This presentation is meant for academic purpose only and it includes basic information of some fibres- Cotton Silk, Wool and Nylon.

1. FIBRES
Study of Fibers used in Pharmacy such as
Cotton, Silk, Wool and Nylon
Prepared by,
Dr. Preeti D. Verma
Lecturer, Department of Pharmacognosy
L. M. College of Pharmacy, Ahmedabad
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2. FIBRES
Fibres, used in surgical dressings, are obtained from plant, animal or are man-made.
CLASSIFICATION OF FIBRES
Natural fibres can be classified, according to their origin, into following classes:
1. The vegetable or cellulose-base:
It includes fibres such as Cotton, Flax and Jute.
2. The animal or protein-base:
It includes Wool and Silk.
3. Regenerated and synthetic fibres:
They are man-made and include Nylon, Terelene, Orlon, Viscose and Alginate fibres.
4. Mineral fibre:
It includes Asbestos.
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3. Plant Animal Man-made
Cotton
(Raw and
Adsorbent)
Flax
Jute
Silk
Wool
Synthetic Regenerated
Nylon
Orlon
Polythene
Terelene Acetate
Rayon
Viscose
Rayon
Lustered Delustered
Fibres
Mineral
AsbestosVegetable fibres
CLASSIFICATION OF FIBRES (Schematic)
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4. Vegetable fibres and regenerated cellulosic fibres:
They are cellulosic, therefore they can be distinguished from animal fibres by the following tests:
1. Molisch’s test (with α-napthol and H2SO4) Violet colour.
2. With chlor-zinc iodine or Iodine and H2SO4 Blue colour.
3. When ignited No foul smell.
Animal fibres:
They can be distinguished from vegetable fibres by the following tests:
1. When ignited Unpleasant smell.
2. In 5% KOH Soluble.
3. With Picric acid Stained permanently (Yellow colour).
4. With Millon’s reagent Yellow colour.
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5. COTTON
Cotton
Absorbent
(Cotton wool)
Non-Absorbent
(Raw Cotton)
Types of Cotton:
It of two types: Raw Cotton and Absorbent Cotton.
B.S. : The hairs covering the seeds of various species of Gossypium particularly Gossypium herbaceum Linn. and
their hybrids.
Family : Malvaceae.
G. S. : USA, Egypt, India, South America.
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Cultivation :
• Plants are herbaceous or woody according to the species.
• In warm climates, the plant is perennial, but it is always grown as annual due to its susceptibility to attack by insects.
• Soil: Sands and loams (rich alluvial deposits)
• Seeds are sown in rows 3 to 5 ft. apart.
• Seedling are thinned out from 1 to 2 ft. apart .
• Manure: Initially nitrogenous, and later on phosphatic.
• The Plant after flowering, bears fruits known as Capsules or “bolls”.
Collection & Preparation:
• After ripening, the fruits dehisce by 3 to 5 valves, exposing the seed which are covered with the trichomes.
• These are collected, dried & transferred to a “gin”, where the trichomes are separated from the seeds.
• The felted “lint” is made into bales by hydraulic pressure.
COTTON (continued)
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Preparation of cotton for surgical use:
• Absorbent cotton wool is made from cotton waste.
• It is processed to get rid of most of the impurities, followed by boiling with 5% solution of caustic soda for 15 hours at
a pressure of 1 to 3 atmospheres.
• It is then washed with water & treated with suitable bleaching agent.
• It is further washed with water, and treated with dil. HCl and again washed with water
• Then, it is dried & carded into Flat sheets and finally packed.
COTTON (continued)
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8. Morphological Characters:
Raw Cotton:
It consists of a mass of soft brownish filaments. Each filament may be upto 4 cm in length and contains many impurities like
colouring matter, wax and fatty material.
Absorbent cotton:
It is raw cotton which has been freed from seeds, treated with alkali to remove the fatty cuticle, bleached, washed and
separated to produce a fleecy mass of soft white filaments. It is reasonably free from leaf, shell, fibre, dust and foreign
matter, made from comber waste.
COTTON (continued)
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9. Microscopical Characters: (Fig. 1)
Each filament consists of flattened, twisted, tubular trichomes. The edges are rounded and the thickness of the trichome
wall appears as a thickened margin. The apex is rounded and occasionally solid.
Each trichome consists of a single cell, 2 to 4 cm in length and 15 to 20 μ in breadth.
COTTON (continued)
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Constituents:
Raw Cotton:
Cellulose (91%), Wax, Oil, Fat (0.4%), Protoplasm and other cell contents (0.6%) Moisture (7.8%), Ash (0.2%)
Purified Absorbent Cotton:
Almost pure cellulose, Moisture (6 to 7%), Ash (0.1 to 0.3%)
Physical test:
Absorbency test:
1g of cotton wool, compressed to a volume of about 20 ml and placed tightly by means of forceps on the surface of water
at about 20˚C :
Raw cotton Float on surface of water.
