HERBAL COSMETICS HERBAL DRUG TECHNOLOGY.
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HERBAL SKIN CARE PRODUCTS HERBAL HAIR CARE PRODUCTS HERBAL ORAL CARE PRODUCTS
HERBAL COSMETICS HERBAL DRUG TECHNOLOGY.
- 1. 1 HERBAL COSMETICS Miss Poonam Pardhi Assistant Professor Adarsh institute of Pharmacy, Nagpur
- 2. 2 According to Drug and cosmetic act, Cosmetics are defined as an articles intended to be rubbed, poured, sprinkled or sprayed on, introduced into or otherwise applied to the human body or any part of body for cleansing, beautifying, promoting attractiveness or altering the appearance. Herbal cosmetics are known as natural cosmetics. Herbal cosmetics are formulated by using different cosmetic constituents to form the base in which one or more ingredients of natural origin are used. The term Cosmeceuticals was first developed by Raymond Reed member of U.S. society of Cosmetics Chemist in 1961. The word cosmetic was derived from the Greek word "Kosm tikos" which means having the power or skilled in ordering or arranging
- 3. 3 Herbal cosmetics used in skin care have been formulated using the principles from the ancient texts of Rig Veda, Yajur Veda, and Ayurveda, Unani and Homeopathic systems of medicines. In herbal cosmetics, herbs are used either in crude form or as extracts. Herbs includes crude plant materials like leaves, flowers, fruit, seeds, stem, wood, bark, root, rhizome or other plant parts, which may be entire, fragmented or powdered. Herbal materials also included fresh juices, gums, fixed oils, essential oils, resins and dry powders of herbs. Herbal cosmetics should be the result of merging nature with modern technology
- 4. 4 In India, herbal cosmetics make up 10% of the total cosmetic industry that is estimated to be around 200 crores The current growth rate of Indian cosmetic industry is 20- 25% per year, of which herbal cosmetics alone make up for 60% Herbs do not produce immediate cures. They provide a way to make the body in proper tune with nature. An enormous number of cosmetics and toiletry formulations have been designed and developed which are based upon herbs. The demand of herbal medicines is increasing quickly due to their skin easiness and lack of side effects. The natural ingredients in the herbs also provides nutrients and minerals to body.
- 5. 5 Advantages of Herbal Cosmetics over Synthetic cosmetics Natural in nature Safe to use Compatible with body Variety of product Affordable and Non expensive Not need to tested on animals No OR less side effects
- 6. 6 Skin Care Products Herbal Creams: The key ingredients in the formulation of herbal creams are plant derivatives. Following are the important types of herbal creams: Cold Creams: Galen formulated the first herbal cold cream using beeswax, water, olive oil (as emollient), and rose petal (as fragrant). Cold creams are water-in-oil emulsion (w/o), and the bases used in their preparation are: a) Almond oil and white bees wax, and b) Borax (as emulsifier) and rose water. For example- Nyle cold cream.
- 7. 7 Vanishing Creams: These are oil-in-water emulsion (o/w), and are hardly visible when applied to skin. They impart moisturising as well as emollient effect. For example, jojoba vanishing cream. The common ingredients of vanishing cream are glycerine, stearic acid, triethanolamine, lanolin, natural jojoba extract, water, preservative, and perfume. Procedure- The waxy materials (stearic acid and lanolin) are melted together. The resultant mixture is added with water, jojoba extract, triethanolamine, and glycerine. Lastly, preservatives and perfumes are added to the mixture and stirred constantly so that a uniform mass can be obtained.
- 8. 8 Nourishing Creams: These creams are non-greasy, and provide nourishment as well as protection to the skin. For example, nourishing skin cream (Himalaya). Following ingredients are present in nourishing creams: a) Aloevera to nourish and moisturise the skin, b) Indian kino tree and ashwagandha to protect the skin from pollution and dry weather c) Gotu Kola to increase collagen production. d) Along with the above mentioned ingredients , nourishing creams also include liquid paraffin, glycerine, sodium EDTA, phenoxyethanol, methylparaben, etc., which act as formulation base.
