© Endeavour College of Natural Health endeavour.edu.au 1
WHMF121
Session Twelve
Fluid Extracts
and
Glycetracts
(http://www.henriettes-
herb.com/files/styles/large/public/images/old/k
ings/kings-percolator.jpg?itok=2XO5R1Ps)
© Endeavour College of Natural Health endeavour.edu.au 2
Today’s Topic
o Fluid extracts
o Percolation processes
o Multiple macerations
o Glycetracts
o Definitions, advantages and disadvantages of
these delivery methods as a dosage form
o Prepare some macerations under lecturer
supervision.
© Endeavour College of Natural Health endeavour.edu.au 3
Photo source: ‘London Pharmacy Interior” Wellcome Library
© Endeavour College of Natural Health endeavour.edu.au 4
Fluid Extracts
o Fluid extracts are made to a concentration of 1:1.
1:2, 2: or even 50:1.
o Tinctures are weaker than this (1:3, 1:4,1:5 up to
1:10).
o The extraction processes used to make liquid
extracts is more complicated than those used to
make tinctures.
o On a small scale, it is possible to make liquid
extracts by simple reduction or multiple
maceration.
© Endeavour College of Natural Health endeavour.edu.au 5
Fluid Extracts
o In a commercial situation percolation (cold) is the most efficient method of extraction.
o The percolation may be hot or cold.
o Hot percolation increases the loss of heat sensitive constituents.
o Reserve percolation, fractional percolation or repercolation and simple reduction are also methods used to concentrate the extract.
© Endeavour College of Natural Health endeavour.edu.au 6
1.Reduce the herb to a suitable particle size (i.e.
coarse powder).
This process is called comminution.
If it is powdered too finely the menstruum may not
filter through evenly and the percolation may clog.
However the larger the particle size the less
efficient the extraction.
Process of Percolation
© Endeavour College of Natural Health endeavour.edu.au 7
Process of Percolation
2. Macerate the herb in menstruum in a closed container for
4 hours to allow the herb to absorb the menstruum and
swell before it is packed into the percolator.
This process is called imbibition.
Not doing this could cut flow through the percolator upon
addition of the menstruum.
3. Pack the moistened herb into the percolator in stages.
Tap down gently after each addition of herb to
ensure uniform packing.
Percolation procedure and apparatus as used in Kings American Dispensatory (1898)
© Endeavour College of Natural Health endeavour.edu.au 8
Process of Percolation
4. Add enough menstruum to cover the herb.
When the menstruum starts to drip through the bottom
tap, close it off and macerate for 24-48 hours.
5. After 24-48 hours open the tap to allow a drip rate of
10-50 drips per minute to collect in a closed
collecting vessel.
6. The resultant extract (or percolate) is collected until
there is about ¾ of the final desired volume, and then
dealt with in a number of ways.
© Endeavour College of Natural Health endeavour.edu.au 9
Simple Percolation
1. The percolate is collected and the marc (remaining
herb) pressed.
2. The liquid pressed out of the marc is added to the
percolate that has been collected and the volume
measured.
3. If combined volume is less than the final desired volume
more menstruum is percolated through the herb until the
final volume is obtained.
© Endeavour College of Natural Health endeavour.edu.au 10
Simple Percolationo The final volume is determined by the strength of the
extract.
If 1kg of herb is being extracted, then a 1:5 tincture
would require 5 L of extract to be produced
o This method does not use any heat, so the constituents
in the resulting extract remain maximum activity.
The only drawback is that some plant constituents are
optimally extracted at higher temperatures.
© Endeavour College of Natural Health endeavour.edu.au 11
Reserve Percolation
1. The percolate that has been collected (3/4 of the final
volume) is put aside (reserved) and the herb is
“exhausted” with additional menstruum.
Exhaustion refers to the point when the menstruum
dripping through the herb is colourless and
odourless. This suggests there are no more
constituents to be extracted from the plant material.
2. The exhaust percolate is then concentrated by heat
(evaporation or distillation) until it is the volume needed
(with the reserve percolate) to make up the final volume
i.e., ¼ of the final volume.
© Endeavour College of Natural Health endeavour.edu.au 12
Reserve Percolation
3. The reserve and concentrated exhaust percolate are
added together to make the final volume of fluid extract.
o The problem with this method of extraction
is that the use of heat to concentrate the
exhaust percolate means that many heat
sensitive constituents are damaged.
© Endeavour College of Natural Health endeavour.edu.au 13
Repercolation
1. Coarsely ground herb is divided into 3-5 equal portions.
The first portion is percolated to the required finished
volume.
2. The second portion of herb is then percolated with the
menstruum collected from the first percolation.
