DISCHARGE SOLIDIFIER AND MALODOUR CONTROL
The present invention relates to a superabsorbent and malodour control composition and in
particular, although not exclusively, to a superabsorbent for solidifying collected matter
excreted by the body and a control agent for controlling odours associated with the
excreted matter.
Ostomy patients typically wear an ostomy bag into which body waste is excreted. Ostomy
patients fall into three categories, each category necessitating the patient wearing an
ostomy bag. Firstly, urostomy patients typically have had their bladders removed.
Accordingly in this case, urine is passed through the stoma and into the ostomy bag.
Secondly, colostomy patients have undergone surgery to remove all or part of the colon
necessitating an ostomy bag to collect both liquid and solid excreted matter. Thirdly,
ileostomy patients similarly rely upon an ostomy bag to collect excreted matter which is
redirected through the abdominal wall.
Generally an ostomy bag comprises an opening which is sealed against the patient's skin
around the surgically created body orifice, termed a stoma. Many ostomy bags are
provided with a discharge outlet to allow excreted matter to be emptied from the ostomy
bag by the patient.
When body waste is excreted into the ostomy bag it continues to release malodours which
are unpleasant and can cause embarrassment to the patient. Also, where the excreted matter
is in liquid form, leakage from the ostomy bag is a potential risk which would also cause
embarrassment to the patient.
A number of additives have been proposed for ostomy bags designed to solidify excreted
fluid matter and reduce unpleasant malodours. US 2002/0055594 discloses a
superabsorbent tablet configured to thicken body excretions. The tablet comprises a
superabsorbent polymer in the form of cross linked sodium or calcium polyacrylate
designed to provide quick gelling of the ostomy bag contents following excretion.
US 6,852,100 also discloses an ostomy pouch configured to reduce unpleasant odours.
Superabsorbent fibres are used in combination with a malodour counteractant selected
from various different categories of odour controlling (masking and neutralising) agents
including for example hydrogen peroxide and bacterial growth inhibiters such as sodium
nitrate and benzyl alkonium chloride.
GB 2329339 discloses a superabsorbent for an ostomy bag comprising granules of a
superabsorbent formed into a stick or rod and housed within a water soluble outer sleeve.
Odour counteractants, disinfectants and preservatives are also incorporated within the
ostomy bag insert.
US 5,860,959 discloses a hydroscopic composition to reduce malodours from an ostomy
bag. Water absorbing materials such as starch or alkaline metal polyacrylates are employed
as superabsorbents in combination with odour counteractants such as volcanic clays and
activated carbon granules.
However, there exists a need for an ostomy bag insert configured to effectively solidify or
gel excreted matter and control unwanted malodours.
The inventors provide a superabsorbent material for positioning within a stoma bag
exhibiting superabsorbent and odour controlling properties. The superabsorbent blend has
been found to exhibit enhanced malodour reduction over existing ostomy bag inserts.
According to a first aspect of the present invention there is provided an ostomy bag insert
comprising: a polyacrylate superabsorbent; and a powdered zeolite; wherein the
superabsorbent is coated with the powdered zeolite.
Reference within the specification to zeolite includes zeolites being microporous and
capable of accommodating within their structure molecular species including ions and in
particular odorous compounds typically found in faecal waste.
Optionally, the zeolite may comprise a naturally sourced zeolite mineral including in
particular analcime, chabazite, clinoptilolite, heulandite, natrolite, phillipsite, and stilbite.
Optionally, the zeolite is a zeolite blend comprising a hydrophilic and a hydrophobic
zeolite. Alternatively, the zeolite may be substantially hydrophilic or substantially
hydrophobic. A preferred hydrophobic zeolite comprises an ammonium zeolite being a
zeolite having ammonium groups forming part of the zeolite structure. A preferred
hydrophilic zeolite comprises a sodium aluminosilicate.