- 9. 9 Night Creams: These creams are applied during night. They consist of revitalisers, moisturisers, and skin-rejuvenating nutrients. Night creams prevent evaporation and moisturise the skin. For example, revitalising night cream (Himalaya). For nourishment of skin, the following herbal agents are added in the night creams: a) Pyrus malus (Crab Apple) for cooling, soothing and keratolytic effect. b) Triticum sativum (Wheat) for preventing black heads. c) Citrus limon (Lemon) for protecting the skin from oxidative damage. d) Lilium polyphyllum (White Lily) for astringent effect. e) Solanum lycopersicum (Tomato) for its antioxidant effect.
- 10. 10 Moisturiser Creams: These creams are applied on dry skin as they heal and repair dry skin, and maintain the softness of skin. They maintain skin hydration by reduction evaporation. For example, aloe moisturising cream. Contain aloe vera gel, tocopherol (vitamin E), chamomile extract, beeswax, and coconut oil. Coconut oil is added to and melted with the heated beeswax. This molten mixture is stirred continuously and allowed to cool slowly. Aloe vera gel is added drop wise during the stirring process. When the mixture become s uniformly thick, stirring is stopped. Lastly, chamomile extract and vitamin oil are added
- 11. 11 Anti-Acne Creams: These creams are applied on the skin surface, and mainly act on hair follicles and sebaceous glands. For example, Himalaya acne and pimple cream. Following ingredients are present in anti-acne creams: a) Lens culinaris (Lentil) for reducing inflammation b) Silk cotton tree that acts as an astringent and emollient, and c) Vitex negundo that exhibits anti-inflammatory action
- 12. 12 Sunscreen Creams: These creams are used topically to protect the skin from harmful effects of sunrays. They act either by scattering the sunlight or by absorbing the erythematous rays of sun. Eg: Ayur sunscreen. Herbal sunscreen includes the following ingredients: a) Aloe vera, b) Fat-soluble walnut extract, c) Bees wax, and d) Hydrogenated ricinus oil.
- 13. 13 Fairness Creams: These creams reduce melanin formation as well as skin pigmentation. For example, Himalaya fairness cream. The main ingredients of fairness creams are: a) Rosa centifolia to improve complexion, b) Citrus reticulata as a blemish remover, and c) Aloe vera as a moisturiser and emollient.
- 14. 14 Herbal Powders: A range of powders are available in the market such as dusting powder, talcum powder, body powder, after-bath powder, after- shave powder, and baby powder. A minor difference exists among the formulation of talcum powder, dusting powder, after-shave powder, and baby powder. Therefore, these powders are considered same to some extent . Powders are dispensed through flat, oval, round or angular plastic or metal cans sometimes a puff is used so that powder can be applied easily. Generally powders have the following ingredients
- 15. 15 Talcum Powders a) Talc (71%), b) Potato starch (30%), c) Zinc stearate (3%), d) Boric acid (5%), e) Perfume (1%). Body Powders a) Talc (50%), b) Boric acid (2%), c) Precipitated chalk (17%), d) Perfume (1%). After-Shave Powders a) Talc (71%) b) Titanium dioxide (3%), c) Potato starch (4%), d) Precipitated chalk (20%), e) Golden ochre (0.5%), f) Perfume (1%) Baby Powders a) Talc (63.63%), b) Barley (20%), c) Zinc stearate (5%), d) Precipitated chalk (5%), e) Boric acid (6%), f) Oxyquinoline benzoate (0.12%), g) Perfume (0.25%).
- 16. 16 Herbal Face Washes: These are used to remove dirt, dust and other debris adhered to the facial skin. These preparations also have antiseptic as well as antimicrobial properties. Depending on the need and skin type of consumers, different types of face washes are formulated:
- 17. 17 Gentle Face Washes: These are used for mild cleansing and are applied very gently on the face. Daily use of these face washes protects the skin against dust, dirt, and pollutants. All Skin Type Face Washes: These are formulated without any soap , thus can be used on daily basis for almost all skin types.
