U.S. patent application number 15/289503 was filed with the patent office on 2017-02-02 for preparation of stabilized catalase enzymes using polyvinyl alcohol.
The applicant listed for this patent is Avent, Inc.. Invention is credited to Bhalchandra M. Karandikar, Sunita J. Macwana, Zhongju Liu Zhao.
Application Number | 20170027839 15/289503 |
Document ID | / |
Family ID | 51388388 |
Filed Date | 2017-02-02 |
United States Patent
Application |
20170027839 |
Kind Code |
A1 |
Karandikar; Bhalchandra M. ;
et al. |
February 2, 2017 |
Preparation of Stabilized Catalase Enzymes Using Polyvinyl
Alcohol
Abstract
There is provided a method of producing a stabilized catalase
enzyme. In the method, a substrate is thoroughly mixed with
phosphate borate and catalase, rinsed with water and the solids
dried. The dried solid may be mixed with polyvinyl alcohol and
dried for further stabilization. The stabilized powder may be mixed
with various skin solutions (lotions, ointments and the like). The
catalase enzyme can catalyze the reaction of peroxide to
oxygen.
Inventors: |
Karandikar; Bhalchandra M.;
(Beaverton, OR) ; Macwana; Sunita J.; (Tigard,
OR) ; Zhao; Zhongju Liu; (Sherwood, OR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Avent, Inc. |
Alpharetta |
GA |
US |
|
|
Family ID: |
51388388 |
Appl. No.: |
15/289503 |
Filed: |
October 10, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14186143 |
Feb 21, 2014 |
9487759 |
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15289503 |
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61769395 |
Feb 26, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 2800/74 20130101;
A61Q 19/00 20130101; A61K 8/66 20130101; A61K 2800/56 20130101;
A61Q 19/08 20130101; C12N 9/96 20130101; C12N 11/12 20130101; C12Y
111/01006 20130101; A61K 8/8129 20130101; A61K 8/731 20130101; C12N
9/0065 20130101; C12N 9/0006 20130101; A61K 2800/52 20130101 |
International
Class: |
A61K 8/66 20060101
A61K008/66; A61Q 19/08 20060101 A61Q019/08; A61K 8/81 20060101
A61K008/81; A61K 8/73 20060101 A61K008/73; C12N 9/08 20060101
C12N009/08; C12N 11/12 20060101 C12N011/12 |
Claims
1-5. (canceled)
6. A microcrystalline cellulose adsorbed with a catalase enzyme and
further comprising polyvinyl alcohol, wherein the catalase enzyme
adsorbed on the microcrystalline cellulose with the polyvinyl
alcohol exhibits a decreased loss in catalase activity compared to
a catalase enzyme not adsorbed on the substrate with the polyvinyl
alcohol, wherein the catalase enzyme adsorbed on the
microcrystalline cellulose with the polyvinyl alcohol has an
activity at 25.degree. C. between 500 IU/g, and 1,000,000 IU/g, and
wherein the catalase enzyme adsorbed on the microcrystalline
cellulose with the polyvinyl alcohol is stable for up to 16 weeks
at 35.degree. C. after thermal cycling at 40.degree. C. for 72
hours and 55.degree. C. for 6 hours.
7. A skin hydrator lotion comprising lotion and the
microcrystalline cellulose of claim 6.
8. (canceled)
9. The microcrystalline cellulose of claim 6, wherein the ratio of
the microcrystalline cellulose to the catalase enzyme adsorbed on
the microcrystalline cellulose is between 1 and 10.
10. The microcrystalline cellulose of claim 6, wherein the catalase
enzyme adsorbed on the microcrystalline cellulose with the
polyvinyl alcohol includes manganese atoms.
11. The microcrystalline cellulose of claim 6, wherein the catalase
enzyme adsorbed on the microcrystalline cellulose with the
polyvinyl alcohol has a molecular weight of less than 500,000
Daltons.
