U.S. patent application number 12/290575 was filed with the patent office on 2009-12-10 for method for producing flavored particulate solid dispersions.
Invention is credited to Paolo Blasl, Patrick P. DeLuca, David Johnson, David R. Worthen.
Application Number | 20090301504 12/290575 |
Document ID | / |
Family ID | 40591384 |
Filed Date | 2009-12-10 |
United States Patent
Application |
20090301504 |
Kind Code |
A1 |
Worthen; David R. ; et
al. |
December 10, 2009 |
Method for producing flavored particulate solid dispersions
Abstract
A method for producing flavoring materials consisting of a
flavor and a simple matrix material that are GRAS or approved for
use in food, and that will be stable under extremely adverse
conditions, greater than 50% moisture, high pH, high temperature
stability (60.degree. C.), yet be released in the oral cavity;
without the use of organic solvents, and with the use of
inexpensive materials and unsophisticated equipment.
Inventors: |
Worthen; David R.;
(Lexington, KY) ; Johnson; David; (Owensboro,
KY) ; DeLuca; Patrick P.; (Lexington, KY) ;
Blasl; Paolo; (Belmonte Picano, IT) |
Correspondence
Address: |
KRIEG DEVAULT LLP
ONE INDIANA SQUARE, SUITE 2800
INDIANAPOLIS
IN
46204-2079
US
|
Family ID: |
40591384 |
Appl. No.: |
12/290575 |
Filed: |
October 31, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61001225 |
Oct 31, 2007 |
|
|
|
Current U.S.
Class: |
131/274 |
Current CPC
Class: |
A23L 27/79 20160801;
A24B 15/283 20130101; A24B 13/00 20130101; A23L 27/74 20160801;
A23L 27/70 20160801 |
Class at
Publication: |
131/274 |
International
Class: |
A24B 15/00 20060101
A24B015/00 |
Claims
1. A method of producing edible flavored particulate solid
dispersions, comprising the steps of melting an edible matrix
material and homogenously incorporating therein one or more edible
flavoring agents, cooling the flavored melted matrix material to
achieve a solid dispersion having a flavor within an edible matrix,
and grinding the solid dispersion into particles and sieving the
resulting particles to achieve edible flavored particulate solid
dispersions of a desired size.
2. A method of producing edible flavored particulate solid
dispersions, comprising the steps of melting an edible matrix
material and homogenously incorporating therein one or more edible
flavoring agents, cooling the flavored melted matrix material to
achieve a solid dispersion having a flavor within an edible matrix,
and cutting or pressing one or more punches from the solid
dispersion to achieve edible flavored particulate solid dispersions
in the form of punches of a desired size.
3. A method of producing edible flavored particulate solid
dispersions, comprising the steps of melting an edible matrix
material and homogeneously incorporating therein one or more
flavoring agents, mixing with high shear the flavored melted matrix
material with an aqueous solution to create an agitated aqueous
dispersion, and cooling the agitated aqueous dispersion to a
temperature below the melting point of the flavored matrix material
to produce edible flavored particulate solid dispersions having a
flavor within an edible matrix that are recoverable by filtration,
flotation, centrifugation or vibro-separation.
4. The method according to claims 1, 2 or 3, wherein the matrix
material is selected from the group consisting of a wax, a fat, a
fatty alcohol, a sterol, cetyl alcohol, stearyl alcohol, paraffin,
polyethylene glycol, a fatty acid, a polyunsaturated fatty acid,
rudua fatty acid ester, palmitic acid, stearic acid, oleic acid,
lauric acid, myristic acid, behenic acid, a triglyceride,
polyethylene glycol, cholesterol, lecithin, a phospholipid, and
mixtures thereof.
5. The method according to claims 1, 2 or 3, wherein the flavoring
agent is selected from the group consisting of a volatile oil, an
essential oil, a botanical extract, methyl salicylate, ethyl
salicylate, cinnamic acid, cinnamon oil, peppermint oil, spearmint
oil, wintergreen oil, acetaldehyde, acetoin, aconitic acid,
anethole, benzaldehyde, N-butyric acid, d- or l-carvone,
cinnamaldehyde, citral, decanal, diacetyl, ethyl acetate, ethyl
butyrate, ethyl vanillin, eugenol, geraniol, geranyl acetate,
glycerol tributyrate, limonene, linalool, linalyl acetate, 1-malic
acid, methyl anthranilate, 3-methyl-3-phenyl glycidic acid ethyl
ester, piperonal, vanillin, citrus flavoring, berry flavoring, and
mixtures thereof
6. The method according to claim 1, wherein the grinding step
includes grinding in a blender, or oscillator, or mill, or grinder,
without freezing the flavored solid dispersion.
7. The method according to claim 3, wherein the aqueous solution
contains a surfactant selected from the group consisting of an
alcohol, a fatty alcohol, a fatty acid, a fatty acid ester,
polyvinyl alcohol, polyethylene glycol, alginic acid, a
phospholipid, lecithin, cholic acid, desoxycholic acid, diacetyl
tartaric acid esters of mono- and diglycerides, glycocholic acid,
mono- and diglycerides and their monosodium phosphate derivatives,
propylene glycol, ox bile extract, taurocholic acid, gum arabic,
agar-agar, ammonium alginate, calcium alginate, carob bean gum,
chondrus extract, ghatti gum, guar gum, potassium alginate, sodium
alginate, sterculia gum, tragacanth, hydroxypropylmethylcellulose,
any other water soluble derivatives of cellulose, and mixtures
thereof.
8. The method according to claim 7, wherein the concentration of
the surfactant ranges from about 0.1 percent to about 30% weight to
volume.
9. The method according to claim 3, wherein the mixing with high
shear is accomplished by stirring, blending, paddles, propellers,
impellers, or gas agitation using air, nitrogen, argon, helium, or
another suitable gases, or by combinations thereof.
10. The method according to claims 1, 2 or 3, wherein the flavored
particulate solid dispersions have a particle or punch size in the
range of about 10 nm to about 300 microns in diameter.
11. The method of claim 10, wherein the flavored particular solid
dispersions contain from about 1 to about 80% weight in weight
flavoring agents within the edible matrix.
12. The method according to claims 1, 2 or 3, and further
comprising the step of adding one or more colorants to the flavored
particulate solid dispersions prior to formation, during formation,
or after formation to impart thereto a desired coloration.
13. The method according to claims 1, 2 or 3 and further comprising
the step of dispersing the flavored particulate solid dispersions
within a consumer product selected from the group consisting of
tobacco, moist snuff, dry snuff, individually wrapped snuff
pouches, snuff pouch paper, edible films, coffee, tea, chewing gum,
confections, candy, or other food products.
14. A flavored particulate solid dispersion produced by the method
of claims 1, 2 or 3.
Description
[0001] This application claims the benefit of the filing date of
U.S. Provisional Patent Application Ser. No. 61/001,225, filed Oct.
31, 2007, pursuant to 35 U.S.C. .sctn. 120.
FIELD OF THE INVENTION
[0002] The present invention relates to particulate
flavored-material and more particularly to particulate flavored
materials comprising a flavor dispersed in or otherwise entrapped
within an edible matrix that can be used to release favors and
aromas in a controlled manner in consumer products, including
tobacco, and methods for preparing and using the same.
BACKGROUND OF THE INVENTION
[0003] Flavor encapsulation is employed to protect flavors from
degradation, to produce flavoring materials that may be dispersed
in bulk commodities, and to produce flavoring materials with
modified release characteristics. Volatile oils, perfumes, food
extracts and other flavor modifiers have been successfully
encapsulated and employed in a variety of consumer products. Flavor
encapsulation has been achieved using a number of technologies,
including spray drying, pan coating, spray coating, fluidized beds,
chemical encapsulation and comminution. Particulate flavor
composites may consist of shell-core constructs, multi-lamellar
vesicles, or as dispersions of flavor molecules or droplets in a
matrix, as well as other types of particles. Other methods include
molecular inclusion in cyclodextrin, granulation and coacervation.
