WHMF121 Session Twelve Fluid Extracts and Glycetracts (http://www.henriettesherb.com/files/styles/large/public/images/old/k ings/kings-percolator.jpg?itok=2xo5r1ps) Endeavour College of Natural Health endeavour.edu.au 1
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 2
Photo source: London Pharmacy Interior Wellcome Library Endeavour College of Natural Health endeavour.edu.au 3
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 4
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 5
Process of Percolation 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. Endeavour College of Natural Health endeavour.edu.au 6
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 7
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 8
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 9
Simple Percolation o 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 10
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 11
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 12
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 13
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 14
Video - Percolation o Please watch the video on herbal percolation: http://youtu.be/hvx0bl09hpe Endeavour College of Natural Health endeavour.edu.au 15
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 16
Fluid Extract of Echinacea purpurea 1:4 in 45% alcohol An 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 17
FE of Echinacea purpurea 1:2 in 45% alcohol Follow 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 18
Native to Northern America Whole plant is used Therapeutic Actions: Immuno modulator Antiseptic Antimicorbial Alterative Wound healing Echinacea purpurea Widely used by Naturopaths for a broad range of conditions E. angostifolia & E. pallida are also used therapeutically at times blended (Photograph with permission - Wendy Williams) Endeavour College of Natural Health endeavour.edu.au 19
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 20
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 21
Ensuring Quality o o o o o o o o Start with good quality raw material. Harvest and store under ideal conditions. Comminute herb to optimal particle size. Extract using most effective method and solvent. Standardise for marker constituents. Ensure stability of extract sealed systems used in manufacturing and proper storage conditions after manufacture. Use organoleptic testing. Conduct clinical trials to assess efficacy. Endeavour College of Natural Health endeavour.edu.au 22
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 23
o Is chemically an alcohol 1,2,3-propane triol. Glycerine (glycerol) 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 24
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 25
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 26
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 27
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 28
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 29
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 30
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 31
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 32
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 33
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 34
Glycetract by Reserve Percolation Method 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 35
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 36
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 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. Check on the tinctures from last week Endeavour College of Natural Health endeavour.edu.au 37
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 38
Suggested Readings British Herbal Medicine Association. (1996). British herbal pharmacopoeia (4 th ed.). Bristol, UK: British Herbal Medicine Association. Fenner, B. (1888). Fenner s complete formulary and hand-book (6 th 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 39
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 40
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