Producing micron- and nano-size formulations for functional foods applications

Background: Nutrient deficiencies affect the health and wellness of large populations around the world. For example, the majority suffer from vitamin, essential fatty acid (such as omega-3), dietary fiber, and other important ingredient deficiencies due to their limited supply in the human food chain. Current trends in the nutraceutics industry to place these substances in higher. more-efficiently dispersed quantities in our food have become critically essential to their business plans. Nutrients in the form of small solids or droplets improve bioavailability. However, there remain numerous barriers to successful implementation of cost effective manufacturing processes. These challenges are addressed in the work presented here with particular focus on stability, bioavailability, and consumer acceptance. The goal is to develop large scale manufacturing systems that implement efficient platform technologies, with their respective operational maps, to produce functional food formulations, with particle sizes of these specially formulated nutraceutical ingredients in the micron-and nano- range.Objective: Demonstrating that stable micron- and nano-size emulsions, liposomes, and aqueous suspensions of functional food formulations can be produced using both “top down” and “bottom up” methods is our main objective. Addressing the challenges associated with the incorporation of these ingredients into large scale manufacturing systems, mainly mechanical stability and related shelf-life issues, is also a focus. That is, to develop proper processing protocols providing improved quality foods enriched with ingredients that are in limited supply in our food chain; to enhance human health and wellness world-wide.Methods: The formulations considered here typical of those used for increasing bioavailability of the infused, specially formulated ingredients with anti-cancer, anti-aging, and in-general wellness properties, lowering fat content and enhancing the shelf-life stability. Included are (a) an oil-in-water (fish oil/omega-3) emulsion, (b) liposome chaperones to vitamin C, and (c) aqueous suspensions (curcumin crystals, lutein/carotenoids, and fiber in soy milk). The production techniques include both “top-down” particle size reduction and “bottom-up” formation of crystals/precipitates via solubility adjustments. Both techniques are based on high shear processing of multiple liquid feeds. Using an impinging jet system, micro-mixing scales less than 100 nm were obtained.Results: (a) All nano-emulsion types, single, double and larger, either as oil-in-water and water-in-oil, can effectively be produced from various formulations using “top-down” methods. Illustrated here are single, oil-in-water systems; concentrations of 12-14 wt. % fish oil/omega-3 were mixed with water containing food grade surfactants. The high shear processing produced stable, submicron particles; with median particle sizes of 119-163 nm, no particles larger than 1 micron, and the “fish” odor was suppressed. Pertinent discussions related to the other types are also given as suggested path forward approaches for the development of nutrient enriched functional foods. This includes water-in-oil formulations for reduced fat content and the delivery of multiple species via double and triple emulsions, as compared to liposome configurations. (b) Although liposomes may be used to encapsulate both hydrophobic and hydrophilic substances, we selected liposomal vitamin C as our initial proof-of-concept system since it is absorbed into the body over four times more easily than its non-encapsulated form. After top down processing, the median size was 200 nm, compared to a median size of about 5 microns obtained by traditional self-assembly protocols. (b) Aqueous suspensions of micron- and nano- size formulations were also accomplished. The top down size reduction technique was used for processing soy bean fibers and lutein and the bottom-up method used for curcumin crystals. The fibers initially had a median size of 150 microns and a bi-modal distribution was obtained after processing; 99% of the particles were smaller than 15 microns with median sizes at 10 microns and the larger peak at about 200 nm. The curcumin submicron particles were formed via anti-solvent crystallization; with stable particles in the range of 300-500 nm.  Conclusions: Our study demonstrates that stable micron- and nano-size emulsions, liposomes, and aqueous suspensions can be produced using both “top down” and “bottom up” methods. The formulation properties, in terms of particle size and stability, strongly depend on the processing parameters used in terms of energy input and temperature history. The energy requirements of the “bottom up” methods may be substantially lower than those of “top down” methods. Although some of the processes presented here have been scaled up to commercial levels, more work is needed in terms of fully assessing the bioavailability of the produced formulations and optimizing the processes to minimize cost. Key words: nano-emulsion, nano-suspension, high-shear processing, crystallization, curcumin, fish oil, liposomal vitamins: C and E, lutein, nutraceuticals, omega-3, soybean fiber

Bottom up Nano-particle Formation via Controlled Crystallization and Chemical Reactions

Many manufacturing techniques to produce nano-materials via a “bottom-up” approach are currently being developed and evaluated. The PureNanoTM platform technology developed by Microfluidics International Corporation (MFIC) has proven to be both an effective and energy efficient method to produce nano-scale entities including emulsions in addition to suspensions. This nano-manufacturing platform utilizes crystallization, precipitation and chemical reaction methods that produce nano-particles with specified size distributions and a desired morphology. The solids formed can be either amorphous or crystalline, which may exist in numerous polymorphs. In many cases the ability to obtain a specific composition (single species or mixture) is possible via careful selection and implementation of key processing conditions. The methods are based on controlling the local degree of super-saturation (SS) and/or stoichiometry during their formation and subsequent configuration and growth, when appropriate. To accomplish this, operational strategies and innovative processing techniques are coupled with qualitative insight into the basic mechanisms involved with these processes. Validation of the technology at the bench scale for crystallization, emulsions/cargo loading, and multi-phase reactions (interfacial and homogeneous) provided the justification to develop commercial scale systems. Examples are given here for crystallization of drugs for the pharmaceutical industry, a catalyst formed by deposition of metallic crystals on a carbon substrate, production of fine chemicals via emulsion formation for multi-phase reactions, and a homogeneous substitution reaction forming an insoluble product. Nano-materials with median particle size as low as 50 nm were produced. With respect to the drug particles, they were highly crystalline, of a single polymorph and pure. In all cases, results indicate both process performance enhancement and product quality/functionality improvements compared to materials produced with conventional methods, with at least 1-2 order of magnitude increases in surface/interfacial area and reduced energy needs. Furthermore, the technology is suitable for current Good Manufacturing Practices (cGMP) manufacturing.

A nanoemulsion of an anti-oxidant synergy formulation reduces tumor growth rate in neuroblastoma-bearing nude mice

Neuroblastoma, the most common form of childhood cancer, may arise from a biochemical block of cellular differentiation and a resultant continuation of a proliferative state. Neuroblastoma often spontaneously reverts by undergoing partial differentiation and ultimate degeneration and may be associated with the generation of reactive oxygen species (ROS). We have recently reported in neuroblastoma cell culture studies that an anti-oxidant synergy formulation (ASF) can induce differentiation and buffer neuronal degeneration and oxidative stress in cultured cortical neurons and in central nervous system tissue of apolipoprotein E-deficient mice. The objective of the present study was to investigate whether a subcutaneous injection and/or transdermal application of a nanoemulsion preparation of ASF would reduce tumor growth rate in a neuroblastoma xenograph mouse model. The results indicate that whereas suspensions of ASF were ineffective in decreasing tumor growth rate in the neuroblastoma mouse model, tumor growth rate was similarly reduced an average 65% by either subcutaneous injection or transdermal application of an ASF nanoemulsion preparation to the tumor. In conclusion, the data suggest that subcutaneous and/or transdermal application of an ASF nanoemulsion preparation is effective in reducing tumor growth rate in this neuroblastoma mouse model.