A variety of materials are employed to encapsulate flavors,
including gelatin, mixed lipids and sweeteners (U.S. Pat. No.
4,803,082), polymerized acrylic materials (U.S. Pat. No. 3,520,949)
and starches.
[0004] Many compositions have been proposed for use as flavoring
materials, and methods have been disclosed for the production of
flavor and other core material encapsulation. Both hydrophilic and
hydrophobic compositions have been reported. Sorbitol, mannitol,
saccharin, sugar and starch hydrolysate, maltose, malto-dextrin,
corn syrup solids, maltose syrup solids, high fructose corn syrup
solids, starches, hydrocolloids, gums, proteins, partially
hydrolyzed proteins, modified proteins, modified hydrocolloids,
modified celluloses, gelatinized cereal solids, whey proteins and
alginates are examples of the hydrophilic materials that have been
proposed as coating materials in the prior art. On the other hand,
paraffin, triglycerides, fatty acids, fatty alcohols, waxes have
been proposed as hydrophobic encapsulating materials. Some of the
aforementioned materials have been proposed, and in some cases they
are currently used in pharmaceutical formulation to obtain active
controlled release.
[0005] U.S. Pat. No. 4,388,328 illustrates a flavor composite that
contains sorbitol, mannitol, saccharin, and a flavor material that
may be prepared in the form of sugar-free candies, or may be
reduced to particles or beads. The procedure consists of preparing
a eutectic mixture heating the mixture of the components to a
temperature of about 200 degrees C. and than cooling the same to 70
degrees C. Obviously, the high temperature employed may adversely
affect flavor stability, volatilization and encapsulation
efficiency.
[0006] In U.S. Pat. No. 4,610,890, a solid essential oil flavor
composition involving preparation of a heated or cooked aqueous
mixture of a sugar and starch hydrolysate, together with an
emulsifier, is claimed. In this reference the selected essential
oil is combined and blended with a mixture in a closed vessel under
controlled pressure conditions to form a homogeneous melt, the melt
being extruded into a relatively cool solvent, dried and combined
with a selected anti-caking agent to produce the stable, relatively
non-hygroscopic particulate flavor composition of the invention.
The temperature for the process is preferably maintained at or
below a maximum of about 126 degrees C.
[0007] In a family of U.S. patents, including U.S. Pat. Nos.
5,601,865; 5,792,505 and 5,958,502, what has been claimed is the
use of different materials, such as maltodextrins, corn syrup
solids, maltose syrup solids, high fructose corn syrup solids,
starches, hydrocolloids, gums, proteins, partially hydrolyzed
proteins, modified proteins, modified hydrocolloids, and modified
celluloses, to obtain a liquid melt, heating and mixing a matrix
and a volatile component, to solidify thereafter under a pressure
sufficient to prevent substantial volatilization of said volatile
component. In this invention, the dense amorphous, essentially
non-crystalline solid encapsulant may be described in many cases,
but not exclusively by those knowledgeable in the art as a `glass`
as characterized by a glass transition temperature.
[0008] British Patent 767,700 illustrates a method for making
particles comprising inclusions containing a fat-insoluble vehicle
carrying fat-soluble vitamins encased in a moisture-resistant
substance in which the fat insoluble vehicle is insoluble.
[0009] U.S. Pat. No. 3,186,909 conveys a method for melting a
composition containing fatty alcohol esters derived from sperm
whale oil, adding urea to the composition and dissolving the urea,
and adding fish liver oil and vitamins, thereby giving rise to a
homogeneous mixture which might be useful for making particles.
[0010] The use of the spray-drying technique is claimed in U.S.
Pat. No. 5,124,162. A mixture of flavor, maltose, malto-dextrin and
a carbohydrate film former by spray-drying the mixture to form a
dense product of at least 0.5 g/cc bulk free flow density and less
than 20% voids. The invention is intended to improve the stability
against oxidation of the flavor.
[0011] The production of microparticles useful in augmenting,
enhancing and/or imparting aroma and/or taste (over relatively long
periods of time in a controllably releasable manner) to perfume
compositions, perfumed articles (e.g., deodorancy and
antiperspirant sticks), foodstuffs, chewing gums, beverages and the
like is the subject of U.S. Pat. No. 6,368,633. The first step
reported in the invention is the adsorption of the olfactory-active
material onto silica followed by a blending/extrusion step followed
by at least one particularization step.
[0012] The U.S. Pat. No. 3,922,354 describes particulate
free-flowing flavoring compositions utilizing flavoring agents in a
cellular matrix of gelatinized cereal solids and water. Dextrins,
mixtures of edible mono and diglycerides of higher fatty acids, and
coloring agents can also be added to the matrix to provide a free
flowing product that exhibits controlled flavor release
characteristics, the aesthetic-appeal of natural whole or ground
spices, and precisely controlled flavor values and strength. By
forming a mixture of partially gelatinized cereal solids in water
and then heating with agitation to a temperature of from about 65
degree to about 100 degree Celsius until gelation takes place. A
water content of from about 10 to about 20 percent by weight is
achieved. The patent includes extrusion and grinding of the matter,
as well. A large particle size, high water content and low flavor
content are the disadvantages of the aforementioned invention.
[0013] Encapsulation of a flavor or active agent in a similar
matrix (i.e., whey protein) is claimed in U.S. Pat. No. 5,756,136.
The encapsulation composition that results in the controlled
release of the flavor or active agent may be incorporated in a
yeast-leavened dough without causing a deleterious effect on the
rising of the dough.
[0014] A number of U.S. patents (e.g., U.S. Pat. Nos. 6,325,859;
6,436,461; 6,929,814; 3,857,964) deal with the use of acid
polysaccharides (e.g., alginates) as embedding materials once
gelified by means of multivalent cation solutions. U.S. Pat. No.
6,325,859 claims the encapsulation of flavor, fragrance, vitamin,
and/or coloring materials then to be added to the food or tobacco
products. A similar procedure is described in U.S. Pat. Nos.
6,436,461 as well as 6,929,814.
[0015] U.S. Pat. No. 4,343,826 describes a process for preparing
beads of fat by melting a fat (that contains at least 20% solids at
a temperature below about 175 degrees F.) and cooling the melted
fat to a temperature about 3 degrees to 8 degrees F. below the
clear point of the fat. The method should allow the formation solid
drops at least 3 mm in diameter. In U.S. Pat. No. 5,460,756, a
method and apparatus to entrap liquids within wax and transforming
the wax to a more stable crystalline state is claimed. The aim is
achieved by placing the wax/liquid material in a chamber attached
to a piston and by applying some force with the piston.
[0016] In U.S. Pat. No. 6,245,366 a fat-coated encapsulation
compositions is prepared by mixing an active agent with a molten
fat to obtain a slurry, and cooling the slurry thereafter to obtain
a solid mass in which the active agent is embedded. The invention
mention also the use of various techniques (i.e., spray drying,
melt extrusion, coacervation, freeze drying, drum drying, belt
drying, tray drying, tunnel drying, and extrusion) to obtain fat
particles.
[0017] An encapsulation system composed of both hydrophobic and
hydrophilic material is described in U.S. Pat. No. 6,887,493. Solid
nanospheres of carnauba wax, candelilla wax, and mixtures thereof,
encapsulating a first active agent are embedded in micro spheres
made of a moisture sensitive matrix material (e.g., starch
derivative, natural gum, polysaccharide, protein,
hydrocolloid).
[0018] U.S. Pat. No. 3,976,794 describes sweetened coconut products
coated with a powdered sugar further containing sugar particulate
enveloped in edible fat. U.S. Pat. Nos. 3,949,094 and 3,949,096
show a process for preparing various flavorings, colorants, and
flavor enhancers coated with a mixture of fats and emulsifiers.
Here, the process consists of spraying flavors and condiments that
are intercepted by a second, impinging spray containing the edible
coating materials. These processes require the use of multiple
spray configurations, and afford relatively low flavor
encapsulation efficiency, the particles consisting primarily of
excipient materials.