12. The microcrystalline cellulose of claim 6, wherein the catalase
enzyme adsorbed on the microcrystalline cellulose with the
polyvinyl alcohol is derived from fungus.
13. The microcrystalline cellulose of claim 12, wherein the fungus
is Aspergillus niger.
14. The microcrystalline cellulose of claim 6, wherein the
polyvinyl alcohol has a molecular weight between 85,000 and 124,000
Daltons.
15. The microcrystalline cellulose of claim 6, wherein the catalase
enzyme adsorbed on the microcrystalline cellulose with the
polyvinyl alcohol can decompose from above 60% to 91% hydrogen
peroxide after thermal cycling when the ratio of the catalase
enzyme to hydrogen peroxide is 1:1.
16. The microcrystalline cellulose of claim 6, wherein the
microcrystalline cellulose further comprises phosphate and borate.
Description
[0001] This application claims priority from U.S. provisional
patent applications 61/664,251 filed on Jun. 26, 2012 and from
61/769,395 filed Feb. 26, 2013, respectively.
BACKGROUND
[0002] The present disclosure relates to a method of stabilizing
catalase enzymes for longer term storage and stability until use.
This disclosure also relates to the stabilized enzymes.
[0003] Oxygen is essential to sustaining life. Marine life utilize
oxygen in dissolved form whereas land based species including
humans utilize gaseous oxygen. The lack of oxygen or hypoxia is
commonly experienced by people in their extremities (e.g. feet) as
they get older due to poor blood circulation as well as by those
with conditions such as diabetes. Studies have also shown below
normal, low oxygen tension in the skins of older people. This often
leads to poor skin health and an excessive presence of visible
conditions such as wrinkles, dryness and lower skin elasticity.
Over the years, cosmetic manufacturers have introduced skin
formulations with a large variety of ingredients such as
emollients, exfoliators, moisturizers etc., to retard these age
related effects and improve and maintain skin health. Few
formulations have focused on the direct delivery of oxygen to the
skin.
[0004] Oxygen delivery to the skin has been examined for medical
use, e.g. in treating of the compromised skin (wounds, inflammation
and trauma) and more recently, intact skin. For example, Ladizinsky
patented an oxygen generating wound dressing (U.S. Pat. No.
5,792,090). More recently, Gibbins et al. patented a method of
making an oxygen generating foam dressing based on a polyacrylate
polymer (U.S. Pat. No. 7,160,553). While the method of making an
oxygen generating foam dressing is straightforward, the dressing
itself suffers from a few drawbacks. For instance, the shelf life
of the dressing is insufficient because oxygen from the dressing
diffuses out of the foam cells over time. An alternative to the
foam dressing in the form of an on-demand oxygen generating topical
composition was proposed to overcome the limitation of the short
shelf life (Ladizinsky US2009/0074880). In the '880 publication, a
gel containing a catalyst and a peroxide in a separate reservoir,
are brought together immediately before applying the mixture to the
skin and covering it to maintain contact with the skin. Whether
used for cosmetic applications or medical applications, oxygen
generation is generally achieved though the catalytic decomposition
of a peroxide, commonly hydrogen peroxide.
[0005] In any of the applications using catalyst and peroxide, a
problem that has been found is that the catalyst can become
inactivated during storage in a short period of time. Elevated
temperatures accelerate this inactivation for many catalysts. For
modern shipping and customer usage, it is important that the
product be stable for a period of time sufficient to package, ship,
market and sell it and to be stable in the user's home or other
location. The stabilization of peroxide and/or a catalyst in a
composition would be a step forward that would allow long term
storage of the product. It would also be desirable if the product
were stable at elevated temperatures commonly found in the shipping
industry.
[0006] There is a need for a way of stabilizing a catalyst and/or
peroxide for extended periods of time and at elevated temperatures.
This would allow for the production, packaging, storage and
shipping of a product without the product becoming deactivated
before the customer was able to use it.