- 18. 18 Herbal Face Packs: These formulations are applied on face to stimulate blood circulation in facial region, provide muscle toning, make the facial skin supple and elastic, and clean clogged skin pores by removing impurities. For example, neem face pack (Himalaya). Following are the ingredients commonly used in the formulation of herbal face packs
- 19. 19 Herbal Lip Balms These are used on lips to prevent them from cracking, chapping and drying. Edible ingredients should be used in the formulation of lip balms. They also contain ingredients that act as natural filter to UV rays and vitamin E to provide nourishment and softness. Following are the ingredients commonly used in the formulation of lip balms:
- 20. 20 Herbal Soaps: These are used for cleansing the body. The basic fatty acids used in the formulation of soaps are triglycerides such as tallow, coconut oil, or palm oil. Quality and properties of the soap depends on the proportions of fats and their combination used for their preparation. Soaps made up of tallow are harder than the soaps made up of coconut oil; while potassium soaps are softer than sodium soaps, but are rarely used. The properties of soaps can be enhanced by adding other ingredients, like opacifiers, emollients , and chelating agents.
- 21. 21 Hair Care Products Hair Gels: These are used for hair styling as they make hair manageable, easy to handle, and reduce their tendency to fly. For examples, Clove Hair Gel Preparations: These are prepared by heating benzoate lard. The remaining ingredients are mixed with this molten lard to form a cream with a pleasant fragrance and ability to set hair. Following are the ingredients commonly used in the formulation of clove hair gel preparations:
- 22. 22 Herbal Shampoos These are used for cleaning hair. Various herbal shampoos, containing a unique blend of natural ingredients, are available in the market as per the requirement of consumer s and type of hair. Examples, Methi-Shikakai Shampoos: These are powder-based shampoos as all the ingredients present are crushed, pulverised, and powdered. Two hours before using, this shampoo should be soaked in half cup of water. Following are the ingredients commonly used in the formulation of methi-shikakai shampoos:
- 23. 23 Herbal Hair Colours: These are used to cover-up grey hair or as a style statement. Herbal hair colours are prepared by boiling leaves of desirable herb in water. The resultant mixture is left undisturbed for a few hours, and then strained to remove the leaves. Lastly, alcohol and perfume are added. Pyrogallol and metallic salts are added to produce a range of colours with henna. But they may produce toxic effects if used on broken skin.
- 24. 24 Herbal Hair Conditioners These preparations are used to condition the hair by moisturising them properly. This problem can be overcome by using w/o emulsion as its aqueous component moisturises the hair and the lipid component locks the moisture and prevents evaporation. Wheat Hair Conditioners: These conditioners are prepared by mixing all the ingredients with the beaten egg. The resultant mixture is massaged on scalp, and washed after sometime with lukewarm water mixed with lemon juice Following are the ingredients commonly used in the formulation of wheat hair conditioners
- 25. 25 Herbal Hair Oils: These preparations provide nourishment to the scalp and hair roots, as well as impart a lustrous texture to hair . Herbal hair oils are prepared by the following procedure: Collection and Authentication of Plant: Leaves of bhringraj ( Eclipta alba), flowers of China rose ( Hibiscus rosa sinensis), and rhizomes of jatamansi ( Nardostachys jatamansi) are collected and dried in shade. These dried parts are pulverised, mixed , and filtered through sieve number 80. The pharmacognostic parameter of each drug should also be studied. Preparation of Herbal Hair Oil: To prepare herbal hair oil, 10%w/v of Eclipta alba and Hibiscus rosa sinensis and 5% w/v of Nardostachys jatamansi are boiled in one litre of coconut oil till the crude vegetable drug gets charred and attains black colour. The so obtained oil is filtered and stored in an airtight bottle.
- 26. 26 Oral Hygiene Products Toothpastes: These serve dual purpose; firstly, they remove stains from the teeth, and secondly, they freshen up breath and mouth. Traditional toothpastes are used for removing deposits (such as stains,plaque, etc.) from the teeth surface as they make the teeth appear dull Various toothpastes are available with different physical characters and dispensers. They are present as viscous liquids and pastes that can be extruded from inflatable tubes, as pastes that can be extruded from pumps, and as clear products (called gels) for enhancing their external appearance. Sparkles or soft plastic particles of various colours are also added in many types of toothpaste
- 27. 27 Tooth Powders: These are considered to be forerunner of toothpastes; however, they are now losing popularity. Tooth powders are mixtures of dental abrasives, flavouring agents, sweetening agents, and foaming agents. They are packed in containers having an orifice on top for sprinkling. The major disadvantage of toothpowders is that a calculated amount is difficult to obtain.