[0019] U.S. Pat. No. 2,857,281 describes a process of forming a
hot, liquid emulsion of a volatile flavoring agent in a water
soluble, edible sugar matrix. This material is then forced through
an orifice to form flavored particulates. U.S. Pat. No. 2,785,983
discloses a process for making a flavoring composition by
spray-cooling a solution of the desired flavoring ingredient
dispersed in a melted, edible hard fat or hydrogenated glyceride
oil, thereby forming dry, solid flavored particles that are
water-insoluble. U.S. Pat. No. 4,173,492 discloses a process for
producing flakes of coated pigments for dry compounding with
polymeric plastics or rubber materials. Here, the color pigments
are encapsulated in a wax, such as hydroxystearate wax.
[0020] U.S. Pat. No. 4,675,236 reveals a process for coating
mono-core type shell-core microcapsules with waxes. The mono-core
type material is formed by spray drying or pulverizing bulk core
material, and the core materials are then immersed in a wax
solution, followed by vacuum drying. The product is then introduced
together with air or nitrogen gas into a melting and cooling
chamber, giving rise to a final wax-coated product with a smooth
surface and a shape similar to that of the underlying core
particle.
[0021] U.S. Pat. No. 3,856,699 describes a process for producing
capsules encased in walls of a waxy material. The process comprises
the dispersion of a waxy material containing a core material in an
agitated aqueous medium at a temperature higher than the melting
point of the waxy material, followed by transferring the waxy
material into a non-agitated aqueous medium at a temperature lower
than the melting point of the waxy material, thereby inducing the
formation of solid particles.
[0022] U.S. Pat. No. 3,819,838 describes a particulate solid
composition comprising multiple capsules, each consisting of at
least one primary capsule, wherein an active ingredient, such as a
flavor, is encapsulated by a water soluble solid encapsulating
material, whereupon the primary capsule is re-encapsulated in a
water insoluble-solid encapsulating material. The inventors note
that water soluble encapsulated materials, as described in the
prior art, are disadvantageous when mixed with other ingredients,
including water or moist ingredients.
[0023] U.S. Pat. No. 3,764,346 discloses a process for preparing
spray dried materials that may be employed as flavor enhancers.
[0024] In U.S. Pat. No. 5,328,684, Morgan et al. describe the
encapsulation of flavors, fragrances and related compounds in fatty
alcohols, waxes and in other substances, such as polymers, in a
process employing an apparatus comprising mixing and feed tanks,
gas inlets, heating elements and spray nozzles, and related
equipment.
[0025] In U.S. Pat. No. 6,190,722, Wedral et al. describe a process
for making flavored, free flowing particulates, which comprises
mixing an oil soluble flavor with a melted edible fat in a reaction
vessel to form a solution of the oil soluble flavor in the melted
fat, cooling the solution, adding a cooling or super-cooling agent
with agitation to produce solid particles having an average
diameter of from about 0.1 to 10 cm, or grinding these particles
with a supercooling agent in a grinder or blender to produce
substantially free flowing particulate flavor whose particles have
an average diameter of less than 1 mm. Wedral et al. note that the
use of a super-cooling agent is necessary to produce particles with
an average diameter of less than 1 mm, as the materials are
otherwise too sticky and adherent to be properly ground.
[0026] U.S. Pat. No. 5,064,669, Tan et al. reveals a method for
making controlled release flavors. Here, an aqueous flavoring agent
is dispersed in a melted encapsulating or enrobing material, such
as a fat and/or wax and one or more emulsifiers, mixing one or more
water-containing flavor compositions with a texture conditioning
agent, then mixing the flavor compositions and texture conditioning
agent(s) with the molten fat or wax to obtain a homogeneous mixture
in the form of an emulsion, and finally chilling the flavor
composition-containing mixture to provide discrete particles of
solid encapsulated flavoring agent. The process may require a spray
chiller to produce the particles, and produces a composition
containing a number of excipients, including emulsifiers and
conditioning agents, as well as the flavor itself.
SUMMARY OF THE INVENTION
[0027] Each of the representative prior art patents, discussed
above, has certain disadvantages as compared to the production of
the materials of the present invention. Several of these prior art
methods require specialized spray drying, mixing or extrusion
equipment, employ mixtures of several excipients, and may result in
the degradation or evaporation of flavors. Still others are limited
in the range of particle size that may be produced, as well as in
flavor loading as a percent of total material weight. The high
temperatures required in several of these aforementioned methods
may compromise flavor stability by thermal degradation and
encapsulation efficiency by inducing volatilization. Further, the
extensive use of polysaccharides and organic acids as primary
matrix and encapsulation materials may further impact flavor
stability promoting trans-esterification and other degradative
processes.
[0028] It is an object of the present invention to overcome these
disadvantages by providing a method for producing flavoring
materials consisting of a flavor and a simple matrix material that
are GRAS or approved for use in food, and that will be stable under
extremely adverse conditions, greater than 50% moisture, high Ph,
high temperature stability (60.degree. C.), yet be released in the
oral cavity.
[0029] It is a further object of the present invention to provide a
method of producing such materials at temperatures sufficiently low
so as to minimize volatilization and degradation of the additive
components during processing.
[0030] It is yet another object of the present invention to provide
a method to produce such materials that is more simple, more
scalable and more economical in comparison to the prior art
methods. These and other advantages of the present invention will
become apparent to one skilled in the art with reference to the
attached.
[0031] The present invention may be practiced using a simple
casting and grinding method that does not require chilling, or by a
simple aqueous emulsion cooling method using simple agitation
equipment. In contrast to previous methods, which require several
excipients, including plasticizers and emulsifiers, the present
invention may be practiced, and desired release characteristics
achieved, using a flavor and a single GRAS matrix material.
Moreover, in those cases where a plasticizer is desired, the
plasticizing properties of methyl salicylate itself might be
advantageously used in the formulation, further underscoring the
simplicity of the present method by obviating the need for
additional plasticizing agents.
[0032] Particle size may be controlled using simple adjustments to
the grinding-sieving process, or by simple alterations to the
aqueous emulsion agitation speed, cooling method and emulsifier
concentration. Percent flavor loading is possible across a wide
range simply by increasing or decreasing the amount of flavor
incorporated into the molten matrix material. The flavor release
rate, and the resistance of the particles to water imbibition and
hydrolysis, may be controlled by changing the matrix material
and/or the particle size. Additional advantages of the present
invention include the lack of organic solvents, and the use of
inexpensive materials and unsophisticated equipment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a diagram of the fused punch production process of
Example 1.
[0034] FIG. 1a is a differential scanning calorimetry (DSC)
thermogram of fused paraffin.
[0035] FIG. 2 is a DSC thermogram of fused paraffin and methyl
salicylate.
[0036] FIG. 3 is a DSC thermogram of fused cetyl alcohol.
[0037] FIG. 4 is a DSC thermogram of fused cetyl alcohol and methyl
salicylate.
[0038] FIG. 5 is a DSC thermogram of fused palmitic acid.
[0039] FIG. 6 is a DSC thermogram of fused palmitic acid and methyl
salicylate.
[0040] FIG. 7 is a DSC thermogram of fused PEG 8000.
[0041] FIG. 8 is a DSC thermogram of fused PEG 8000 and methyl
salicylate.
[0042] FIG. 9 is a DSC thermogram of fused cholesterol.
[0043] FIG. 10 is a DSC thermogram of fused cholesterol and methyl
salicylate.
[0044] FIG. 11 is a graph illustrating methyl salicylate release
from fused punches in artificial saliva at 37.degree. C.
[0045] FIG. 11a is a diagram of the fused punch production process
scheme of Example 3.
[0046] FIG. 12 is a diagram of glass bead dissolution apparatus for
particles and tobacco.
[0047] FIG. 13 is a graph illustrating methyl salicylate release
from fused particles in artificial saliva at 37.degree. C.
[0048] FIG. 14 is a graph illustrating methyl salicylate release
from fused particles dispersed in high dark snuff in artificial
saliva at 37.degree. C.
