pH4 or and 5. Only ML-stabilized emulsions showed droplet growth due to coalescence when treated at high NaCl concentration (300–500mM). In the absence of glucose, SC-stabilized O/W emulsions showed better freeze-thaw stability, in comparison to those formed with ML or MO-7S emulsifiers. The emulsion produced by ML was found to be stable to droplet aggregation at heating temperatures (80–120°C) for 1h. All the O/W emulsions stored at 25°C showed good physical and chemical stability. However, the chemical stability of ergocalciferol in emulsion system decreased in order of ML>MO-7S≫SC during storage at 55°C for a period of 30days. These findings provide valuable information for the development of nanoemulsion-based delivery system applied in food and beverage products.

Nanoemulsions in Cancer Therapy

Emulsions are two-phase mixtures of insoluble liquids in which a “continuous phase” surrounds discrete vesicles of the “dispersed phase”. Nanoemulsions or mini-emulsions or ultrafine emulsions or submicron emulsions are transparent or translucent oil-in-water (o/w) or water-in-oil droplets with a mean droplet diameter in the range between 100 and 500 nm. Nanoemulsion-based delivery system is superior to conventional topical dosage forms, such as ointment and gels, in several respects. Nanoemulsions are composed of safe, well-characterized ingredients, combined in a proprietary manner to yield stable emulsion. Cancer is a class of disorders characterized by abnormal growth of cells proliferating in an uncontrolled way.The efficiency of anticancer drugs is limited by their unsatisfactory properties, such as poor solubility, narrow therapeutic window, and intensive cytotoxicity to normal tissues, which may be the causes of treatment failure in cancer. Nanoemulsions increase the solubility of drugs exhibiting poor water solubility through entrapment in the core of the nanoemulsion droplets. © 2011 IGJPS. All rights reserved.