SUMMARY
[0007] There is provided a way of stabilizing a catalyst,
particularly catalase, so that it may remain stable for an extended
period of time. There is also provided a way of stabilizing a
catalyst at elevated temperatures.
[0008] In the method, a substrate such as cellulose is thoroughly
mixed with phosphate borate and catalase, rinsed with water and the
solids dried. The dried solid may be mixed with polyvinyl alcohol
and dried for further stabilization. The stabilized powder may be
mixed with various skin solutions (lotions, ointments and the
like). The catalase enzyme can catalyze the reaction of peroxide to
oxygen.
DETAILED DESCRIPTION
[0009] Described below are methods of stabilizing catalase so that
it may be stored without becoming deactivated. Catalase, an enzyme
commonly produced by bacteria and fungi, can be used as a catalyst
to decompose peroxide to oxygen. This decomposition is extremely
rapid, but does depend on having a sufficient amount of catalase
for a given amount of peroxide in order to be successful. Catalase
can easily become inactivated over time so stabilizing the catalase
can extent its useful lifetime and improve its commercial
viability. Stabilization at higher temperatures is also important
since temperatures experienced during shipping can be high enough
to inactivate many catalysts.
[0010] The following procedure is a commonly accepted method of
measuring catalase activity that is used to determine how well the
catalase maintains its activity after stabilization and storage.
After that are examples of the preparation of the disclosed
stabilized catalase. Note that although the examples use
microcrystalline cellulose as the substrate, any suitable substrate
may be used, including ceramics and metals.
Analyzing for Catalase Activity
[0011] The activity of catalase enzyme is defined in International
Units (IU). A solution or solid powder (in suspension) is defined
to have an activity of one IU/ml or g if it can decompose 1
micromole of hydrogen peroxide per ml per minute at 25 C and pH 7.
During the analysis for catalase activity, the hydrogen peroxide
concentration is preferably maintained between 10 and 50 mM.
[0012] The analytical procedure for measuring catalase activity is
straightforward and is known to those of ordinary skill in the
enzyme industry. Briefly, following the addition of catalase
solution of unknown concentration to the hydrogen peroxide
solution, the peroxide absorbance value at 240 nm is monitored over
time using a UV visible spectrophotometer. Since the optical
density is linearly related to peroxide concentration, using the
absorbance versus time data, the concentration of peroxide versus
time data is obtained. Note that the molar extinction coefficient
of hydrogen peroxide at 240 nm is 39.4 liter/mol-cm. From the
kinetic data, the initial rate (at time 0) is obtained and used to
calculate the catalase activity.
Example 1 (Comparative)
Preparation of Cellulose Coated with Catalase with Poly Vinyl
Alcohol (PVA) (CCP) Over-Coat (Non-Adsorption Method)
[0013] We report on a bench scale preparation method for cellulose
catalase composite over-coated with PVA (hereafter referred to as
CCP) that did not involve a prolonged adsorption step. The
rationale was to learn if one could make robust CCP in a rapid
manner; something that is commercially always desirable.
[0014] Briefly, microcrystalline cellulose powder (6.0 g,
Avicel.RTM. PC 105 from FMC Biopolymer) was placed in a petri-dish.
To the cellulose, a sufficient amount of catalase solution (Grade
1500L, Activity: 50,000 IU/ml from BIO-CAT Inc. of Troy, Va.) was
added for a target theoretical activity of CCP of .about.10,000
IU/g. After swirling the slurry in the petri-dish for 15 minutes,
the dish was placed in a vacuum chamber to remove moisture and dry
the powder. Periodically, the weight of the petri-dish was checked.
When no change in its weight was observed, the vacuum was
discontinued. The dish was re-weighed and yielded .about.5.98 g of
CCP powder. The activity of CCP was found to be 2922 IU/g (See the
general description of catalase activity measurement).