[0049] FIG. 14a is a diagram of the fused punch production process
scheme of Example 4.
[0050] FIG. 15 is a graph illustrating methyl salicylate release
from methyl salicylate-loaded cetyl alcohol particles dispersed in
high dark snuff in artificial saliva at 37.degree. C.
[0051] FIG. 16 is a graph illustrating methyl salicylate release
from methyl salicylate-loaded cetyl alcohol particles dispersed in
methyl salicylate-adsorbed high dark snuff in artificial saliva at
37.degree. C.
[0052] FIG. 16a is a diagram of the rapid cooling production
process scheme of Example 6.
[0053] FIG. 17 is a bar graph illustrating the particle size of
Batch # 6.
[0054] FIG. 18 is a graph illustrating in vitro release profiles
for formulation 9b.
[0055] FIG. 19 is a graph illustrating in vitro release profiles of
formulations reported in Table 5.
[0056] FIG. 20 is a color version of optical microscopy of Batch
SB10(5), magnified 100.times. in the upper pictures, and 200.times.
in the lower pictures.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0057] The present invention will now be described by way of
certain Examples that illustrate the preferred embodiments of the
invention to date.
Example 1
[0058] Experiments to date have demonstrated a high capacity for
waxes to absorb and disperse methyl salicylate (e.g., as much as
15% in paraffin). In addition, methyl salicylate-loaded wax
particles have been produced by dispersion of a molten wax-methyl
salicylate solution in hot aqueous ethanol with rapid agitation and
cooling.
[0059] The evaluation of a series of GRAS materials for use as
sustained-release methyl salicylate matrices has led to the
selection of cetyl alcohol and PEG 8000 as promising candidates.
Cetyl alcohol affords steady, reproducible yet delayed methyl
salicylate release in artificial saliva. PEG 8000-methyl salicylate
dispersions lead to a burst of methyl salicylate, with a more
delayed release when dispersed in tobacco.
[0060] Self-emulsified cetyl alcohol particles prepared from
aqueous emulsions also give relatively steady, sustained delivery.
Flavored cetyl alcohol particles, combined with neat methyl
salicylate dispersed in tobacco, offer another alternative
flavoring method.
[0061] Fused solid dispersions have been employed throughout the
food, pharmaceutical and cosmetic industries in a variety of
applications, including the storage and controlled release of
flavors, fragrances and other actives. Fused dispersions, also
referred to as `melts` or `solid solutions`, are made by blending a
component, such as methyl salicylate, into molten GRAS materials at
moderate temperatures. The molten solution may be molded, extruded,
sprayed as a coating or spray-cooled into particles. The cooled
fusate may also be molded, punched or milled into particles. Fused
dispersions may be prepared from many self-emulsifying materials,
and require little or no additional solvents or excipients. Since
minimal excipients are desirable in any sustained-release flavor
preparation, fused dispersions have been explored as a possible
formulation method.
[0062] A series of GRAS carrier materials were selected and
evaluated as potential matrices for producing methyl
salicylate-loaded particles for controlled sustained delivery.
Dental-grade paraffin, cetyl alcohol and its carboxylate analog,
palmitic acid, PEG 8000 and cholesterol were employed in these
initial studies. All of these edible materials are routinely
incorporated into foods and oral preparations. These materials were
selected in order to compare the influence of chemical structure,
including the presence of hydrogen bond donors and/or acceptors,
hydrophilic and hydrophobic functions and the sterol backbone on
release performance. All of these materials will mix and melt with
methyl salicylate and form solid dispersions. However, at methyl
salicylate concentrations beyond ca. 20% w/w, the fusates tend to
become tacky, smearing semi-solids. Accordingly, 20% w/w was chosen
as the methyl salicylate concentration for the initial particle
studies.
[0063] In a typical experiment to date, 1 gram of carrier material
was melted in a glass vial at approximately 65.degree. C. in a
water bath. Upon melting, 250 mg of methyl salicylate (20% w/w) was
added with stirring. Since the melting point of cholesterol is ca.
148.degree. C., it was necessary to add 1 mL of dichloromethane to
the cholesterol-methyl salicylate mixture in order to produce a
liquid dispersion. The vials were immediately sealed and removed
from the heat source. The melts were then allowed to cool to room
temperature. Uniform fusates approximately 2 mm in thickness were
thus formed on the bottom of each flat-bottomed vial. No creaming
or phase separation was noted in any fusate during or after
cooling. The fused dispersions were then dried under reduced
pressure (330 mm Hg) for 24 hours.
[0064] A flow diagram of the fusate production process is shown in
FIG. 1.
[0065] The fusates were then assayed for methyl salicylate content
and homogeneous distribution by randomly sampling round `punches`
with a 6 mm cork borer and dissolving each `punch,` normalized by
weight, in methanol. The methanol solutions were then assayed for
methyl salicylate and salicylic acid content by reverse phase HPLC
with UV detector. Methyl salicylate content was nearly quantitative
(20% w/w) in each preparation. Notably, although the scent of
methyl salicylate was evident, each material appeared to have a
high affinity for methyl salicylate. No significant weight loss was
noted from any fusate, even after 72 hours under reduced pressure.
Methyl salicylate remains stable under these processing conditions,
as no salicylic acid was detected by HPLC in any fused
dispersion.
[0066] Thermal analysis of solid dispersions is routinely performed
using differential scanning calorimetry (DSC) for both analytical
and quality control purposes. DSC may be used to characterize the
crystalline and amorphous characteristics of the materials under
study, thereby providing insight into chemical and functional
interactions between carrier and flavor. This information may be
useful for predicting and understanding wetting, solubility,
plasticizing effects and release behavior. DSC is useful for
validating the polymorphic character and its reproducible
production in solid dispersions. The influence of casting, milling
and spraying on these dispersion characteristics may also be
assessed with DSC.
[0067] Accordingly, DSC analysis of the fused carrier controls and
their corresponding methyl salicylate dispersions was performed in
order to gain an initial appreciation of the tendency, if any, of
methyl salicylate to plasticize or otherwise interact with each
carrier. Fused paraffin (FIG. 1a) melts at approximately 60.degree.
C., with changes in heat capacity around 40.degree. C. and
60.degree. C.
[0068] The paraffin-methyl salicylate dispersion (FIG. 2) shows a
broadened change in heat capacity and a modest melting point
reduction, suggesting a tendency for methyl salicylate to interact
with linear aliphatic molecules.
[0069] A similar change in thermograms was noted for fused cetyl
alcohol (FIG. 3), a long chain aliphatic alcohol, and the cetyl
alcohol-methyl salicylate dispersion (FIG. 4).
[0070] In contrast, both fused palmitic acid (FIG. 5), the
carboxylate analog of cetyl alcohol, and its corresponding methyl
salicylate dispersion (FIG. 6), gave rise to similar thermograms,
suggesting less interaction than with the alcohol.
[0071] Based upon these initial DSC data, it is possible that
methyl salicylate has a greater tendency to interact with
hydroxyl-containing compounds than with those containing a
carboxylate group
[0072] Fused PEG 8000 (FIG. 7) and the PEG 8000-methyl salicylate
dispersion (FIG. 8) show similar thermal properties, with only a
very modest change in the heat capacity of PEG 8000, and a modest
broadening in the peak, suggesting an interaction between methyl
salicylate and PEG. The tendency of methyl salicylate to interact
with longer chain aliphatics and hydrogen bond donors, as compared
to PEG, a relatively polar, hydrophilic hydrogen bond acceptor,
might be expected to differ. Although no particular functional or
structural trend is determined from these data, it appears that
methyl salicylate may interact with a variety of matrix materials,
suggesting the possibility that methyl salicylate might mix with or
otherwise be incorporated into matrices comprising certain
materials employed in these studies.
