Note: Descriptions are shown in the official language in which they were submitted.
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COATING AND EXTRUDING METHOD FOR
PRODUCING STARCH SOFTGEL CAPSULES
FIELD OF INVENTION
[0001]
This invention relates to a preparation method of softgel
capsules, more specifically, of non-gelatin softgel capsules.
BACKGROUND OF THE INVENTION
[0002]
Softgel capsules are generally used for enclosing medicines
that should not directly contact esophagus and that must be
disintegrated in the stomach or intestine.
At present, most
capsules used for medicine or dietary supplements are made of gelatin
extracted from animal skins or bones, and the gelatin extracting
process involves acid or alkali treatment, which unavoidably
generates animal protein residues. These residues will interact with
the enclosed content and thus leads to negative consequences such
as drug spoilage.
[0003]
In addition, animal-derived gelatin is not acceptable to
vegetarians and/or the people with Islamic and Jewish beliefs, and
those with allergic constitution should also avoid intake of gelatin
products.
[0004]
As starch is made from rich source of plants, its price is
far lower than that of gelatin. The starch, when modified, achieves
better gelation performance and mechanical strength, making its
characteristics close to that of gelatin. Since starch softgel
capsules will overcome the shortcomings of existing gelatin
capsules and at the same time, has the advantage of low cost, It is
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worthy of popularization.
[0005] Conventionally, the general practice is like this: Apply the
prepared gel solution onto the rollers, and then, after the solution
becomes glutinous coating due to partially moisture evaporation, send
it into the capsule machine for filling, pressing, and forming. In
this technology, however, we will have to pre-coat demoulding agent,
such as silicone, silicone oil, etc, on the roller and the mold or
add such agent to the gel solution formula due to the fact that the
coating is adhered to the roller and can hardly be released. This
will cause part of the releasing agent enter into the finished softgel
capsules and consequently result in unnecessary impurities in the
medicine.
[0006] On one hand, capsule shell must be quickly dissolved in the
stomach and intestines to release active substances and, to store
medicine, the capsule shell must be made of weldable material, so
as to ensure sufficient stability at the joint seam. On the other
hand, if the starch film lacks sufficient elasticity, it will be easily
torn, especially in the demoulding process, or lead to final capsule
tearing.
OBJECT OF THE INVENTION
[0007] It is therefore an object of the present invention to provide
an innovative coating-method for preparing starch softgel capsules,
the innovation of which lies in that, coating the gel on the
starch-based extrusion film----the basic framework of a capsule----,
to be more specific, on the side of encapsulation. As the starch
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extrusion film directly touched to the roller is not adhered to the
roller, no releasing agent is needed to separate it from the roller.
The softgel capsules prepared using this method remains no residue
of releasing agent, and thus significantly improves the safety level.
[0008] The invention discloses a preparation method of
starch softgel capsules, which includes the following 2 steps:
[0009] (a) Composite starch film preparation: Make
premixed
starch-based material into starch extrusion film by
extrusion mechanism, and then apply the gel solution coating to the
starch extrusion film to form the composite starch film.
[0010]
(b) Preparation of starch softgel capsules: Apply two pieces
of composite starch films to make starch-based softgel capsules using
rotary die process.
[0011] In the above steps:
[0012] The preparation method of the starch
extrusion
film includes the following steps: use double screw-type extruder
to extrude the starch based premixed material
into
starch granules, and then process the starch granules into
starch-based extrusion film using single screw-type extruder.
[0013]
The starch-based premixed material is prefabricated with
starch, anti-caking agent, and gelatinization agent
[0014] Coating method: Mix water retention agent, gel, and
emulsifier in water to prepare the gel solution and then coat this gel
solution onto the starch extrusion film to form composite starch
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film.
[0015] Description of Each Step:
[0016] (1) Mix the starch and anti-caking agent for 5 minutes in
a high-speed mixer at the speed of 1500-2000rpm and under the
temperature of 60 C, and then slowly add gelatinization into the
high-speed mixer while keep stirring for another 5 minutes.