[0015] In the next step, sufficient quantity of 2.4% w/w PVA
solution (PVA 98+% hydrolyzed, MW: 85K-124K from Sigma Aldrich) was
added to the CCP corresponding to a PVA/cellulose mass ratio of
0.02. Once again, the slurry in the petri-dish was swirled for 15
minutes. Thereafter, the dish was returned to the vacuum chamber
for removal of the solvent. When no change in the dish weight was
observed (it took several hours), the vacuum was discontinued.
[0016] The dry CCP was scraped off the dish surface and transferred
to a vial and stored at 4 C. The activity of CCP was measured to be
527 IU/g. Thus, following PVA coating and drying there was
significant loss of activity of CCP.
[0017] To understand the aging effect, dry samples of CCP powder
were maintained at 4 C, 25 C and 40 C for 1 week and then their
activities were re-measured. At 25 C and 40 C, the values were 344
IU/g and 99 IU/g respectively registering 35% and 81% loss. At 4 C,
the measured value of 441 IU/g indicated a loss of 16%. From the
activity results, it is obvious that simply preparing CCP by simply
blending respective ingredients and then drying the resulting mix
did not yield a robust CCP prototype.
Example 2
Preparation of Cellulose Powder Adsorbed with Catalase Over-Coated
with PVA
[0018] Rather than merely mixing catalase, cellulose powder and
PVA, here we describe a method of preparing microcrystalline
cellulose powder adsorbed with catalase enzyme and then over-coated
with a thin coating of PVA for protection (CCP-A). The method is
identical to making CCP as disclosed in Example 1 with the
exception of how the catalase is applied to the cellulose
powder.
[0019] In an empty pre-weighed conical bottom polypropylene (PP)
tube (from BD Falcon), a weighed quantity (0.5 g) of
microcrystalline powder (Avicel.RTM. PC105) was added. This
addition was followed by 4.5 ml phosphate borate buffer (0.05M, pH:
6.7) and 0.5 ml diluted catalase solution having an activity of
5000 U/ml. The diluted solution was prepared from a catalase stock
solution (Grade 1500 L grade) having an activity of .about.50,000
U/ml. The contents were briefly mixed on a vortex mixer and the
tube was placed on a shaker set at 800 rpm for 24 hours.
[0020] After 24 h, the liquid from the tube was drained and the
solids were rinsed three times using 5 ml de-ionized water each
time. After each rinse, the liquid was discarded. After the third
rinse, 1 ml of 1% w/w PVA solution was added to the wet cellulose
solids in the tube and the contents were mixed uniformly on a
vortex mixer. The resulting suspension was poured into a
petri-dish. Any remaining cellulose in the tube was re-suspended by
adding 2 ml de-ionized water and the suspension was transferred to
the petri-dish.
[0021] The liquid in the petri-dish was allowed to air dry
overnight at room temperature overnight inside a ventilated hood.
The dry CCP-A powder was gently scraped of the dish surface with a
blunt knife and weighed (0.4 g). The yield of CCP-A on cellulose
weight basis was .about.80%.
[0022] In this example a number of catalase activity measurements
were carried out. First, the catalase activity for wet cellulose
was measured (2282 U/g). Second, after drying, the activity of
resulting CCP-A was measured at 1980 U/g. This is about a 13% loss
in activity upon drying but this still was considered reasonable
when compared with the results seen in Example 1.
Example 3
Preparation of Skin Hydrator Blend with CCP-A @ 500 IU/g
Activity
[0023] The objective of this test was to (i) prepare CCP-A sample,
(ii) blend the CCP-A into Skin Hydrator lotion and (iii) subject
the Skin Hydrator blend with CCP-A to thermal cycling (to simulate
shipping transit) followed by accelerated age testing corresponding
to a 2 years shelf life. The Skin Hydrator used herein is formula
1553-07 from Benchmark Laboratories of Fountain Valley, Calif.,
though it is believed that this procedure can be used with
virtually any skin lotion, ointment or the like.