[0073] Similarly, an examination of the DSC thermograms of fused
cholesterol (FIG. 9) and the cholesterol-methyl salicylate mixture
(FIG. 10) reveals a greater tendency for methyl salicylate to
interact with hydroxyl-containing aliphatics. In fact, a depression
of about 10.degree. C. was observed with cholesterol after blending
with methyl salicylate. These data may be useful for the rational
selection of matrix materials and optimization of methyl salicylate
formulations.
Example 2
[0074] Individual flavor reservoirs or some other type of
`flavor-pak` might be included in a snuff can or in a snuff pouch
for sustained flavor release. Alternatively, snuff might be
incorporated directly into such a flavored matrix in order to make
a buccal pellet. Such a reservoir or pellet might be comprised of a
tablet, a punch or some other flavor-matrix mass. Accordingly, an
initial evaluation of the release characteristics of methyl
salicylate from the solid dispersions was performed using fused
punches. These punches, rather similar to a tablet, were prepared
by removing a uniform, 6 mm diameter disc from a 2 mm thick solid
dispersion produced as described in the scheme of FIG. 1. The
punches, uniform in size and surface area, were homogeneous in
methyl salicylate content (20% w/w). Normalized for weight, the
punches were placed in a 20 mL glass vial, and 10 mL artificial
saliva (see p. 30, para. 3; Na et al.) was gently added with slow
stirring at 37.degree. C. At the indicated time point, a 1 mL
aliquot part of the artificial saliva was removed for assay and
replaced with 1 mL of fresh artificial saliva, thereby simulating a
sink condition. The sample was dissolved in 4 mL 50% methanol to
ensure dissolution, and then assayed for methyl salicylate content
by HPLC, and cumulative release was calculated after correcting for
volume. As a control, an amount of neat methyl salicylate
equivalent to that contained in the pellets was dispersed on the
bottom of control vials, and its dissolution was analogously
assayed. The results of this study, presented as the mean.+-.SD of
three independent experiments, are summarized in FIG. 11.
[0075] The PEG 8000 pellet, primarily comprised of a hydrophilic
polymer, rapidly dissolved into a wet mass in the vial. Not
surprisingly, methyl salicylate release was most rapid from the PEG
8000 punch. A burst of flavor release was noted within the first
few minutes of dissolution. PEG, a well-known hydrotrope and
wetting agent with significant surface active properties, may be
useful for providing a flavor burst in a methyl salicylate
formulation, or as a burst coating on a delayed-release
composition.
[0076] As compared to the control, the more hydrophobic matrices
all retarded the release of methyl salicylate. Since these punches
were solid castings, release was likely a function of
solubilization of methyl salicylate located on the punch surface,
as well as diffusion and solubilization of methyl salicylate
trapped in the interior. Cetyl alcohol, which has modest surface
activity, is a major component of commercial self-emulsifying
waxes. Cetyl alcohol also gave the steadiest release profile. Given
these characteristics, cetyl alcohol may be among the more
promising matrix materials tested so far.
Example 3
[0077] As stated, the punches described in the previous Example
afford both an initial assessment of methyl salicylate release from
the various matrix materials, as well as a proof of concept model
for flavor release from an individual reservoir. Flavor-loaded
matrix particles, which might be dispersed into loose, tinned
snuff, offer another option for sustained-release delivery. Size,
color and texture could be optimized for flavor delivery and
consumer acceptance. The larger surface area-to-volume ratio of
particles may offer more rapid flavor release. In addition, several
methods are available for the production of such particles,
including comminution of a solid dispersion, spraying molten
solutions and various emulsion technologies.
[0078] A series of methyl salicylate particles were produced by
grinding the cooled solid dispersions previously described in a
glass mortar and pestle, then passing the particles through
standard testing sieves. Light microscopy revealed that the
particles that were ground and sieved to a fraction between 75 and
250 .mu.m in size were generally fractured and irregular in shape.
The particles were assessed for methyl salicylate content and
homogeneity by HPLC. The grinding did not affect the properties of
the particles.
[0079] As the material tended to smear and clog the screens, the
cholesterol-methyl salicylate fusate could not be comminuted and
sieved into discrete particles. Thus, it was not further evaluated
as a particle matrix. Instead, a 1:1 w/w mixture of two of the
other matrix materials, cetyl alcohol and PEG 8000, was used
instead.
[0080] A flow diagram of the flavored particle production process
is provided in the scheme of FIG. 11a.
[0081] Dissolution studies, analogous to those described for the
punches, were then performed. Because the particles are buoyant,
and in order to model the `cheek and gum` structure of snuff held
in the mouth, the particles (50 mg, 10 mg methyl salicylate
equivalent) were first sandwiched between two layers of inert glass
beads (1 mm): The beads tended to keep the particles in place in a
defined layer. At the same time, artificial saliva freely flowed
through the Plateau border channels between the beads on both sides
of the particle layer, in a manner analogous to saliva flow in the
buccal pouch. These dissolution apparatuses, illustrated in FIG.
12, were also used for the tobacco studies and flash melt film
studies described in later sections.
[0082] The dissolution apparatus consists of a 20 mL glass vial
containing 10 mL artificial saliva and two 1 gram layers of glass
beads, between which may be sandwiched a layer of particles, a
flash melt film, a wad of tobacco, or another dosage form.
[0083] Methyl salicylate release from the fused particles, as
compared to an equivalent amount of neat methyl salicylate
distributed between the beads, is summarized in FIG. 13.
[0084] The results are expressed as the mean.+-.SD of three
independent experiments. Once again, PEG 8000 produced a rapid
methyl salicylate burst. Cetyl alcohol displayed consistently
slower release as compared to the methyl salicylate control.
Palmitic acid gave mixed results, with release approximating that
of methyl salicylate early on, followed by slower release, perhaps
due to depletion of surface methyl salicylate and/or the formation
of a stagnant film. Cetyl alcohol gave its characteristically
steady, retarded release profile throughout the experiment. Since
it has surfactant and self-emulsifying properties, it may form a
stagnant film that tends to retard methyl salicylate release.
Notably, the cetyl alcohol-PEG 8000 composite afforded an initial
burst of methyl salicylate, followed by release that was slower
than methyl salicylate itself. This combination may be particularly
useful for manufacturing composite particles with both
characteristics. It may be possible to minimize the use of
additional excipients simply by manufacturing these composite
particles in various cetyl alcohol/PEG ratios.
[0085] In order to model particle performance when dispersed in
tobacco, as well as to examine the effect of tobacco dispersion on
methyl salicylate release, an analogous set of experiments was
performed in which the particles (50 mg, 10 mg methyl salicylate
equivalent) were first dispersed in 500 mg of high dark snuff, then
sandwiched between the bead layers in the dissolution vials, as
shown in FIG. 12. Assays revealed that the particles were uniformly
dispersed. In addition, no methyl salicylate was detected in
extracts of the tobacco itself, which is known to synthesize methyl
salicylate as a chemical signal when stressed. Methyl salicylate
release from the fused particles dispersed in tobacco, as compared
to an equivalent amount of neat methyl salicylate adsorbed on
tobacco, is summarized in FIG. 14.
[0086] Neat methyl salicylate release, as well as methyl salicylate
release from the palmitic acid and cetyl alcohol particles, was not
significantly affected by dispersion in tobacco. This suggests that
artificial saliva and methyl salicylate diffusion are not
significantly altered by the presence of tobacco. In addition, the
presence of any surface or chemically active tobacco components, if
any, did not alter the dissolution characteristics of methyl
salicylate itself. This is particularly important in light of the
vast change in methyl salicylate release noted with the PEG 8000
particles. While the punch and free particle experiments revealed a
tendency for PEG 8000 to produce a rapid methyl salicylate burst,
when dispersed in tobacco, the PEG 8000 and, to a lesser extent,
the PEG 8000-cetyl alcohol particles, manifested a distinct
reduction in release rate. It is not likely that the chemical
stability or surface activity of PEG, a non-ionic poly-ether, are
going to be adversely affected in the presence of tobacco. The DSC
experiments suggest that methyl salicylate does not appreciably
interact with PEG. One possible explanation for the reduction in
release rate may be that, in lieu of any electrostatic interaction,
dispersion and confinement in the tobacco matrix may induce the
formation of a PEG hydrogel or stagnant film. The film may cause a
diffusion rate limited release of methyl salicylate. The
observation that PEG tobacco dispersions may retard flavor release
has potential in more advanced sustained-release applications. At
the same time, PEG provides a formulation challenge, as its high
affinity for water, and the high water content of tobacco (55%),
may compromise particle integrity, and thus flavor encapsulation,
on product storage.