Optionally, the insert may further comprise powdered activated carbon. Preferably the
insert comprises the zeolite as a major component and activated carbon as a minor
component based on a dry weight percentage. Optionally, a weight % ratio of the activated
carbon to the zeolite or zeolite blend, as part of the insert, is in the range 0.01:1 to 0.05:1.
The powdered zeolite may comprise a particle size equal to or less than 0.15 mm and/or
0.045 mm and/or 0.075 mm. Optionally, the zeolite comprises a surface area of
substantially 400 m /g.
Preferably, 99% by weight of the zeolite may comprise a particle size equal to or less than
0.15mm; 95% by weight of the zeolite may comprise a particle size equal to or less than
0.075 mm and 90% by weight of the zeolite may comprise a particle size equal to or less
than 0.045 mm.
Preferably, the activated carbon comprises and is derived from coconut shell char. The
activated carbon may comprise a surface area of substantially 1250 m /g. Preferably, the
polyacrylate superabsorbent comprises a granular configuration being at least one or a
multiple order of magnitude greater in size than the particle size of the zeolite or activated
carbon.
Synergistically, the zeolite and optionally the activated carbon may be bound to the
superabsorbent granules by electrostatic forces. The superabsorbent may comprise sodium
or calcium polyacrylate. Optionally, the zeolite and/or the activated carbon may comprise
any metal impregnated activated charcoal.
Preferably, the superabsorbent and powdered zeolite or zeolite blend is housed within a
water soluble paper sachet. The paper sachet may comprise sodium carboxy methyl
cellulose and wood pulp. The edges of the sachet may be heat sealed so as to trap the
granular superabsorbent and zeolite within the envelope formed by the soluble paper.
Alternatively, the zeolite or zeolite based blend may be encased within water soluble films
(e.g. PVA films), gel caps, plastic straws/wands or formed as tablets. Moreover, the insert
may comprise a plurality of separate units (e.g. tablets, gel caps, sachets). These units
would then be inserted separately into the ostomy bag.
According to a second aspect of the present invention there is provided an ostomy bag
comprising an insert as described herein. The insert may be permanently or temporarily
attached to an internal wall of the ostomy bag using conventional means found in the art.
For example, the insert may be attached to the internal walls via a flap, strap or permeable
pouch or cover allowing release of the superabsorbent and odour absorbing material upon
contact with the excreted body fluid.
Preferably, the insert comprises 1,000 mg to 10,000 mg of the polyacrylate superabsorbent
and 25 mg to 5,000 mg of the zeolite or zeolite blend.
A specific implementation of the invention will now be described by way of example only,
and with reference to the attached drawings in which:
Figure 1 illustrates an ostomy bag comprising an insert configured to solidify liquid matter
within the ostomy bag and control and reduce malodours according to a specific
implementation of the present invention;
Figure 2 illustrates a partial cut-away view of the ostomy bag insert of figure 1 formed as a
sachet containing a granular and powdered material;
Figure 3 illustrates a superabsorbent granule coated with a zeolite material;
Figure 4 is a GC chromatogram of solution 1- 3 mΐ/ml thioacetic acid and 0.5 mΐ/ml
ethanethiol in water;
Figure 5 is GC chromatogram of solution 2 - aqueous solution containing superabsorbent
polymer;
Figure 6 is a GC chromatogram of solution 3 - containing activated carbon;
Figure 7 is a GC chromatogram of solution 4 - containing activated carbon and
superabsorbent polymer;
Figure 8 is a GC chromatogram of solution 5 - containing zeolite blend;
Figure 9 is a GC chromatogram of solution 6 - containing zeolite blend and super
absorbent polymer;
Figure 10 is a GC chromatogram of solution 7 - containing hydrophobic zeolite;
Figure 11 is a GC chromatogram of solution 8 containing hydrophobic zeolite and super
absorbent polymer;
Figure 2 is a GC chromatogram of solution 9 containing hydrophilic zeolite;
Figure 13 is a GC chromatogram of solution 10 containing hydrophilic zeolite and
superabsorbent polymer;
Figure 14 is a GC chromatogram of solution 11 containing CW 90 Zn salt;
Figure 15 is a GC chromatogram of solution 12 containing CW 90 Zn salt and
superabsorbent polymer;
Figure 16 is a graph of the percentage decrease of ethanethiol and thioacetic acid peaks for
solutions 3 to 12;
Figure 17 is a graph of the percentage decrease of ethanethiol peak with increasing
absorbent compound concentration; and
Figure 18 is a graph of the percentage decrease of thioacetic acid peak with increasing
absorbent compound concentration.
