Fluid Extracts and Glycetracts · Coarsely ground herb is divided into 3-5 equal portions. ......

© 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)


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.


Photo source: ‘London Pharmacy Interior” Wellcome Library


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.


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.


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



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)



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.


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.


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.


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.


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.


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.


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.


Video - Percolation

o Please watch the video on herbal percolation:

http://youtu.be/hVx0BL09HPE

http://youtu.be/hVx0BL09HPE


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.


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


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.


• 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)


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.


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.


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.


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.


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.


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.


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.


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.


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.


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.


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.


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


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).


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.


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.


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.


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.


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


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


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.

https://archive.org/details/fennerscompletef00fenn


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.


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Fluid Extracts and Glycetracts · Coarsely ground herb is divided into 3-5 equal portions. ......

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