[0017] (2) Feed the starch-based premix into a double-screw
extruder to make starch granules. Then process the granules into
starch-based extrusion films using single screw-type extruder.
[0018] (3) Prepare the gel solution by mixing water retention agent
and emulsifier in deionized water, and then apply the gel solution
coating to the inner side (the encapsulation side) of the
starch extrusion film to make composite starch film.
[0019] The starch mentioned in the above step 1 is native or modified
starch(modified by chemical or physical process), preferably,
esterified cassava starch.
[0020] The anti-caking agent mentioned in the above step 1 is
pharmaceutical stearic acid or
[0021] fatty glyceride
[0022] The gelatinization mentioned in the above step 1 is deionized
water.
[0023] The parameters of the double screw-type extruder mentioned
in the above step (2) are as follows: material temperature , 25-160
oC; screw rotation speed, 60-400 rpm; (optimized speed should be
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50-150 C, 60-140 C, 70-130 C, 80-140 C, 90-120 C, 100-1400C.)
[0024] The parameters of the single screw-type extruder mentioned
in the above step (2) are as follows: material temperature, 25-16000;
screw rotation speed, 60-400 rpm.
[0025] The gel mentioned in the above step (3) is one or a
combination of the substances selected from the group consisting of
amylopectin, gellan gum, carrageenan, xanthan gum, guar gum, sodium
alginate, and locust bean gum.
[0026] The water retention agent mentioned in the above step (3)
is pharmaceutical glycerin or pharmaceutical sorbitol.
[0027] The emulsifier mentioned in the above step (3) is an ionic
emulsifier, preferably pharmaceutical alkali metal sulfate or
alkali metal sulfonate, such as pharmaceutical sodium dodecyl
sulfonate or pharmaceutical sodium dodecyl sulfate.
[0028] The said gel solution consists of the following components:
[0029] Gel: 15%-25% of the gel solution (by weight);
[0030] Water retaining agent: 1-5 %( by weight); of the gel
solution
[0031] Emulsifier: 0.02-1% (by weight) of the gel solution;
[0032] deionized water.
[0033] Thickness of gel solution coating:
0.2-0.5 L gel solution
per square meters of starch based extrusion film.
[0034] Preparation of Starch-based softgel capsules
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[0035] Starch-based softgel capsules are prepared by rotary die
process, which is described as follows:
[0036] Feed two pieces of composite starch films into the two
adjoining cylinder moulds, with the gel-attached extrusion film
facing upwards; Adjust the mould temperature to 40-90 C and start
the machine. Then, the two cylinder moulds drive the two composite
films spinning inward in different direction. The grooves on the
mould can be vacuumed to make the composite starch films adhered to
the mould form pits, which is then extruded through the mould into
softgel capsules with cavity, while at the same time of the capsule
formation, the capsule content is filled from right above the
junction of the two cylinder moulds.
[0037] The starch-based softgel capsules prepared according to
this invention can be used for the preparation of drugs, health
products, and functional foods.
EXAMPLES
[0038] The examples set forth below further explain the contents
of this invention and the nature of products produced using this
invention. All the following examples are illustrative, and should
not be viewed as limiting the scope of the present invention.
[0039] Example 1
[0040] The raw materials used to prepare starch-based extrusion
film and their weight ratio:
[0041] Starch: corn starch, 75%;
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[0042] Anti-caking agent: pharmaceutical stearic acid, 1.2%;
[0043] Gelatinization agent: Deionized water, 23.8%;
[0044] The raw materials used to prepare the gel solution and their
weight ratio:
[0045] Gel: carrageenan, 25%
[0046] Water retaining agent: pharmaceutical glycerin, 1%
[0047] Emulsifier: pharmaceutical sodium dodecyl sulfate, 0.2%
[0048] Deionized water: 73.8%
[0049] The parameters of the double screw-type extruder are as
follows
[0050] Extrudes at the rotation speed of 350 RPM, and the designed
temperature for each slider are as follow
[0051] Slide 1: 25 C
[0052] Slide 2-3: 110 C
[0053] Slide 4-6: 145 C
[0054] Slide 7-9: 165 C
[0055] Slide 10-12: 160 C
[0056] Nozzle: 160 C
[0057] The parameters of the single screw-type extruder are as
follows
[0058] The rotation speed of the screw is 350 RPM, and the designed
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temperature, 105 C.