The inventors provide a material blend configured to solidify excreted matter within an
ostomy bag and to reduce odours within the ostomy bag which would otherwise be
released from the bag when it is emptied by a patient. A material blend is housed within a
water soluble sachet which provides a convenient means by which the liquid and odour
absorbing material blend may be stored and transported prior to use within the ostomy bag.
The dissolvable sachet may be used in all manner of pouches or bags designed for
collecting body excretions such as ostomy, drainage bags or other applications where body
fluids require thickening or gelling and odour control (neutralisation/absorption).
Figure 1 illustrates an ostomy bag 100 comprising an internal chamber 105 and an inlet
opening 101 surrounded by an annular adhesive pad 102. A drainage flap 103 is provided
at a lower region 106 of bag 100. An odour controlling and liquid superabsorbent insert
104 is housed within internal chamber 105 and is dimensioned so as to pass through inlet
opening 101 during initial insertion prior to attachment of bag 100 and through outlet
opening 103 after empty and reuse of bag 100.
In use, ostomy bag 100 is secured to the skin of a patient at the abdominal region, via
adhesive pad 102 such that inlet opening 101 is aligned with the stoma site formed in the
patient. Accordingly, excreted matter passes through the stoma and into internal chamber
105 of ostomy bag 100 via inlet opening 101.
The excreted body fluid contacts insert 104 which acts to gel (partially solidify) the fluid
matter and control malodours within internal chamber 105.
Following solidification of the excreted matter, the contents of the ostomy bag 100 may
then be emptied via the flap arrangement 103 configured to dispense liquid and/or solid
from internal chamber 105. Flap 103 may comprise any conventional tap or flap design
configured to allow liquid and/or solid matter to be released from internal chamber 105.
Following emptying of the bag, a new insert may then be inserted into internal chamber
105 via the flap 103 such that a user is not required to detach bag 100 from positioning
around the stoma.
Referring to figures 2 and 3, insert 104 is formed as a sachet comprising a water soluble
paper having an upper layer 200 and a lower opposed layer 204. The edges of the upper
and lower layers 200, 204 are heat sealed 201 to define an internal cavity 202 sealed along
all four edges of the rectangular sachet. Insert 104 comprises liquid and odour absorbing
material blend 203 (comprising a polyacrylate based superabsorbent 300 and a powdered
zeolite 301) housed within internal cavity 202 formed by the upper and lower layers 200,
203. As will be appreciated by those skilled in the art, the present invention may comprise
any specific polyacrylate comprising superabsorbent properties suitable for use to absorb
fluids, excreted by the human body. The zeolite may comprise any natural or synthetic
zeolite or zeolite composite or blend configured to control malodours of the type
associated with human body excreted matter. It is preferred that the zeolite is a blend of a
hydrophobic and a hydrophilic zeolite,
Referring to figure 3, it has been found advantageous for malodour control/reduction to
coat the superabsorbent 300 with the zeolite 301. In particular, the superabsorbent,
according to a specific implementation of the present invention, is formed as granules or
pellets. In this configuration, the finely powdered zeolite readily coats the external surface
of the granules or pellets providing an active blend exhibiting enhanced odour control over
existing stoma bag inserts. The powdered zeolite may be maintained at the outer surface of
the superabsorbent granules by, in part, the electrostatic interactions between the
superabsorbent and the powdered zeolite.