Absorbent cotton Sink or becomes saturated within 10 seconds.
COTTON (continued)
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11. Chemical tests:
1. Moisten few threads of cotton wool with alcohol and mount in water. Irrigate the preparation with ammoniacal solution of
copper oxide (cuoxam) under high power. Observe the slide.
Raw Cotton Develops balloon-like swellings separated
by ring- shaped constricting bands formed
by the cuticle. (Fig. 2)
Absorbent
Cotton
Swells uniformly and eventually dissolve.
(Fig. 3)
COTTON (continued)
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2. When the trichomes of raw cotton are soaked in aqueous ruthenium red (8 mg in 100 ml), the excess of reagent removed
and cuoxam added, the cuticle is stained red and can be seen shrinking back to form constricting bands, while the inner
layers of wall swell to form globular enlargements. This indicates that the cutin is distributed throughout the primary wall
which contains pectin substances.
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12. 3. Mount a few threads in following reagents and observe microscopically any change in appearance:
(a) Solution of 5% KOH Does not dissolve.
(b) 66% v/v H2SO4 Dissolve rapidly.
(c) Phloroglucinol and HCl No red colouration (due to absence of lignification).
(d) In HCl Insoluble.
4. Mount a few threads in saturated aqueous solution of picric acid and allow to stand. Irrigate with water and observe.
No permanent staining takes place (because protein is absent).
5. Soak a few threads in iodine water for few minutes. Remove excess fluid and add 66% v/v H2SO4. Cotton is stained blue
(due to presence of cellulose).
6. Warm a few threads on a slide with Millon’s reagent No red colour (due to absence of Protein).
7. Boil a few threads of cotton wool in water for 1 minute. Transfer to cold, fresh Shirlastain A and stir for 1 minute.
Wash thoroughly with water and dry. Observe the resulting staining of the cotton.
Raw cotton Pale dusty purple.
Absorbent cotton Lilac colour (light purple).
Warm
COTTON (continued)
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13. 8. Boil a few threads of cotton wool for 1 minute in water. Transfer to cold, fresh Shirlastain C and stir occasionally for 5
minutes. Wash thoroughly with water and dry. Observe the resulting staining of the cotton.
Raw cotton Mauve.
Absorbent cotton Greyish pink.
COTTON (continued)
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Uses:
• Pharmaceutically, as a filtering medium.
• In surgical dressings.
• As an insulating material.
• Absorbent Cotton absorbs blood, mucus, pus and prevents wounds from infections by bacteria.
Storage:
It should be stored in cool, at a moisture content below 9%.
Heat renders absorbent cotton non-absorbent.
Absorbent cotton should be wrapped in papers so as to prevent the dust and microbial contamination.
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14. WOOL
Animal wool, Animal fibre
Biological Source : It consists of the cleansed and washed hairs from the fleece of the sheep Ovis aries Linn.
Family : Bovidae.
G. S. : Great Britain, Australia, U.S.A., America and Russia.
Preparation:
• The hairs, forming the fleece, are removed from the sheep at shearing time.
• They are thoroughly cleansed from dirt and wool-grease by means of soap and alkali carbonates.
• It is then bleached with sulphur dioxide or hydrogen peroxide.
• It is washed again and dried by hot air.
Morphological Characters:
It occurs as a loosely felted mass of long, fleecy, lustrous hairs, pale brownish-yellow in colour and smooth to the
touch. The hairs are somewhat elastic and tend to cling together.
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15. Microscopical Examination:
Place a few hairs of wool on a microscope slide. Moisten with alcohol and mount in dilute glycerine. Examine
microscopically.
Microscopical Characters: (Fig. 4)
The hairs are subcylindrical, solid, 15 to 60 μ in width. Each hair exhibits a narrow medulla of polyhedral or rounded cells
containing nuclei, a wide cortex of spindle-shaped, flattened, nucleated cells and a cuticle and flattened, imbricated
epithelial cells without nuclei. The projecting edges of the epithelial cells are directed towards the apex of the hair and give
rise to the characteristic irregular transverse markings on the surface of the hair.
WOOL (continued)
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16. Chemical tests:
1. Mount in cuoxam solution Do not swell or dissolve, but a blue colouration is produced.
2. Mount in following reagents:
(a) 5% KOH solution Readily soluble.
(b) 66% v/v H2SO4 Not soluble.
(c) Phloroglucinol and HCl Not stained.
(d) In HCl Not soluble.
3. Mount in saturated aqueous solution of picric acid. Stained yellow.
Allow to stand for 30 minutes and wash.
WOOL (continued)
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Constituents:
• Wool consists almost entirely of a protein, Keratin (which contains the elements C, H, O, N and S).
• Moisture (10 to 16%)
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17. 4. Mount in Iodine water. Add 66% H2SO4 v/v. No blue colour.