Preparation of CCP-A Powder
[0024] The following ingredients were added to a 15 ml PP conical
tube and placed on a shaker at room temperature to effect
adsorption of catalase on cellulose.
TABLE-US-00001 Microcrystalline cellulose 0.55 g BIO-CAT 1500 L
1.67 ml Phosphate buffer 3.33 ml
[0025] After the adsorption step, a procedure identical to that in
Example 2 was followed to obtain CCP-A powder. In all, four batches
were made and after pooling the batches yielded roughly 2.5 g of
powder. Based on cellulose, the yield was >100% but this was the
result of moisture, about 10%, that was present even after
prolonged drying. Because the powder obtained was free flowing, it
was used without further processing in the next step. The catalase
activity of the pooled sample of CCP-A was measured at 5103
IU/g.
Preparation of Skin Hydrator Blend with CCP-A
[0026] Dry CCP-A powder (1.5 g) was blended into Skin Hydrator
lotion (13.5 g) at 10% w/w loading to obtain starting catalase
activity of .about.500 IU/g in the sample. Because of the
difficulty of measuring catalase activity in the lotion, the
presence of catalase was confirmed indirectly by quantifying the
decomposition of hydrogen peroxide after mixing it with O2
Reservoir lotion 1574-06 from Benchmark in 1:1 ratio. Freshly made
Skin Hydrator lotion with catalase decomposed 100% peroxide in
slightly more than 5 minutes. (The pass criterion was a minimum of
60% decomposition after 20 minutes.)
Thermal Cycling and Accelerated Aging of Skin Hydrator Lotion with
CCP-A at 500 IU/g Activity
[0027] Abbreviated thermal cycling was used because the cold
condition (-20 C) was of no consequence as catalase is known to
degrade at temperatures above 37 C. In the abbreviated thermal
cycling, the lotion sample was aged at 40 C for 72 h followed by 55
C for 6 h. Next, the sample was placed in an oven set to 35 C and
monitored for its efficacy to decompose peroxide over 16 weeks for
accelerated aging. As a cosmetic industry norm, aging a product at
35 C for 16 weeks is considered a reasonable estimate of 2 years of
real time shelf life. A second sample that served as control was
maintained at room temperature (.about.25 C).
[0028] The table below shows the percentage peroxide decomposition
values over 16 weeks. Note not all values are >60% which was set
as the pass criterion. Nonetheless they are close to 60% within
experimental error. Thus, we can conclude that Skin Hydrator lotion
sample with CCP-A has demonstrated ability to withstand shipping
transit and has met the two year shelf life criterion.
TABLE-US-00002 TABLE 1 Accelerated Aging Test Results of Skin
Hydrator Lotion Samples CCP- A @ 500 IU/g After Thermal Cycling @40
C/72h and 55 C/6h Sample Wk Wk Wk Wk Wk Wk Wk Wk Wk ID Temp Start
Wk 1 Wk 2 Wk 3 4 5 6 7 8 9 10 11 12 0191- RT 100% 69% 67% 65% 66%
66% ND 62% ND 60% ND 65% ND 66/500 IU 35C 100% 69% 65% 63% 62% 63%
ND 56% ND 55% ND 59% ND Sample ID Temp Wk13 Wk14 Wk15 Wk16 0191- RT
70% ND ND 65% 66/500 IU 35C 68% ND ND 64% ND-Not determined
Example 4
Preparation of Skin Hydrator Blend with CCP-A @ 1000 IU/g
Activity
[0029] CCP-A was prepared in a manner similar to the Example 3
except for the following changes.
TABLE-US-00003 Microcrystalline cellulose 2.00 g BIO-CAT 1500 L
2.00 ml Phosphate buffer 3.00 ml
The resulting CCP-A powder had an enzymatic activity of 21,000
IU/g.
[0030] A blend of Skin Hydrator with adsorbed catalase was prepared
by blending cellulose powder (1.0 g) into the base Skin Hydrator
lotion (19.0 g) giving a starting catalase activity of .about.1000
IU/g, twice the value for the samples in Example 3. The sample was
subjected to thermal cycling as in Example 3 and then thermally
aged at 35 C with an identical control sample maintained at 25 C.