According to one embodiment, the stoma bag insert 104 comprises a sodium polyacrylate
superabsorbent 300. The water soluble sachet comprises sodium carboxy methyl cellulose
and wood pulp comprising a thickness in a range 0.07 mm to 0.09 mm. The zeolite
comprises a zeolite blend having a hydrophilic zeolite component and a hydrophobic
zeolite component. The water soluble sachet comprises 2 g of sodium polyacrylate and
250 mg of zeolite.
According to a further specific embodiment, the insert 104 comprises sodium polyacrylate
superabsorbent 300, the same water soluble sachet as described above, a zeolite blend
having a hydrophilic and a hydrophobic component and powdered activated carbon.
EXPERIMENTAL INVESTIGATION
The effect of three odour absorbing compounds and a superabsorbent polymer on the
volatilisation of ethanethiol and thioacetic acid from aqueous solutions have been
investigated using GC headspace techniques.
It was found that all three of the odour absorbing compounds and the superabsorbent
polymer are effective (to a greater or lesser degree) at reducing the volatilisation of
ethanethiol and thioacetic acid from aqueous solutions at 37°C.
The most effective system for reducing the volatilisation of ethanethiol and thioacetic acid
from aqueous solutions at 37°C was found to be a hydrophilic/hydrophobic zeolite blend
combined with the superabsorbent polymer. This system showed around a 95% reduction
of the ethanethiol peak and 100% reduction of the thioacetic acid peak.
Results indicate that at 37°C and at concentrations of above 60mg/5ml the zeolite blend
combined with polymer has comparable effectiveness with carbon black and polymer at
suppressing the volatilisation of ethanethiol and thioacetic acid from aqueous solutions.
ANALYSIS
A GC headspace analysis method was developed during the course of the investigations
and used to quantify the levels of the odorous thiol compounds, thioacetic acid and
ethanethiol, in the headspace above aqueous samples, with and without the presence of
each of the absorbing compounds. The work found that two compounds - a zeolite blend
and CW90 Zn salt - gave results which were comparable to activated carbon. Both
compounds have the advantage over carbon black of being opaque/white, which should
enable easier examination of stoma bags containing the compounds.
The report below, details further investigations conducted into the absorption properties of
the hydrophobic and hydrophilic zeolites and the CW90 Zn salt at temperatures more
closely resembling body temperature and in the presence of a superabsorbent polymer.
OBJECTIVES
To test the capabilities of the zeolites and the CW90 Zn salt to absorb H2S, thioacetic acid,
ethanethiol and skatole both in pure aqueous solutions and in the presence of a
superabsorbent polymer.
METHOD
A stock solution of the odorous compounds H2S, thioacetic acid, ethanethiol and skatole
were made up at with 2 mg/ml in water. The samples were analysed using a Perkin Elmer
XL40 gas chromatograph with a Zebron ZB-624 capillary GC column (30m x .32 mm x
1.8u) with an FID detector.
No signals associated with H2S and skatole were observed using the method. H2S was not
detected by the FID detector and skatole was insoluble in water and its low volatility meant
that the concentration in the headspace at 40°C was negligible.
As a result, a second stock solution was prepared with 3 mΐ/ml thioacetic acid and 0.5 m /ml
ethanethiol in water only. 5ml of the stock solution was then added to each of the
following compounds:
Solution Odour absorbing Mass of compound Mass of superabsorbent
compound (mg) polymer (mg)
1 None 0 0
2 None 0 25
3 Activated Carbon 67 0
4 Activated Carbon 62 28
5 Zeolite Blend 62 0
6 Zeolite Blend 59 25
7 Zeolite Hydrophobic 60 0
8 Zeolite Hydrophobic 65 25
9 Zeolite Hydrophilic 60 0
10 Zeolite Hydrophilic 58 26
11 Cw90 Zn salt 60 0
12 Cw90 Zn salt 60 24
Table 1: Summary of the solutions prepared, detailing the odour absorbing compound
employed, its quantity and the quantity of superabsorbent polymer.