Example 4
[0087] The mechanical comminution of solid dispersions is a ready
way to produce particles. However, mechanically processed particles
may be irregular in shape, as demonstrated in the previous Example.
In addition, polymorphic changes may be induced during the size
reduction process. Solid dispersions produced by cooling melted
matrix emulsions may be another useful means for producing methyl
salicylate-loaded particles. When dispersed in aqueous media,
lipophilic compounds tend to minimize interfacial surface area and
surface free energy by spontaneously forming spheres. Upon cooling,
the liquid oil phase droplets solidify, producing discrete
spherical particles. Depending upon the temperature, shearing
method and auxiliary surfactants employed during the emulsification
process, uniform, spherical particles are readily and reproducibly
manufactured.
[0088] Sophisticated flavor emulsions and microencapsulated systems
have been manufactured using a variety of emulsion techniques.
However, one goal of the research completed to date has been to
produce sustained-release flavor matrices while using a minimum of
excipients. Thus, the GRAS materials employed in the previous
Examples were assessed for their capacity to form flavor-loaded
particles using the melting-cooling emulsion technique without
additional excipients. PEG was not evaluated in these aqueous
emulsion studies, as it is readily dissolved in water. Future PEG
emulsion studies may be performed in an appropriate
antisolvent.
[0089] In a typical melting cooling emulsion experiment, 1 gram of
matrix material (cetyl alcohol, paraffin, palmitic acid or
cholesterol wetted with dichloromethane) was melted at 65.degree.
C. As soon as the material was melted, serial amounts of methyl
salicylate were added, vigorous agitation on a stirring plate was
commenced, and 100 mL of deionized water, previously heated to
65.degree. C., was added over 60 seconds. The heat was removed, and
the emulsion, consisting of melted matrix-methyl salicylate
droplets dispersed in water, was allowed to cool to room
temperature. After the droplets formed hard microcapsules, they
were collected using a 10 .mu.m filter, washed with 10 mL cold
water, and air-dried overnight. The resulting particles were
spherical in shape, generally free-flowing and non-adherent. FIG.
14a provides a diagram of the procedure employed for producing
flavored particles from aqueous dispersions.
[0090] Cetyl alcohol was the only matrix material that formed
suitable particles under these minimal conditions. The others
tended to form large agglomerates and sheets that varied
substantially in size and shape. Thus, cetyl alcohol was chosen as
the model emulsion matrix material. In order to determine the
maximum loading capacity of cetyl alcohol, analogous experiments
were conducted using increasing amounts of methyl salicylate. As
summarized in Table 1, methyl salicylate incorporation into the
cetyl alcohol particles was nearly quantitative up to about 33%
w/w, beyond which the material became soft and gel-like.
TABLE-US-00001 TABLE 1 Production of methyl salicylate-loaded cetyl
alcohol particles by melting-cooling in an aqueous oil-in-water
dispersion. Methyl Salicylate Content Methyl Salicylate
Encapsulation (mg) % by Weight % Yield Theoretical Actual 100 9
94.5 9 9.2 200 16.7 96.0 16.7 12.8 250 20 93.1 20 19.9 500 33 90.2
33 31.3 750 43 34.0 43 30.9 1000 50 0 (gel) 50 0 (gel)
[0091] The particles were rather large, perhaps due to the lack of
an emulsifier and high-shear mixing. [0092] The particles were also
polydisperse in size, as shown in Table 2. The 33% w/w methyl
salicylate emulsion system gave rise to smaller particles.
TABLE-US-00002 [0092] TABLE 2 Size range of isolable methyl
salicylate-loaded cetyl alcohol particles. Particle Type >500 um
250-500 um 75-250 um <75 um 20% Methyl 19.4 75.9 4.6 0
Salicylate 33% Methyl 0 89.8 7.6 2.5 Salicylate
[0093] Methyl salicylate remained stable throughout the process, as
no salicylic acid was detected when the particles were assayed for
methyl salicylate content and homogeneity. Clearly, more
sophisticated emulsion methods could be employed to produce
smaller, more uniform particles. Nevertheless, these initial
studies demonstrate that spherical methyl salicylate-cetyl alcohol
particles may be reproducibly manufactured without excipients using
the simplest techniques. Methyl salicylate release from the
emulsified cetyl alcohol particles is summarized in FIG. 15.
[0094] The influence of methyl salicylate loading (20 or 33% w/w)
and particle size (75-250 nm or 250-500 nm sieve fractions) were
evaluated. Using the aforementioned glass bead release apparatus
described in FIG. 12, the particles (10 mg methyl salicylate
equivalent) or the neat methyl salicylate control were placed
between the glass bead layers, and release studies in artificial
saliva at 37.degree. C. were performed as described in the previous
sections. Methyl salicylate release from the emulsified cetyl
alcohol particles was slower than neat methyl salicylate
dissolution, regardless of particle loading or size. This suggests
that cetyl alcohol remains a viable choice for sustained flavor
release. As would be expected, release was faster from the smaller
particles, which have a much higher surface area to volume ratio.
Particle size appears to have a greater influence on methyl
salicylate release than percent loading, as release from the
smaller 20% w/w particles was significantly faster than that from
the larger 33% w/w particles.
[0095] Tobacco is currently flavored by maceration and coating with
methyl salicylate. Combining this method with a sustained-release
preparation has produce superior flavor release in experiments
completed to date. In one experiment 250-500 .mu.m cetyl alcohol
particles (20 or 30% w/w, 10 mg methyl salicylate equivalent) were
dispersed in 500 mg high dark snuff with or without 10 mg free
methyl salicylate and the neat control, and the release experiment
was repeated. The results of these experiments are shown in FIG.
16.
[0096] Methyl salicylate release from the particles dispersed in
tobacco was little changed from that released from the equivalent,
free particles, as summarized in FIG. 15 and previously discussed.
Methyl salicylate release from the tobacco containing both free and
encapsulated methyl salicylate approximated the sum of that
released from the particles alone plus that released from the neat
control. These data suggest that methyl salicylate release is
simply additive when both encapsulated and free methyl salicylate
are dispersed in tobacco.
[0097] It was a further object of the research completed to date to
further modify the aforementioned flavored particle production
methods in order to optimize the liposphere particle size, to
possibly .about.100 .mu.m or smaller, and to increase the drug
content up to 10-20%. These two characteristics were determined to
be of fundamental significance after the in vitro assay of the
previously produced batches. Large particles were perceived when in
the mouth and an oily sensation was also felt. This would cause
acceptability problems for customers. The increase of the flavor
content up to 10-20% was believed to be useful to reduce the amount
of particulate material in the final product (e.g., tobacco) and to
optimize the process and to reduce the overall cost, as well.
[0098] In a typical experiment of the previous Examples, the needed
amount of methyl salycilate was added to 1 g of melted (65.degree.
C.) cetyl alcohol (CA) and 100 mL of deionized water, which were
heated at the same temperature, and were the poured over a 60
second time period onto a stirring plate while under vigorous
agitation. The dispersion was cooled to room temperature, and the
formed particles were collected by filtration, were washed with
cold water and were air-dried overnight.
Example 5
[0099] The main improvements focused on how the internal phase is
dispersed into the external phase and the agitation procedure. In
the modified method the melted internal phase (2 g of CA and the
needed amount of methyl salycilate) are injected via a plastic
syringe into 400 mL of deionized water (with or without surfactant)
heated at 65.degree. C. and agitated with mechanical stirring.
