Methods of production of arginine-silicate complexes

Abstract

Methods of manufacturing inositol-stabilized arginine-silicate (“ASI”) complexes with reduced or eliminated clumping and with increased solubility.

Description

FIELD OF THE INVENTION

The present invention relates to a new process for the production of an arginine-silicate complex.

BACKGROUND OF THE INVENTION

Methods of producing arginine-silicate complexes (ASI) are taught in U.S. Pat. No. 6,803,456, which is incorporated herein in its entirety. The dietary supplement NITROSIGINE is a patented source of inositol-stabilized arginine silicate (ASI). Pre-clinical studies of ASI demonstrated superiority of this dietary ingredient over arginine in blood flow markers and have been shown to positively affect silicon absorption. The dietary supplement provides evidence of health benefits.

One problem with the current manufacturing and use of bulk ASI powder is that the ASI can clump. Some of the production lots tend to clump more quickly than other lots and to different degrees. Particle samples of various lots were evaluated during the manufacturing process. The results revealed that particles were present in various shapes and circumferences, with some degree of fractured or partial particles. There was no uniformity of shape and circumference. Because there is a lack of consistency in the particles and powder make up, and because there are clumping and solubility issues, there is a need for new and/or improved methods of manufacture to reduce and/or eliminate the clumping issue and to increase the solubility of the final product. The present invention provides methods for manufacturing that produces a particle size distribution to reduce and/or eliminate the clumping issue and increases the solubility of the ASI complex.

SUMMARY OF THE INVENTION

The present invention provides methods of producing ASI products and ASI complexes with reduced clumping or absence of clumping and increased solubility as compared to known methods. In certain embodiments, the methods reduce or eliminate clumping by producing specific particle or sphere size distributions. In other embodiments, an ASI product or ASI complex is provided with reduced clumping or no clumping, and increased solubility. In certain embodiments, an ASI complex is provided for inclusion in liquids, wherein the ASI complex has reduced or eliminated clumping characteristics, and increased solubility. Some embodiments provide nutritional and/or food beverages with ASI complexes with reduced or eliminated clumping characteristics, and increased solubility. In yet another embodiment, the methods reduce or eliminate clumping, increasing solubility by producing multiple particle size distribution more sphere sizes and particle shapes. In certain other embodiments, the present invention provides methods of reducing or eliminating clumping by producing particle spheres with reduced amounts of broken spheres or with the elimination of broken spheres.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a low magnification (Micron Bar=10×5 μm=50 μm) image illustrating typical structures present in a sample batch of a known ASI product.

FIG. 2 is a higher magnification (Micron Bar=10×4 μm=40 μm) image illustrating how the particles of a known ASI product aggregate together.

FIG. 3 is an image (Micron Bar=10×5.0 μm=50 μm) illustrating how particles of a known ASI product have broken apart, resulting in several pieces, and wherein the particle had a hollow interior.

FIG. 4 is an image (Micron Bar=10×3 μm=30 μm) illustrating a particle of a known ASI product breaking into smaller fragments, which shows the hollow interior.

FIG. 5 provides a high magnification image (Micron Bar=10×200 nm=2 μm) illustrating one of the typical, intact structures found in a sample batch.

FIG. 6 provides an image (Micron Bar=10×10 μm=100 μm) illustrating assorted structures typical within a sample batch.

FIG. 7 provides an image (Micron Bar=10×5.0 μm=50 urn) illustrating variation in structural size and presence of aggregation.

FIG. 8 provides an image (Micron Bar=10×4 μm=40 urn) illustrating particles that broke apart into multiple pieces, and showing hollow interiors.

FIG. 9 provides an image (Micron Bar=10×1 μm=10 urn) illustrating a particle split in two, with a thicker inner layer and a hollow center.

FIG. 10 provides an image (Micron Bar=10×200 nm=2 μm) illustrating variation in the manufactured/processed structural size of a sample batch.