The GC analysis set up was as follows for all samples:
• Injection port temperature: 140°C;
• Carrier gas (H2) pressure 8psi;
• Oven program:
o 40°C isocratic for 5min;
o Ramp to 90°C at 10°C/min;
o isocratic at 90°C for 2 min;
• FID detector temperature: 240°C.
Headspace sampling was carried out as follows:
• Equilibrium time 7 minutes with shaking;
• Pressurisation 0.5 minutes;
• Injection 0.1 minutes;
• Withdrawal 0.1 minutes;
• Oven temperature 37°C;
• Needle 60°C;
• Transfer line 60°C.
BLANK RESULTS (SOLUTIONS 1+2)
Analysis of aqueous solution containing 3 mΐ/ml thioacetic acid and 0.5 mΐ/ml ethanethiol
resulted in peaks at ~2.5 minutes for ethanethiol and 5.75 minutes for thioacetic acid, the
results are shown in Figure 4
The same aqueous solution when added to 25mg of superabsorbent polymer showed that
the polymer itself had some odour absorbing qualities without the presence of any odour
absorbing compounds, as shown in Figure 5. The polymer was more effective at absorbing
thioacetic acid than ethanethiol.
SUMMARY OF RESULTS
EFFECT OF CONCENTRATION
The effect of the concentration of the absorbing compounds and the polymer on the level
of odours compound absorption were also investigated. 5 ml of the stock solution
containing ethanethiol and thioacetic acid was added to vials containing masses of odour
absorbing compounds ranging from ~20mg to ~150mg. The results are displayed in the
tables below. Note: all experiments on the absorbing compounds were performed in
aqueous solutions without polymer.
Activated Carbon:
Mass of compound Percentage decrease of Percentage decrease of
(mg) ethanethiol peak thioacetic acid peak
27 87 100
39 87 100
63 93 100
103 100 100
Zeolite Blend:
Zeolite Hydrophobic:
Zeolite Hydrophilic:
Cw 90Zn salt
Superabsorbent gel:
The performance of the absorbing compounds identified as solutions 3 to 12 are detailed in
figures 6 to 15 respectively.
A summary of the percentage decrease of the ethanethiol and thioacetic acid peaks for
solutions 1 to 12, based on the gas chromatography results of figures 4 to 15 are shown in
figure 16. The effect of the percentage decrease of the ethanthiol peak with increasing
absorbent compound concentration is illustrated in figure 17 and the percentage decrease
of thioacetic acid peak with increasing absorbent compound concentration is shown in
figure 18.
CONCLUSIONS
No signals associated with H2S or skatole were observed using the GC headspace method.
H2S was not detected by the FID detector and skatole was insoluble in water and its low
volatility meant that the concentration in the headspace at40°C was negligible.
All the odour absorbing compounds reduced the peak height of ethanethiol and thioacetic
acid compared to the blank, solution 1. The polymer also reduced the peak heights of
ethanethiol by 20% and thioacetic acid by 90%.
Almost all the odour absorbing compounds showed enhanced peak reduction of ethanethiol
and thioacetic acid with the presence of the superabsorbent polymer, the hydrophilic
zeolite was the only compound which showed little to no enhancement of ethanethiol
absorption by addition of polymer.
The present results indicate that the hydrophobic zeolite is more effective at reducing the
ethanethiol peak than the thioacetic acid peak, whilst the hydrophilic zeolite shows the
opposite effect and is much less effective at reducing ethanethiol, but effective at reducing
the thioacetic acid peak.
The Zeolite blend containing both hydrophilic and hydrophobic forms (solution 5)
absorbed more ethanethiol and thioacetic acid than the individual zeolites themselves.