5. Warm with Millon’s reagent Red colour (due to presence of protein).
6. Stain with Shirlastain A Bright golden yellow colour.
7. Stain with boiling Shirlastain A Bright Copper-brown colour.
8. Heat with dry soda limein a test tube. Odour of Ammonia.
9. Add a piece of wool to a boiling Black colour
mixture of equal parts of lead (due to presence of sulphur).
acetate and NaOH solution.
WOOL (continued)
Uses:
• Pharmaceutically, as a filtering medium.
• In surgical dressings. 17
Presentation prepared for educational purpose only

18. Biological Source : It is the prepared fibre from the cocoons [the cases in which silk worm larvae lie temporarily (Fig.5)] of
Bombyx mori Linn. and other species of Bombyx and Antheraea mylitta Drury and other species of Antheraea.
Family : Bombycidae and Saturnidae, respectively.
G. S. : France, Italy, Japan and China.
Preparation:
• Larvae of the silkworm produce silk fibroin fibres from the glands in their mouth.
• This fibroin gets united with a gum-like secretion and forms Cocoon.
• These Cocoons are not allowed to grow further into an insect, but are placed in warm water to loosen the gum.
• The ends of the threads from 2 to 6 cocoons are caught up and wound into a single thread.
Morphological Characters:
It occurs as very fine, smooth, elastic threads and is usually pale yellow in colour.
SILK
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19. Microscopical Examination:
Mount some threads of silk in lactophenol and examine microscopically.
Microscopical Characters: (Fig. 6)
The threads are solid, homogenous, smooth or finely longitudinally striated, 5 to 60 μ in thickness. In the transverse section,
the threads are rounded or triangular with rounded corners.
SILK (continued)
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20. Chemical tests:
1. Mount in Cuoxam solution Silk is soluble.
2. Mount in following reagents:
(a) 5% KOH Slowly soluble.
(b) 66% v/v H2SO4 Soluble.
(c) Phloroglucinol and HCl No red colour.
(d) In HCl Rapidly soluble.
3. Mount in saturated aqueous solution of picric acid. Permanent yellow colour.
Allow to stand and wash.
4. Soak in Iodine water. Remove excess of liquid. Add 66% H2SO4 v/v. No blue colour.
Warm
SILK (continued)
Constituents:
Silk contains chiefly a protein Fibroin (which contains C, H, O and N, but no S).
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21. 5. Warm with Millon’s reagent Red colour (due to presence of protein).
6. Stain with Shirlastain A Slightly brownish-orange colour.
7. Burn a little silk Odour of NH3 produced and the smoke is alkaline to litmus.
8. Add piece of silk to a boiling mixture of equal parts of lead acetate and NaOH solution. No Black colour
SILK (continued)
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Uses:
Pharmaceutically, for making ligatures, oiled silk & certain types of sieves.
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22. NYLON
It is the polycondensation product of adipic acid and hexamethylene diamine fibres.
Morphological characters:
The filaments are smooth, solid cylinders. They may be any diameter. The polymer is highly lustrous to dull white or
coloured. It may be delustered or dyed. The filaments are very strong.
Microscopical Examination:
Mount some threads of silk in lactophenol and examine microscopically.
Microscopical Characters: (Fig. 7)
They show a uniform circular transverse section.
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Constituents:
Nylon is a polyamide. Long chain molecule of nylon structurally resembles silk.
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23. Chemical tests:
1. When ignited or applied to flame Melts and form hard bead and burns
2. In 5N HCl Soluble
3. In 90% formic acid Soluble
4. In 90% phenol Soluble
5. In 80% v/v sulphuric acid Soluble
6. In Acetone Insoluble
NYLON (continued)
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Uses:
• For preparing filter clothes, sieves & non-absorbable sutures. Nylon syringes are also prepared.
• In the preparation of polyamide which has great applications in chromatography.
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24. REFERENCES
• Study Pharmacognosy-II, Ms. B. K. Shah, Dr. N. S. Kapadia, Dr. R. D. Dangar, Ms. P. D. Verma, Nirav & Roopal
Prakashan , 1st Edition, 2011-12
• Textbook of Practical Pharmacognosy, Brian E. Hebert & Kenneth W. Ellery, 1st Edition, 1948.
• Shah and Qadry’s Pharmacognosy, Dr. J. S. Qadry, B. S. Shah Prakashan,, 14th Edition, 2008-2009.
• Textbook of Practical Pharmacognosy,, T. E. Wallis, CBS Publishers & Distributors, 5th Edition, 2004.
• Pharmacognosy & Phytochemistry, Vol.- I , 2nd Edition, Vinod D. Rangari, Career Publications, 2008.
• Textbook of Pharmacognosy & Phytochemistry, E. Edwin Jarald & Sheeja Edwin Jarald, CBS Publishers &
Distributors, Reprint 2009.
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25. Thank
You
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