FIG. 11 is a chart illustrating a particle size distribution of an ASI product of the invention compared to a known ASI product.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a process of making inositol-stabilized arginine-silicate complexes. Known methods of producing ASI are found in U.S. Pat. No. 6,803,456, which is incorporated herein in its entirety. The present invention provides steps to improve those methods by modifying the process to reduce unwanted clumping of the resulting ASI product.

As described in the patented process in U.S. Pat. No. 6,803,456, arginine is combined with a silicate salt and inositol at elevated temperature to form a suspension or solution, which, if not in solution, is heated to result in solution. The initial mixing temperature is preferably at least about 30° C., more preferably at least about 40° C., still more preferably at least about 50° C., even more preferably at least about 60° C. The initial mixing temperature can be chosen to balance energy costs and safety (keeping the temperature as low as possible) and speed of dissolution (raising the temperature as high as practical). Whether or not the initial mixture is a suspension or solution and regardless of the initial mixing temperature, the mixture is to be heated to about at least 80° C., preferably to about at least 90° C., more preferably to about 95° C. to assure proper formation of the desired complex solution prior to the spray drying step. Preferably, once raised to the at least 80° C. temperature, the material (solution/suspension) should be maintained at this temperature for at least about 4 minutes, more preferably for at least about 4.5 minutes, still more preferably at least about 5 minutes. The solution temperature can then be reduced as long as gel formation and crystallization do not take place, and the complex is maintained in solution. Generally, the temperature should not be reduced below about 55° C. in order to maintain the complex in solution before it is spray dried. However, if the solution is allowed to cool below this temperature and the product begins to show some precipitation, heating to above about 55° C. before spray drying usually brings the precipitate back into solution so that the solution can then be spray dried. In general, the spray drying can take place close to the time of dissolution and raising the temperature to the at least 80° C. temperature, so that little or no appreciable cooling takes place.

Once the arginine-silicate-inositol complex has been formed and is in solution, the solution is introduced into a spray drier. Any spray drying apparatus may be used, but a conical or flat bottom spray drier is preferred.

Because the primary use of the product is for a pharmaceutical or nutritional supplement purpose, pharmaceutically acceptable silicate salts are preferred. Preferably, the silicate salt is potassium silicate, although any other silicate salt that is acceptable for the end use is also suitable. Sodium silicate and magnesium silicate are particularly suitable alternatives, although other suitable silicates will be apparent to those of ordinary skill in this field. Preferably, the silicate has a low iron and/or low copper content so that the final arginine-silicate-polyol complex has a copper content of preferably 0 to not greater than about 50 ppm, more preferably 0 to not greater than about 40 ppm, still more preferably 0 to about 30 ppm, even more preferably 0 to not greater than about 20 ppm, most preferably 0 to not greater than about 10 ppm; and/or an iron content of preferably 0 to not greater than about 100 ppm, more preferably 0 to not greater than about 75 ppm, still more preferably 0 to about 50 ppm, even more preferably 0 to about 40 ppm, most preferably 0 to not greater than about 10 ppm. In addition, preferably the total heavy metal content of the complex should be 0 to not greater than about 20 ppm in order meet the current FDA maximum heavy metal content requirements. Generally commercially available electronic grade silicate material will meet the iron, copper, and heavy metal content requirements above. Furthermore, where the silicate is not a sodium silicate, the sodium content of the final arginine-silicate-polyol complex is preferably 0 to not greater than about 500 ppm, more preferably 0 to not greater than about 400 ppm, even more preferably 0 to not greater than about 350 ppm, most preferably 0 to not greater than about 320 ppm.

The complexes prepared in U.S. Pat. No. 6,803,456 employ inositol. Inositol is the most preferred material for the complex so that the most preferred complex for the invention is the arginine-silicate-inositol. For the remainder of this disclosure, reference to the “complex” without qualification means arginine-silicate-inositol complex, unless the context dictates otherwise.