3. The third portion of herb is then percolated with the
menstruum collected from the second percolation and so
on.
4. Thus the constituents are concentrated within the correct
volume of menstruum.
© Endeavour College of Natural Health endeavour.edu.au 14
Repercolation
o This method is time consuming but does not use any heat.
o Fractional percolation is a similar process but the portions
of herb are not equal and the menstruum is also divided
into portions.
© Endeavour College of Natural Health endeavour.edu.au 15
Video - Percolation
o Please watch the video on herbal percolation:
http://youtu.be/hVx0BL09HPE
© Endeavour College of Natural Health endeavour.edu.au 16
Multiple Maceration
o This process involves making a tincture, then using that
tincture as the menstruum to macerate another lot of herb.
o In this way the constituents from two lots of herb are
concentrated in one volume of extract.
o The procedure itself is quite simple (it just takes time), but
it can be difficult to get adequate coverage of herb with
menstruum if the herb is bulky or fluffy and not well
ground.
© Endeavour College of Natural Health endeavour.edu.au 17
Fluid Extract of Echinacea purpurea
1:4 in 45% alcoholAn ongoing class project:
1. Make a 1:4 tincture:
• Macerating 250g of ground, dried Echinacea purpurea
aerial parts in 1 litre of menstruum (45% alcohol, i.e..
550ml water and 450ml ethanol)
2. After two weeks:
• Strain off the extract and press the marc to recover as
much liquid as possible
• This will be used as the menstruum for the second
maceration.
3. We will continue to monitor this maceration and do the
next maceration over the coming weeks
© Endeavour College of Natural Health endeavour.edu.au 18
FE of Echinacea purpurea
1:2 in 45% alcoholFollow up for class project: - (to do in week 8)
1. Measure the volume of pressed liquid:
• Usually about 2/3 of the menstruum is recovered this depends on how well the marc can be pressed.
2. Supposing we recover 700ml of 1:4 tincture - we need to add another 175g Echinacea (175:700 = 1:4)
3. Prepare the fresh macerate, mix it with the measured off first menstrum, place in a jar and monitor for the next 2 weeks then press, strain, filter and bottle (remember for week 10)
4. By repeating the maceration process we effectively double the strength of the 1:4 tincture, making it a 1:2 fluid extract.
© Endeavour College of Natural Health endeavour.edu.au 19
• Native to Northern America
• Whole plant is used
• Therapeutic Actions:
• Immuno modulator
• Antiseptic
• Antimicorbial
• Alterative
• Wound healing
• Widely used by Naturopaths for a
broad range of conditions
• E. angostifolia & E. pallida are also
used therapeutically – at times
blended
Echinacea purpurea
(Photograph with permission - Wendy Williams)
© Endeavour College of Natural Health endeavour.edu.au 20
Fluid Extract: Simple Reduction
Method
1. The herb is infused or decocted in 20 times the
volume of water (1:20).
2. The resulting extract is simmered to evaporate the
water until it is reduced to ¾ of the final volume.
3. Pure alcohol is added to make it up to the final
volume.
4. The result is a 1:1 or 1:2 liquid extract (depending on
the final volume achieved) with 25% alcohol.
e.g. 500g herb is decocted in 10 Lts of water, reduced
over heat to 750ml, then 250ml alcohol added to
make 1Lt of a 1:2 extract.
© Endeavour College of Natural Health endeavour.edu.au 21
Simple Reduction Method
o The heat applied in reducing the infusion or decoction means that the extracts made in this way may effectively be weaker than a 1:5 tincture.
o Some exceptions apply as not all herbs are adversely affected by heat.
© Endeavour College of Natural Health endeavour.edu.au 22
Ensuring Quality
o Start with good quality raw material.
o Harvest and store under ideal conditions.
o Comminute herb to optimal particle size.
o Extract using most effective method and solvent.
o Standardise for marker constituents.
o Ensure stability of extract – sealed systems used in
manufacturing and proper storage conditions after
manufacture.
o Use organoleptic testing.
o Conduct clinical trials to assess efficacy.
© Endeavour College of Natural Health endeavour.edu.au 23
Glycetracts
o A glycetract or fluid-glycerate is a glycerine based
extract.
o Glycerine is a thick, colourless, sweet tasting liquid.
o Glycetracts were traditionally made to a strength of
1:1 by percolation using a glycerine solvent.
o Nowadays many herbs are made into glycetracts and
used by herbalists who want to avoid the use of
alcohol or to improve compliance because of the
taste factor.