After injection the heating was discontinued and the dispersion was
allowed to cool at room temperature. Particles were recovered by
filtration, were washed with 3 L of deionized water and were dried
under vacuum overnight (15 mm Hg). The different preparations
performed with Example 5 are reported in Table 3, while the
particle size of the batch number 6 is shown in FIG. 17.
[0100] Not all the performed preparations gave rise to particle
formation (Table 3). The optimal stirring rate was found to be 1000
rpm when deionized water was used as the external phase, while 500
rpm when 0.35% of poly (vinyl alcohol) was added. Batch # 2 formed
very large particles clearly visible, most likely in the range
between 500 and 1000 .mu.m; therefore not suitable for their
particle size. Preparation #4 provided smaller particles and this
preparation was repeated adding methyl salicylate (23.1% of target
loading). The preparation was performed in triplicate (batches #6,
7 and 8 in Table 3). The particle recovery was satisfactory
(.about.80%), while the mean encapsulation efficiency (.about.35%)
and the methyl salicylate content (8%) were considered too low
(Table 3). The particle size of these three batches was considered
satisfactory (FIG. 17). The low active content was ascribed to the
evaporation of the volatile methyl salicylate during the time that
the dispersion was allowed to cool at room temperature without any
external cooling.
[0101] Flavor lost during encapsulation has been reported to be an
issue. In fact some prior art processes (i.e., U.S. Pat. Nos.
5,601,865; 5,792,505 and 5,958,502) have employed a pressure
sufficient to prevent substantial volatilization of the volatile
component.
Example 6
[0102] In order to achieve higher actual content, to reduce to a
minimum the flavor volatilization, and to achieve smaller more
desirable particles with a narrower size range without the need for
grinding, the above reported method was further modified.
[0103] In the modified method, the cooling process has been
accelerated in order to decrease the loss of the volatile flavor
during this phase. Practically, after the internal phase injection
the emulsion was held at 65.degree. C. for 5 min and was then
transferred to an ice bath always under stirring. The other steps
were unchanged. The scheme of FIG. 16a provides a diagram of the
procedure. The results obtained are reported in Table 4.
[0104] Batch 9 differs from Batches 6, 7 and 8 only in the
processing (Example 6 instead of Example 5). The rapid cooling in
ice bath substantially increases the encapsulation efficiency up to
.about.60%, leading to an actual content close to 15%. Assays were
made to enhance the active content even though 15% can be
considered suitable. By increasing the target loading, it was
possible to achieve an actual loading of .about.23% (batch 10 in
Table 4).
[0105] Batches 9, 10, and 11 were performed in a replicate of 3 and
the results are shown in Table 4. The three formulations gave mean
methyl salicylate contents of 10.8, 15.0 and 18.2%, respectively.
The method yield was about 80% for almost all the preparations
(Table 4). Particles from Batches 6-10 did not give any oily
sensation in the mouth or in the hands.
TABLE-US-00003 TABLE 3 Preparations made with the method of Example
5 Batch Internal Methyl External Phase Stirring Encapsulation
Actual Active # Phase Salicylate 400 mL (rpm) Recovery Efficiency
Content Notes 1 Cetyl Alcohol -- Water 500 -- -- -- No particle (2
g) formation 2 Cetyl Alcohol -- Water 1000 -- -- -- Particles (2 g)
3 Cetyl Alcohol -- Water 1250* -- -- -- Coagulate (2 g) 4 Cetyl
Alcohol -- Water + 0.35% 500 87% (1.87 g) -- -- Particles (2 g) PVA
5 Cetyl Alcohol -- Water + 0.35% 1000 -- -- -- Coagulate (2 g) PVA
6 Cetyl Alcohol 0.6 g (30%) Water + 0.35% 500 84.9% (2.206 g) 30.2%
7.5% Particles (2 g) PVA 7** Cetyl Alcohol 0.6 g (30%) Water +
0.35% 500 87% (2.003 g) 37.5% 8.8% Particles (2 g) PVA 8** Cetyl
Alcohol 0.6 g (30%) Water + 0.35% 500 77% (2.289 g) 36.8% 8.4%
Particles (2 g) PVA *Stirring was kept to 1250 upon until the
suspension temperature dropped to 30.degree. C., when it was
lowered to 500 rpm. **Batches # 7 and 8 are replicates of Batch #
6.
TABLE-US-00004 TABLE 4 Preparations made with the method of Example
6 Encapsu- lation Actual Batch Internal Methyl Recovery Efficiency
Content # Phase Salicylate (%) (%) (%) 9 Cetyl Alcohol 0.6 g (30%)
97.2 61.7 14.2 (2 g) 9a Cetyl Alcohol 0.6 g (30%) 84.6 40.9 9.45 (2
g) 9b Cetyl Alcohol 0.6 g (30%) 85.5 37.4 8.60 (2 g) 10 Cetyl
Alcohol 1.0 g (50%) 65.0 39.8 13.2 (2 g) 10a Cetyl Alcohol 1.0 g
(50%) 80.2 53.1 17.7 (2 g) 10b Cetyl Alcohol 1.0 g (50%) 81.7 42.6
14.2 (2 g) 11 Cetyl Alcohol 1.5 g (75%) 89.8 51.9 22.8 (2 g) 11a
Cetyl Alcohol 1.5 g (75%) 83.4 34.4 15.1 (2 g) 11b Cetyl Alcohol
1.5 g (75%) 79.7 38.4 16.8 (2 g)
[0106] In vitro release of the Batch 9b was performed in
triplicate. In order to respect the infinite sink conditions, the
miscibility of methyl salicylate with artificial saliva and
deionized water at 37.degree. C. were assessed. The miscibility
resulted to be 0.77 and 0.79 mg/mL, respectively.
[0107] The following in vitro release method was used. A weighed
amount of particles was placed in a 20 mL scintillation vial filled
with 10 mL of artificial saliva and stirred with a magnetic bar. At
predetermined time points, 1 mL of media was carefully withdrawn
using a 1 mL syringe provided with a 0.2 .mu.m filter. The fresh
media was added through the same filter in order to recover all the
particles previously stopped on the filter. The filter was
validated before utilization. Release was performed at 37.degree.
C. at a stirring rate of 150 rpm.
[0108] The artificial saliva was composed of the following: Sodium
chloride, 0.844 g; potassium chloride, 1.200 g; calcium chloride
dihydrate, 0.193 g; magnesium chloride hexahydrate, 0.111 g;
potassium phosphate dibasic, 0.342 g; and water to make to 1000 ml.
The pH was adjusted with hydrochloric acid solution to pH
5.7.+-.0.1.
[0109] An example of the release profile of the particles of Batch
9b is given in FIG. 18. The in vitro release study was performed in
triplicate. The 3 release profiles are practically overlaying one
another, proving a good reproducibility of the employed method and
an homogeneity of the particles in the Batch. Only about 50% of the
initial content was found in the release media. This may be
explained by hypothesizing some methyl salicylate loss during the
sampling process that could be avoided using more appropriate
headspace sampling techniques (i.e., static or dynamic headspace
sampling).
[0110] After a positive panel evaluation of the 3 Batches (9, 10,
and 11) (Table 4), Batch 10 was chosen as the best formulation
mainly on the basis of the intermediate flavor content. Moreover,
the formulation of Batch 9 looked to be not very reproducible and
the content was still too low, while the formulation of Batch 11
showed some stability issue during storage at room temperature.
Methyl salicilate was found to be localized on the surface of the
particles, rendering a "wet" appearance at the glass vial wall. The
high flavor content may explain this behavior.
[0111] Cethyl alcohol crystals should be less ordered in the
particles with respect to the raw material because of the addition
of methyl salicylate behaving as an impurity in the crystal
lattice. The storage allows crystals to reorganize better,
provoking a squeezing effect on the encapsulated flavor. The
partial localization of the flavor on particle surface, due to the
high active content, should be accounted for, as well. The same
behavior was not observed for formulations of Batches 9 and 10.
Example 7
[0112] The first attempt to scale up was to a batch size of 15 g.