In general, the molar ratio of arginine to silicate is about 0.5:1 to about 2:1, preferably about 0.75:1 to about 1.25:1, more preferably about 0.8:1 to about 1.2:1. Particularly suitable ratios of arginine:silicate include, among others, 1:1, 0.97:1, and 0.933:1. These ratios can be adjusted in the methods disclosed herein to reduce or eliminate the clumping and increase solubility of the produced ASI.

The molar ratio of the arginine to polyol (e.g., inositol) is typically in the range of about 1:1 to about 4:1, preferably about 1.25:1 to about 3:1, more preferably about 1.5:1 to about 3:1. Particularly suitable ratios include, without limitation about 3.25:about 1; about 3:about 1; about 2:about 1; about 1.75:about 1; and about 1.5:about 1. These ratios can be adjusted in the methods disclosed herein to reduce or eliminate unwanted clumping and increase solubility of the produced ASI.

The mixture resulting from the combination of inositol, silicate salt and arginine is a highly viscous suspension/solution, which is clarified by heating. In a preferred embodiment, the suspension/solution is heated to between about 80° C. and about 100° C., more preferably about 95° C., until clarification is observed. These temperatures can be increased or decreased as necessary in the methods disclosed herein to reduce or eliminate the unwanted clumping and increase solubility of the produced ASI.

Generally this requires at least about 4.5 minutes, preferably at least about 5 minutes of maintaining the temperature above the “between about 80° C. and about 100° C.” range. At this time, heating and stirring is discontinued. The solution is then introduced into a spray drier to obtain suitable product. The time for heating and stirring may be adjusted, as determined, to avoid the unwanted clumping of the resulting ASI. Further, the methods of the present invention provides for adjustments to temperatures, and to rotary and nozzle atomization to obtain the desired size and concentrations/percentages of particle sizes.

While it is believed that crystallization and gel formation are to be avoided, this can be determined as it relates to low solubility and the unwanted clumping does not occur. In those instances where immediate introduction into a spray drier is not possible, the clarified solution should be maintained at a sufficiently high temperature so as to avoid gel formation and crystallization. However, if some crystallization does occur, reheating to at least about 55° C. should re-dissolve the crystals and the product may then be introduced into the spray drier. As can be determined, any reheating steps addressing crystallization may be eliminated to avoid potential issues with broken or misshapen particles of ASI (e.g., spheres) that might lead to clumping.

Other means of dispensing the resulting ASI can be employed as necessary to avoid the unwanted clumping of the resulting ASI particles (e.g., spheres). Also, those means of dispensing the resulting ASI can include such means that permit desired particle size distributions, a more preferred particle shape, less broken particles (e.g., broken spheres), and/or combination thereof. This can involve inter alia using varied conical diameters for the spray drying steps, or such methods utilized in micronization to better control particle sizes to be within a preferred range of average diameter/sizes of the particles, which might reduce or eliminate the unwanted clumping and increase solubility of the ASI.

When addressing ASI particles, the different particle morphologies can be addressed and tested to determine the best ratios of the differing aspects of particle morphologies. Particle morphology can be described in terms of particle size, shape, internal structure, densities, and surface properties. As used herein, the different morphologies to be addressed and tested for reducing or eliminating unwanted clumping are discussed as relevant to that particular section of this disclosure.

To reduce or eliminate unwanted clumping and increase solubility, the method steps provided herein are modified to produce desired particle (e.g., sphere) sizes and particle size distributions. As a result of the modifications, particle sizes can be within an average size range of 1 to 50 μm of each other; preferably within 1 to 40 μm; more preferably 1 to 30 μm; even more preferably 1 to 20 μm; and most preferably 1 to 10 μm or 1 to 5 μm of each other.