© Endeavour College of Natural Health endeavour.edu.au 24
Glycerine (glycerol)
o Is chemically an alcohol– 1,2,3-propane triol.
o Made from the hydrolysis of animal and vegetable fats, or synthesised.
o Extracts made with glycerine are called Glycetracts.
o Glycerine extracts include tannins, gums, mucilages and alkaloids.
Glycerine is a sugar alcohol that is sweet
tasting, viscous and of low toxicity.
The 3 hydroxyl groups account for glycerine
being hygroscopic and soluble in water.
© Endeavour College of Natural Health endeavour.edu.au 25
Advantages of Glycerine
o Is non-toxic in normal doses.
o Quite nutritious and has a laxative effect when taken orally (used in suppositories for this action).
o Acts as a preservative if at a concentration of 60-70%
o Is hygroscopic, i.e. attracts moisture and therefore can be used as a drawing agent or to keep preparations moist.
o Has a slightly emollient and demulcent action so may be a useful addition to douches and gargles, or lotions and creams.
© Endeavour College of Natural Health endeavour.edu.au 26
Disadvantages of Glycerine
o Not as efficient as alcohol for extraction
o Less stable than alcohol – doesn’t preserve as well
o Inert substance such as gums and starches dissolve in glycerine.
o At high doses it causes dehydration with accompanying headache, thirst, nausea and hyperglycaemia in diabetics.
o It has a sweet taste which improves the taste of herbs, but is processed in the body as fat not a sugar.
© Endeavour College of Natural Health endeavour.edu.au 27
Disadvantages of Glycerine
o It is not volatile so doesn’t evaporate, but this means it
cannot be concentrated by heat.
o Will not extract oily or resinous constituents in plants
o Glycetracts are generally not as potent as fluid
extracts because alcohol is a better solvent than
glycerine
o Heat used in the manufacture of glycetracts may
inactivate certain constituents.
© Endeavour College of Natural Health endeavour.edu.au 28
Glycetracts
o Mucilaginous herbs that are popular as glycetracts:
• Althaea officinalis – Marshmallow
• Echinacea purpurea - Echinacea
• Glycyrrhiza glabra – Licorice
• Plantago lanceolata – Ribwort / Plantain
• Silybum marianum – St Mary’s Thistle
• Zea mays – Corn silk
o The glycerine enhances the demulcent action of these
herbs.
o Glycetracts are also made at strengths other than 1:1 and
are most commonly made by the replacement method.
© Endeavour College of Natural Health endeavour.edu.au 29
Glycetracts - Advantages
Glycetracts are useful because glycerine has many
properties of its own:
o Its sweet taste makes glycetracts more palatable than fluid
extracts.
o Its syrupy consistency means that glycetracts and preparations
made from them are emollient and demulcent (soothing and
softening to skin and mucous membranes), and can have a
drawing action.
o Glycetracts can be used in suppositories because glycerine is
laxative and promotes peristalsis.
o The viscosity of glycerin means it is not washed away easily, an
advantage for throat paints and gargles.
© Endeavour College of Natural Health endeavour.edu.au 30
Traditional Manufacturing of Glycetracts
o Glycetracts can be made by percolation or maceration using a variety of additional solvents.
o Most commonly alcohol and water are used because glycerine is not a very efficient solvent for most constituents, and its viscosity can make it more difficult to use.
o This could also be done using vinegar to improve extraction.
o 1 part glycerine
o 1 part vinegar (apple cider vinegar)
o 2 parts water.
© Endeavour College of Natural Health endeavour.edu.au 31
Glycetract by Maceration
Ingredients:
o 480ml glycerin
o 320ml distilled water
o 200g coarsely ground dried herb.
Method:
o Stir well to completely mix herb into menstruum.
o Close container tightly and agitate frequently for 14 days.
o Rotate jar daily, whilst macerating
o Press out liquid, filter through coarse filter cloth and bottle
© Endeavour College of Natural Health endeavour.edu.au 32
Glycetract by Replacement
o This method of making glycetracts is used by industry
(commonly used in Olive leaf preparations).
o It starts with a fluid extract, using alcohol and water as the
solvents, then a percentage of the alcohol and water is
evaporated off by heating and replaced with glycerine.
o Theoretically this ensures the most efficient extraction of
constituents while conferring the benefits of a glycerine based
medicine.
o Unfortunately the heat necessary to reduce the alcohol and
water content may damage certain constituents (alcohol
evaporates at quite a low temperature around 78ºC, water
evaporates at 100ºC).
© Endeavour College of Natural Health endeavour.edu.au 33
Glycetract by Replacement
o Gently reduce the desired fluid extract by half (eg. reduce
500ml to 250ml)
o Return the extract to its original volume by adding
glycerine (i.e. add 250ml glycerine in the example
above).
o This results in a glycetract the same strength as the fluid
extract it is made from, with 50% glycerine content.
o It is commonly believed that 50% glycerin by volume is a
good preservative, 60-70% is more reliable, or 50%
glycerine plus 10-15% alcohol.