The Zeolite blend (solution 6) combined with the superabsorbent polymer appears to be the
most effective system for reducing the volatilisation of ethanethiol and thioacetic acid from
aqueous solutions at 37°C. The solution showed ~ 95% reduction of the ethanethiol peak
and 100% reduction of the thioacetic acid peak. The blend was successful because the
hydrophobic zeolite had a greater effect on the absorption of ethanethiol and the
hydrophilic zeolite a greater effect on the absorption of thioacetic acid.
At ~37°C the performances of the zeolite blend and activated carbon appear to be roughly
comparable. Activated carbon is more effective at the lower concentrations (~20mg in 5ml)
at reducing the volatilisation of ethanethiol and thioacetic acid, but at higher concentrations
(-60-1 OOmg) the zeolite blend performs equally as well.
Cw 90 Zn salt was the least effective of the three compounds tested and showed only
minor reductions on the levels of ethanethiol. Reductions in the thioacetic acid peak height
were observed. At higher concentrations, in aqueous solutions, the Cw 90 Zn salt performs
relatively well suppressing both the ethanethiol and thioacetic acid peaks. However, in the
presence of the polymer it performed less well, possibly indicating an inhibiting effect of
the polymer on the salt's performance.
Generally, increasing the concentration of the odour absorbing compound decreased the
volatilisation of ethanethiol and thioacetic acid. The exception was the hydrophilic zeolite,
which reached a plateau of ethanethiol reduction at -20%.

Claims
1. An ostomy bag insert comprising:
a polyacrylate superabsorbent; and
a powdered zeolite;
wherein the superabsorbent is coated with the powdered zeolite.
2. The insert as claimed in claim 1 wherein the powdered zeolite comprises a
particle size equal to or less than 0.15 mm.
3. The insert as claimed in claims 1 and 2 wherein the zeolite comprises a particle
size equal to or less than 0.075 mm.
4. The insert as claimed in any preceding claim wherein the zeolite comprises a
particle size of equal to or less than 0.045 mm.
5. The insert as claimed in any preceding claim wherein the zeolite is a zeolite blend
comprising a hydrophilic zeolite and a hydrophobic zeolite.
6. The insert as claimed in claim 5 wherein the hydrophobic zeolite is an
ammonium zeolite and the hydrophilic zeolite is a sodium aluminosilicate.
7. The insert are claimed in claim 1 wherein the zeolite comprises a surface area of
substantially 400 m /g.
8. The insert as claimed in any preceding claim further comprising powdered
activated carbon.
9. The insert as claimed in claim 8 wherein a weight % ratio of the activated carbon
to the zeolite as part of the insert is in the range 0.01:1 to 0.05:1.
10. The insert as claimed in any preceding claim wherein the polyacrylate
superabsorbent is granular.
11. The insert as claimed in any preceding claim wherein the superabsorbent
comprises sodium or calcium polyacrylate.
1 . The insert as claimed in any preceding claim comprising a water soluble paper
formed as a sachet to house the superabsorbent and the zeolite.
13. The insert as claimed in any one of claims 1 to 11 comprising a water soluble film
to house the superabsorbent and the zeolite.
14. The insert as claimed in any one of claims 1 to 11 comprising a gel cap to house
the superabsorbent and the zeolite.
15. The insert as claimed in any one of claims 1 to 11 comprising a plastic
straw/wand to house the superabsorbent and the zeolite.
16. The insert as claimed in any one of claims 1 to 11 wherein the insert is formed as
a soluble tablet.
17. The insert as claimed in any preceding claim comprising 1,000 mg to 10,000 mg
of polyacrylate superabsorbent.
18. The insert as claimed in any preceding claim comprising 25 mg to 5,000 mg of the
powdered zeolite.
19. The insert as claimed in any preceding claim comprising a metallic salt
impregnated zeolite.
20. An ostomy bag comprising an insert as claimed in any preceding claim.