In another method of the present invention, manufacturing steps can be performed and modified as necessary to achieve a preferred mixture of ASI particle shapes (e.g., spheres) to reduce or eliminate the unwanted clumping and increase solubility. The impact of different morphologies on unwanted clumping and solubility can be determined. That data can then be used to modify the method steps as necessary to produce varying ranges of morphologies relating to the level of one shape compared to other shapes. As necessary, the ratios of the various morphologies can be adjusted to produce the best desired ratio to reduce or eliminate the unwanted clumping and to increase the solubility. Such modifications or additional steps might involve tuning colloidal interactions in the suspensions. From these steps, a model can be developed to relate colloidal interaction potential to critical pressure exerted by solvent(s) in the flow. This can allow a more predictive particle shape.

In another method of the present invention, the impact of the presence and levels of incomplete particles will be determined. As used herein, incomplete particles includes, without limitations, incomplete complexes, broken particles, shattered or broken spheres, and combinations thereof. With the determination of the impacts of the incomplete particles on the clumping effect, modifications or additional steps will be taken to reduce or eliminate the impact on the clumping and increase solubility in the final product.

As shown herein, known methods of ASI production can lead to unwanted clumping and lowered solubility in the final product. Shown in FIGS. 1-10 are some examples of the unwanted clumping and other characteristics of a known ASI product. Each example used product samples that were sprinkled on an adhesive carbon tab attached to an SEM stub. Excess material was removed using a blast of air prior to gold and platinum/palladium coating.

FIG. 1 illustrates typical structures present in the known sample batch. FIG. 2 illustrates how the particles aggregate together. FIGS. 3-4 and 7-9 illustrate how broken and fragmented particles with hollow interiors. FIGS. 5-6 provide aspects of typical, intact structures found in a sample batch. FIG. 10 illustrates the variation in the manufactured/processed structural size of a sample batch of a known ASI product.

To avoid unwanted variations that can lead to increased clumping and lowered solubility, the methods of making inositol-stabilized arginine-silicate complexes of the present invention utilizes steps that alter and/or guide formation of the ASI complexes in a way that appropriately addresses the sphere shape differences, particle size differences, shattering or breaking up of particles, particle densities related to the interior space or structure, or combinations thereof.

In the manufacture of the product resulting from the methods provided herein, steps are performed to provide a particle size distribution, which results in a combination of increased solubility and reduced clumping.

During various attempts to solve known obstacles to overcoming ASI clumping and lowered solubility, a product with very small particles was made; however, the product clumped very quickly when exposed to air. Thus, production of an ASI product comprising a fine powder did not overcome the clumping or low solubility issues with the products from known methods. Similarly, when a product of larger, coarser particles was made and tested, it was found that these coarser particle products suffered the same clumping and low solubility issues.

Based on these issues, method steps were taken to produce particle size distributions that reduced clumping and enhanced solubility over the known products. The present invention provides for sphere size range(s) or particle size distributions that significantly improve solubility and reduce clumping. FIG. 11 is a graph demonstrating the distribution of particle sizes of a known ASI complex product (dashed line) compared to a product of the instant invention (solid line).

The following table is a further comparison of the known ASI product to that of a product of the instant invention. This table provides a side-by-side comparison of the importance of selecting an adequate particle size distribution. It was unexpected that, as seen in the above-chart and the table below, the products of the instant invention would result in improved solubility and reduced or eliminated clumping characteristics. Specifically, products within the particle size distributions of the instant invention resulted in clearer appearance when added to water; and there was no clumping or there was significantly reduced clumping.

	Percent Below Size
	Improved	Original
Size (uM)	Product	Product
250	100	97
180	100	93
125	98	59
106	88	44
90	81
75	67
63	44

As discussed herein, it was believed that reducing the average particle size so that all particles were a fine powder, e.g., 100% of particles were less than 74 μm; however, this approach resulted in near immediate clumping upon exposure to air, despite having a slight improvement in solubility. Attempts to approach a solution to the problems through increasing the average particle size above a certain level resulted in heavy clumping and sinking without dissolution. For these reasons, methods were developed to approach the ASI solubility and clumping problems from both directions.

As seen in the above table and in FIG. 11, superior results in reducing clumping and increasing solubility were achieved through an unexpected mixture of particle size distributions. These product characteristics are shown in the above table and in FIG. 11, wherein the particle size distribution of a product of this invention is compared to the particle distribution of the product of methods known in the art.