[0059] The Operation steps are as follows:
[0060] (a) Mix the starch and anti-caking agent in the high-speed
mixer for 2 minutes at the speed of 1500-2000rpm and under the
temperature of 60 C, then slowly adds gelatinization agent into the
high-speed mixer while keeps on stirring for another 5 minutes, the
starch-based premix is then ready.
[0061] (b) Input the starch-based premixed material into the double
screw-type extruder to extrude the premixed material into
starch granules, and then make the starch granules into starch-based
extrusion films using single screw-type extruder.
[0062] (c) Prepare the gel solution by dissolving water retention
agent and emulsifier in deionized water, and then apply the gel
solution coating to the inner side (the encapsulation side) of the
starch extrusion film to make composite starch film.
[0063] Starch-based capsules preparation: Put the composite starch
films into the rotary die with temperature control device to make
starch-based capsule. The die temperature is set at 60 C.
[0064] No releasing agent is added during the above
preparation processes.
[0065] Example 2
[0066] The raw materials used to prepare starch-based extrusion
film and their weight ratio:
[0067] Starch: starch, 75%;
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[0068] Anti-caking agent: pharmaceutical stearic acid, 1.2%;
[0069] Gelatinization agent: Deionized water, 23.8%;
[0070] The raw materials used to prepare the gel solution and their
weight ratio:
[0071] Gel: cross-linking cassava starch, 25%
[0072] Water retaining agent: pharmaceutical glycerin, 1%
[0073] Emulsifier: pharmaceutical sodium dodecyl sulfate, 0.2%
[0074] Deionized water: 73.8%
[0075] Other parameters and processes are the same as example 1. .
[0076] Example 3
[0077] The raw materials used to prepare starch-based extrusion
film and their weight ratio:
[0078] Starch: corn starch, 75%;
[0079] Anti-caking agent: pharmaceutical stearic acid, 1.2%;
[0080] Gelatinization agent: Deionized water, 23.8%;
[0081] The raw materials used to prepare the gel solution and their
weight ratio:
[0082] Gel: guar gum, 25%
[0083] Water retaining agent: pharmaceutical sorbitol, 1%
[0084] Emulsifier: pharmaceutical sodium dodecyl sulfate, 0.2%
[0085] Deionized water: 73.8%
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[0086] Other parameters and processes are the same as example 1.
[0087] Example 4
[0088] The raw materials used to prepare starch-based extrusion
film and their weight ratio:
[0089] Starch: esterified cassava starch, 75%;
[0090] Anti-caking agent: pharmaceutical stearic acid, 1.2%;
[0091] Gelatinization agent: Deionized water, 23.8%;
[0092] The raw materials used to prepare the gel solution and their
weight ratio:
[0093] Gel: carrageenan, 20%
[0094] Water retaining agent: pharmaceutical glycerin, 3%
[0095] Emulsifier: pharmaceutical sodium dodecyl sulfate, 0.2%
[0096] Deionized water: 76.8%
[0097] Other parameters and processes are the same as example 1.
[0098] Example 5
[0099] The raw materials used to prepare starch-based extrusion
film and their weight ratio:
[0100] Starch: mung bean starch, 75%;
[0101] Anti-caking agent: pharmaceutical stearic acid, 1.2%;
[0102] Gelatinization agent: Deionized water, 23.8%;
[0103] The raw materials used to prepare the gel solution and their
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weight ratio:
[0104] Gel: Xanthan gum, 25%
[0105] Water retaining agent: pharmaceutical glycerin, 1%
[0106] Emulsifier: pharmaceutical sodium dodecyl sulfate, 0.2%
[0107] Deionized water: 73.8%
[0108] Other parameters and processes are the same as example 1.