10 g of cetyl alcohol and 5 g of methyl salicylate were melted
(65.degree. C.) and injected into 2 L of deionized water,
containing 0.35% of poly (vinyl alcohol), heated at 65.degree. C.
under agitation with mechanical stirring (500 rpm). 5 minutes after
injection the heating was discontinued and the dispersion was
cooled using an ice bath. Particles were recovered by filtration,
washed with 6 L of deionized water and dried under vacuum overnight
(15 mm Hg). Characteristics of the obtained particles are reported
in Table 5.
[0113] Particles showed a mean flavor content of 13.8.+-.1.1% and
an encapsulation efficiency of 41.6.+-.3.2%; while the preparation
method had a yield of 86.9.+-.2.8%. The high reproducibility of the
method is proven by the low standard deviations obtained for both
the encapsulation efficiency and the product yield (Table 5).
[0114] For the 5 preparations, 90% of the particles were smaller
than 90 .mu.m and 50% were in the 40-48 .mu.m range. Similar
particle size is another indication of good method
reproducibility.
TABLE-US-00005 TABLE 5 Characteristics of the particles obtained
with the scaled up method. Methyl salicylate Encapsulation Batch
content efficiency Method yield Particle size .sup.b name (%)
.sup.a (%) (%) D(v, 0.1) D(v, 0.5) D(v, 0.9) 10(1) 13.7 41.0 83.0
(12.452 g) 13.4 .mu.m 44.5 .mu.m 85.7 .mu.m 10(2) 15.7 47.0 87.7
(13.158 g) 14.9 .mu.m 47.9 .mu.m 87.2 .mu.m 10(3) 13.0 39.0 86.8
(13.026 g) 12.6 .mu.m 40.7 .mu.m 83.5 .mu.m 10(4) 13.1 39.4 86.2
(12.925 g) 17.5 .mu.m 48.0 .mu.m 86.6 .mu.m 10(5) 13.8 41.4 90.7
(13.607 g) 18.4 .mu.m 47.7 .mu.m 86.2 .mu.m .sup.a Target load
33.33%; Batch size 15 grams. .sup.b D(v, 0.1), D(v, 0.5), D(v, 0.9)
represent 10, 50, 90% of particles smaller than that size.
[0115] FIG. 19 shows the release profiles (performed in duplicate)
of the 5 Batches reported in Table 5 that were obtained using the
release method previously described.
[0116] The release profiles demonstrate a low intra- and
inter-batch variation, again confirming the good method
reproducibility. As previously observed, the appearance of the
flavor in the release media was limited to the 40-50% of the total
amount employed for the study (FIG. 19). In order to confirm the
loss of the volatile matter, mass balance studies were performed.
Together with the 2 samples employed in the release study, 2 extra
samples for each batch were placed in the same conditions and kept
closed. Only one sampling was done at the 60 minute time point.
Then the samples (microparticles and release media, 10 mL) were
mixed with 30 mL of methanol to dissolve all the methyl salicylate
(flavor left in the particles and present in the release media) and
assayed at the HPLC. Results of this study are reported in Table 6.
The samples in a closed container released always higher amounts of
flavors at 60 minutes (about 70%) (Tab. 6). The amount lost was
estimated to be lower for the samples assayed only once, never
higher than .about.20%, while the other samples showed a loss
always around 30-40% of the initial amount. This confirms the
previous hypothesis.
TABLE-US-00006 TABLE 6 Results of the mass balance study. Amount
Amount Amount left in the Amount Sample released after recovered
microparticles lost name Sample 60 minutes (%) (%) (%) (%) SB10(1)
a* 52.9 56.0 3.1 44 b* 52.4 49.6 -- 50.4 c** 71.4 86.7 15.3 13.3
d** 72.2 79.8 7.6 20.2 SB10(2) a* 39.2 61.4 22.2 38.6 b* 39.1 59.7
20.6 40.3 c** 69.0 91.5 22.5 8.5 d** 60.6 82.5 21.9 17.5 SB10(3) a*
45.7 60.7 15 39.3 b* 45.7 60.1 14.4 39.9 c** 72.4 86.0 13.6 14 d**
71.7 92.6 20.9 7.4 SB10(4) a* 49.1 69.9 20.8 30.1 b* 46.1 66.3 20.2
33.7 c** 70.4 91.3 20.9 8.7 d** 70.2 91.4 21.2 8.6 SB10(5) a* 44.2
54.0 9.8 46 b* 44.9 56.0 11.1 44 c** 68.0 79.6 11.6 20.4 d** 67.1
81.0 13.9 19 *Samples employed in the release study **Samples
assessed for the release only at 60 minutes
[0117] Since the particles will have to release their content in
the mouth, a "non-closed system," the release conditions used for
the release (FIG. 6) should mimic more closely the real life
situation (flavor dissolved in the saliva as well as flavor
volatilized reaching the olfactory neuroepithelium). Due to the
fact that flavor perception is generally described as a combination
of taste and smell, the overall yield of a flavor is very difficult
to predict even if appropriate headspace sampling techniques (i.e.,
static or dynamic headspace sampling) are used. In fact, the most
straightforward approach is through evaluation by an olfactive
panel. Panel evaluations can be carried out directly with the
desired consumer product and do not require complex analytical
methods. If a sufficient number of panelists is used, the
statistical significance of the experiment can be determined.
[0118] An example of particle morphology is given in FIG. 20, which
reports optical microscopy pictures of the particles of Batch
SB10(5) (Table 5). Optical microscopy show a similar morphology for
the particles of the five scaled Batches. Pictures show a
capsule-like morphology that is likely obtained when oil is
encapsulated.
[0119] An evaluation of the five of methyl salicylate cetyl alcohol
microparticles of the scaled up Batches was conducted by a panel of
tobacco industry experts and was completely positive from the point
of view of flavor content and yield when mixed with snuff. The
particle size was considered optimal to avoid an oily taste in the
mouth as well an oily sensation in the hands.
[0120] Among the edible matrix materials that would be suitable for
use in the present invention are a wax, a fat, a fatty alcohol, a
sterol, cetyl alcohol, stearyl alcohol, paraffin, polyethylene
glycol, a fatty acid, a polyunsaturated fatty acid, rudua fatty
acid ester, palmitic acid, stearic acid, oleic acid, lauric acid,
myristic acid, behenic acid, a triglyceride, polyethylene glycol,
cholesterol, lecithin, a phospholipids, and mixtures thereof.
[0121] Among the flavoring agents that would be suitable for use in
the present invention are a volatile oil, an essential oil, a
botanical extract, methyl salicylate, ethyl salicylate, cinnamic
acid, cinnamon oil, peppermint oil, spearmint oil, wintergreen oil,
acetaldehyde, acetoin, aconitic acid, anethole, benzaldehyde,
N-butyric acid, d- or l-carvone, cinnamaldehyde, citral, decanal,
diacetyl, ethyl acetate, ethyl butyrate, ethyl vanillin, eugenol,
geraniol, geranyl acetate, glycerol tributyrate, limonene,
linalool, linalyl acetate, 1-malic acid, methyl anthranilate,
3-methyl-3 phenyl glycidic acid ethyl ester, piperonal, vanillin,
citrus flavoring, berry flavoring, and mixtures thereof.
[0122] Among the suitable surfactants that would be suitable for
use in the present invention are an alcohol, a fatty alcohol, a
fatty acid, a fatty acid ester, polyvinyl alcohol, polyethylene
glycol, alginic acid, a phospholipid, lecithin, cholic acid,
desoxycholic acid, diacetyl tartaric acid esters of mono- and
diglycerides, glycocholic acid, mono- and diglycerides and their
monosodium phosphate derivatives, propylene glycol, ox bile
extract, taurocholic acid, gum arabic, agar-agar, ammonium
alginate, calcium alginate, carob bean gum, chondrus extract,
ghatti gum, guar gum, potassium alginate, sodium alginate,
sterculia gum, tragacanth, hydroxypropylmethylcellulose, any other
water soluble derivatives of cellulose, and mixtures thereof.\
* * * * *