A preferred particle size distribution of the ASI composition of the present invention includes a mixture of particles comprising approximately 67% of particles with sizes between about 0.1 μm and about 75 μm, and approximately 33% of particles sizes between about 76 μm and about 200 μm. In another particle size distribution, the ASI composition comprises at least 50% of particles with sizes between about 0.1 μm and about 75 μm, and approximately 50% between about 76 μm and about 200 μm. While these are some of the preferred embodiments of products from the methods provided herein, it was found that differing levels of reduced clumping and increased solubility is achievable through the data presented in the chart and table provided herein. In one aspect, 98% of the particles of a product of the invention passed through a 125 micron mesh size, meaning that 98% of the particles were of both size and shape to pass through the mesh, as opposed to only 59% of the known ASI product.

These unexpected and surprising results address the clumping and low solubility issues associated with the known ASI products and the methods of producing the same. With these problems addressed, the ASI complexes of the methods of the instant invention have a better shipping and storing stability by avoiding the clumping issues known to occur. As with the clumping reduced or eliminated, solubility of the ASI complexes is also addressed. With the increased solubility, the ASI products are more operable and preferable for use in nutritional beverages, dietary supplement beverages and other liquid forms to be used in the market place. Thus, the unexpected reduction in clumping and the increased solubility changes the operability of ASI complexes in the market place over the known ASI-related products.

As will be appreciated, the methods, and the modifications and additions to the methods discussed herein, are to improve the manufactured ASI product. As will also be appreciated, the methods disclosed herein may be performed in whole or in part to address different morphology issues related to the particles that impact the unwanted clumping of the manufactured ASI product. It is expected that there will be modifications and additions that are within the spirit of the present disclosure.

Claims

1. A method of manufacturing an inositol-stabilized arginine-silicate (“ASI”) complex with reduced clumping and increased solubility, wherein the method comprises: combining arginine with a silicate salt and inositol;heating the combined arginine, silicate salt, and inositol mixture;mixing the arginine, silicate salt, and inositol mixture at temperature of at least about 30° C.;after mixing, heating the mixture to a temperature of at least about 80° C. whereby this temperature is maintained for at least about 4 minutes;cooling the mixture to a temperature of no less than about 55° C.;spray drying the mixture at a temperature of at least about 80° C.; andfurther comprising the step of tuning colloidal interactions in the mixture to produce an ASI product having particle size distribution as follows: 98% of the particles are of a size and shape to pass through a 125 micron mesh size and approximately 67% of particles are of sizes between about 0.1 μm and about 75 μm, and approximately 33% of particles are of sizes between about 76 μm and about 200 μm.

2. The method of claim 1, further comprising adjusting a synthesis temperature or temperatures, and making adjustments to a rotary or nozzle atomizer to obtain the particle size distribution.

3. The method of claim 1, wherein the spray drying is micronization.

4. The ASI complex of claim 1 comprising at least 50% of particles with sizes between about 0.1 μm and about 75 μm, and approximately 50% between about 76 μm and about 200 μm.

5. A beverage comprising an inositol-stabilized arginine-silicate (“ASI”) complex, wherein the ASI complex has a particle size distribution wherein 98% of the particles are of a size and shape to pass through a 125 micron mesh size, wherein the ASI complex has increased solubility and reduced clumping.

6. The beverage of claim 5, wherein the beverage is a nutritional beverage or a sport beverage.

7. The beverage of claim 5, wherein the ASI complex comprises a mixture of particles wherein approximately 67% of particles are of sizes between about 0.1 μm and about 75 μm, and approximately 33% of particles are of sizes between about 76 μm and about 200 μm.

8. The beverage of claim 5, wherein the ASI complex comprises at least 50% of particles with sizes between about 0.1 μm and about 75 μm, and approximately 50% between about 76 μm and about 200 μm.