[0109] Example 6
[0110] The raw materials used to prepare starch-based extrusion
film and their weight ratio:
[0111] Starch: corn starch, 75%;
[0112] Anti-caking agent: pharmaceutical stearic acid, 2.2%;
[0113] Gelatinization agent: Deionized water, 22.8%;
[0114] The raw materials used to prepare the gel solution and their
weight ratio:
[0115] Gel: gellan gum, 25%
[0116] Water retaining agent: pharmaceutical sorbitol, 1%
[0117] Emulsifier: pharmaceutical sodium dodecyl sulfate, 0.2%
[0118] Deionized water: 73.8%
[0119] Other parameters and processes are the same as example 1.
[0120] Example 7
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[0121] The raw materials used to prepare starch-based extrusion
film and their weight ratio:
[0122] Starch: corn starch, 75%;
[0123] Anti-caking agent: pharmaceutical stearic acid, 2.2%;
[0124] Gelatinization agent: Deionized water, 22.8%;
[0125] The raw materials used to prepare the gel solution and their
weight ratio:
[0126] Gel: locust bean gum, 25%
[0127] Water retaining agent: pharmaceutical sorbitol, 1%
[0128] Emulsifier: pharmaceutical sodium dodecyl sulfate, 0.2%
[0129] Deionizer water: 73.8%
[0130] Other parameters and processes are the same as example 1.
[0131] Comparative Example
[0132] The raw material components and their weight ratios are the
same as that of example 3; and the preparation processes are as
follows:
[0133] Put all the above materials into the kettle, and then add
deionized water. Heats the water to 60 C and stir it till it is fully
dissolved and swelling; Keep the temperature for about 1 to 2 hours
till the solution is ready for use. Input the above premixed material
to the double screw-type extruder to extrude the premixed material
into starch granules, which are then made into starch-based extrusion
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films using single screw-type extruder.
[0134] Starch-based capsules preparation: Put the composite films
into the rotary die with temperature control device to make
starch-based capsule. The mold temperature is set at 60 C.
[0135] Add regular releasing agent like polyorganosiloxane or
methyl silicone oil in the preparation process.
[0136] Take 6 samples of capsules. Each sample is made up of certain
amount of capsules made by the method applied in one of the 6 examples;
inspect the breakage rate and finished product rate of the capsules
in each sample. (Refer to Table 1 for the result0 the results in table
1.
[0137] Film yield analysis: Demoulding 10000 pieces of films using
regular measure, and check the amount of torn and damaged films.
[0138] Damage inspection: Put 100 capsules in the friability tester,
rotate the tester 100 times, and count the number of damaged capsules.
[0139] The above comparative example shows that the performance
of the softgel capsules prepared according to this invention is
outstanding and complies with the standards of the Chinese
Pharmacopoeia. The product made by this invention maintains a
relatively high yield rate when no releasing agent is used; and an
unexpected finding is that when certain types of gels, like guar
gum ,xanthan gum, are used, the breakage rate of the product is far
lower than when releasing agent is applied. The welding material at
the joint seam of the capsule shell directly affects the welding
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stability. Proper welding material can avoid breakage and leakage
resulted from instable welding. The gel solution coating on the
starch film framework makes the welding point more stable.
Table 1
Starch film Capsule
Total broken
Breakage Broken
and damaged
Breakage rate
rate (%) capsules
pieces
Example 1 90 9.0 1 1
Example 2 91 9.1 2 2
Example 3 11 1.1 0 0
Example 4 78 7.8 1 1
Example 5 15 1.5 0 0
Example 6 87 8.7 2 2
Example 7 89 8.9 1 1
Comparative 93 9.3
9 9
example
[0140] According to the inspection regulations described in
appendix XA of Chinese Pharmacopoeia 2nd, the disintegration time
limit of the capsules made in the above example 1 to 7 is 1 hour.
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