© Endeavour College of Natural Health endeavour.edu.au 34
Glycetract by Reserve Percolation
Reserve percolation using glycerin and water as the solvents:
o This method requires special equipment – a percolator.
o Similar to tincture and fluid extract via percolation however with glycerine instead of ethanol.
Method:1. Place 2 parts herb in 1 part glycerin and as much water as is
necessary to cover the herb (eg. For 1 kg of herb you would use 500ml glycerine and around 1 litre of water depending on the texture and absorption of the herb.)
2. Macerate in a covered vessel for 24 hours.3. Pack mixture into percolator and macerate for another 24 hours.4. Begin percolation and collect a volume equal to the amount of
glycerine used initially (i.e.1 part or 500ml in the example given above). Put this liquid aside.
5. Exhaust the herb using water only.
© Endeavour College of Natural Health endeavour.edu.au 35
Glycetract by Reserve PercolationMethod – continues…
6. Gently simmer the exhaust percolate until the volume has
reduced to 1 part (i.e.. 500ml in the example given above).
7. Mix the two percolates together (i.e. 500ml of reserve
percolate and 500ml of concentrated percolate making 1
litre of extract from 1 kg of dried herb. This makes a 1:1
glycetract).
8. The same procedure may be followed using ½ part glycerin
and ½ part vinegar (8% acetic acid) with water as the
solvents.
Vinegar improves the extraction of alkaloids which are not very
soluble in glycerine and water, so would be a useful addition for
alkaloid-containing plants.
© Endeavour College of Natural Health endeavour.edu.au 36
Thyme, Licorice and Marshmallow Glycetract
This can be used for a throat gargle or for dry coughs
Ingredients (per group):
• Thymus vulgaris folia 30g
• Glycyrrhiza glabra radix 14g
• Althaea officinalis radix 10g
• Glycerine 200mL
• Distilled water 100mL
• Ethanol (96%) 30mL
Procedure:
o Measure & prepare ingredients
o Place all ingredients in sealed glass jar
o Shake/rotate daily for 14 days
o Strain the liquid off, press the marc and filter
o Store in amber glass and label.
© Endeavour College of Natural Health endeavour.edu.au 37
Tutorial Session
Class activity:
Start off the double maceration /extract
with Echinacea spp.– see slide 17 & 18
This will continue in week 8 & 10.
Practical Session:
o Break into working groups
o Make Glycetract Throat Gargle
• The formula is sufficient for a group of 2-3 to make and have a
sample of the product to take home – should end up with 50-100
mls each depending on method of pressing.
o Check on the tinctures from last week
© Endeavour College of Natural Health endeavour.edu.au 38
Preparation for next week
o Read through your textbook pp. 57 - 59 in
preparation for the lecture.
o Read through your slides for Session 14 –
Infused Oils
© Endeavour College of Natural Health endeavour.edu.au 39
Suggested Readings
British Herbal Medicine Association. (1996). British herbal
pharmacopoeia (4th ed.). Bristol, UK: British Herbal Medicine
Association.
Fenner, B. (1888). Fenner’s complete formulary and hand-book (6th ed.).
New York, USA: B. Fenner. Retrieved from
https://archive.org/details/fennerscompletef00fenn
Green J. (2000). The herbal medicine-maker’s handbook: A home
manual (pp. 105-115). NY: Crossing Press.
© Endeavour College of Natural Health endeavour.edu.au 40
References
Adams, J., & Tan, E. (2006). Herbal manufacturing: How to make
medicines from plants. Melbourne, Australia: Northern
Melbourne Institute of TAFE.
Mills, S., & Bone, K. (2013). Principles and practice of phytotherapy.
London, UK: Churchill Livingstone.
© Endeavour College of Natural Health endeavour.edu.au 41
COMMONWEALTH OF AUSTRALIA
Copyright Regulations 1969
COMMONWEALTH OF AUSTRALIA
Copyright Regulations 1969
WARNING
This material has been reproduced and communicated to you by or on
behalf of the Australian College of Natural Medicine Pty Ltd (ACNM)
trading as Endeavour College of Natural Health, FIAFitnation, College
of Natural Beauty, Wellnation - Pursuant Part VB of the Copyright Act
1968 (the Act).
The material in this communication may be subject to copyright under
the Act. Any further reproduction or communication of this material by
you may be the subject of copyright protection under the Act.
Do not remove this notice.
Top Related