As before, each week, the sample efficacy to decompose peroxide was
monitored for a period of 16 weeks. The results obtained as
percentage decomposition values are listed in the table below.
TABLE-US-00004 TABLE 2 Accelerated Aging Test Results of Skin
Hydrator Lotion Samples With CCP-A @ 1000 IU/g After Thermal
Cycling @40 C/72h and 55 C/6h Sample ID Temp Start Wk 1 Wk 2 Wk 3
Wk 4 Wk 5 Wk 6 Wk 7 Wk 8 Wk 9 Wk 10 Wk 11 Wk 12 0191- RT 100% 90%
85% 81% 86% 85% ND 87% ND 83% ND 85% ND 68/100 0 IU 35C 100% 90%
80% 79% 76% 76% ND 77% ND 80% ND 80% ND Sample ID Temp Wk13 Wk14
Wk15 Wk16 0191- RT 90% ND ND 91% 68/100 0 IU 35C 85% ND ND 91%
ND-Not determined
[0031] The results of peroxide decomposition for the entire
duration are consistently above 60% thus handily passing the set
criterion. Such outstanding stabilization effect on catalase in a
very hostile environment has never been demonstrated before to our
knowledge. Comparing the percentage decomposition results in
Examples 3 and 4, it seems one would choose to have the starting
catalase activity in a robust commercial Skin Hydrator lotion to be
somewhere between 500 and 1000 IU/g for a 2 year shelf life. It is
possible that the lotion sample in this Example could have
exhibited the same efficacy for peroxide decomposition beyond 16
weeks, though it was not tested. With such long shelf life the
present lotion prototype has already outperformed any known
catalase containing product currently on the market.
[0032] As illustrated by Examples 2-4 above, there is herein
provided a method of preparing stabilized microcrystalline
cellulose through the steps of thoroughly mixing microcrystalline
cellulose powder, phosphate borate and catalase enzyme to create a
mixture having solids and liquid. The liquid is then drained from
the mixture and the remaining solids are rinsed with water.
Generally speaking, the ratio of cellulose to borate or catalase
enzyme is between 1 and 10 and the ratio of borate to catalase
enzyme is between 0.5 and 10. The resulting enzyme has an activity
at 25 C between 500 IU/g and 1000,000 IU/g.
[0033] The examples also show that a dry, flowable powder
containing catalase may be made by the methods herein. Catalase is
known to be difficult to stabilize in a dry form so this straight
forward method provides an advancement to the art of catalyst
stabilization.
[0034] In addition to the stabilization of catalase as described
herein, it has also been unexpectedly found that among the catalase
derived from different organisms, the one derived from a fungus,
Aspergillus niger, was most stable to thermal and chemical
environments encountered. The catalase in buffered solution, in the
adsorbed state on cellulose resisted degradation by heat or
chemicals ingredients in cosmetic compositions and retained the
necessary activity to produce compositions that survived rigorous
shipping protocols and prolonged ageing under heat to simulate
accelerated ageing.
[0035] Those ordinarily skilled in the art will recognize numerous
strains of fungus are commercially available, though a desirable
catalase source is fungus Aspergillus niger. It is important to
note that this disclosure encompasses catalase derived from any
source, including any fungal strain. The catalase molecules derived
from A. niger, however, have been known to contain manganese atoms.
Catalase may also be derived from genetically modified organisms
where the catalase producing vector may be derived from A. niger or
fungus in general and the host organisms in which the vector is
inserted may be a fungus or another organism. Thus, in a broader
aspect, the present disclosure encompasses catalase having
manganese atom or atoms within its molecular structure regardless
of which fungal or other organisms it is derived from. Catalase
with manganese atoms in its molecular structure and having
molecular weights <500,000 daltons are desirable.
* * * * *