- 28. 28 Mouthwashes: These are flavoured liquids used for rinsing the oral cavity after brushing and flossing. Mouthwashes are used orally for maintaining dental hygiene. They mainly clean teeth, prevent tooth decay and gum diseases, and also freshen up the breath. An ideal mouthwash should have the following properties: It should be quick in action and potent enough to show its intended action at specific dilution. It should have a strong flavour to mask the foul smell of mouth. It should have an acceptable taste. Its production cost should be low. It should not irritate the oral cavity or mucous membrane. It should be non-toxic.
- 29. 29 Gargles: These are medicated aqueous preparations used for treating pharyngitis, laryngitis, and any other throat infections. Gargles are diluted before use. They should never be swallowed but should be spitted out after rinsing the oral cavity. Gargles are formulated using the following ingredients: Flavouring agents (eucalyptol, menthol, etc.) impart a distinct taste and flavour. Preservatives (sodium benzoate) inhibit and prevent microbial growth. Sweetening agenst (sodium saccharin and sucralose) provide acceptable taste. Water helps in liquefaction of all the ingredients. Colouring agents enhance the organoleptic property and increase the aesthetic value. Fluoride is added in a limited amount to strengthen the teeth and prevent mottling of teeth. Detergents provide cleansing action as they remove plaque and food particles adhered to the teeth. Calcium strengthens the teeth, and prevents tooth decay and mottling
- 30. 30 Sources & description of raw material used of herbal origin in herbal cosmetics Sources and description of the following raw materials of herbal origin used in formulating herbal cosmetics are discussed below: Fixed oils Waxes Colours Perfumes Protective agents Bleaching agents, Antioxidants Surfactants Preservatives
- 31. 31 FIXED OILS Oils are derived from vegetable and mineral sources, and are used in cosmetics. Examples of vegetable oils are almond oil, arachis oil, castor oil, olive oil, and coconut oil. Examples of mineral oils are light and heavy paraffin.
- 32. 32 COCONUT OIL It is obtained from the dried solid part of the endosperm of coconut, i.e., Cocos nucifera (family Palmae). It exists as a white or pearl white unctuous mass in winter and colourless in summer
- 33. 33 ALMOND OIL It is a fixed oil obtained by expressing the seeds of Prunus amygdalus (family Rosaceae). It is pale yellow in colour and has a characteristic odour. The active principles o f almond oil are the mixture of glycoside with oleic acid, linoleic acid, myristic acid, and palmitic acid. Due to its emollient action, it is used in the preparation of creams and lotions.
- 34. 34 ARACHIS OIL It is a fixed oil obtained from the seeds of Arachis hypogea (family Leguminosae). It is pale yellow in colour and has a faint nutty odour. Refined arachis oil is colourless, and its active principles include oleic acid, linoleic acid, and a small amount of other acids. At 3°C, it turns cloudy, and at a lower temperature, it solidifies. Arachis oil is used in the preparation of hair oils and brilliantines.
- 35. 35 CASTOR OIL It is obtained from the seeds of Ricinus communis (family Euphorbiaceae). It is either yellow in colour or colourless and has a slight odour. Castor oil consists of a mixture of glycosides, in which 80% of ricinoleic acid is the major constituent. At 0°C, it forms a clear liquid. Due to its emollient action, it is used in the preparation of lipsticks, hair oils, creams, and lotions.
- 36. 36 OLIVE OIL It is obtained from the fruits of Olea europea (family Oleaceae). It is either pale yellow or greenish yellow in colour, and has a slight odour. Olive oil consists of glycerides of oleic, palmitic, linoleic, stearic and myristic acids. At low temperature, it gets solidified or partially solidified. Due to its emollient action and soothing properties, it is used in the preparation of creams, lotions, and bath oils.
- 37. 37 LIQUID PARAFFIN: It consists of a mixture of hydrocarbons and appears as a colourless and odourless oily liquid. Its viscosity and weight per ml (0.83-0.87gm) ar e low. Due to its better spread ability, it is used in the preparation of bath oils, hair oils, lotions, and creams. HEAVY LIQUID PARAFFIN: It is obtained from petroleum. It is a mixture of hydrocarbons, and appears as a colourless and odourless oily liquid. Due to its soothing effect on the skin, it is used in the preparation of creams, lotions, hair oils, and bath oils.
- 38. 38 WAX Waxes are the esters formed by the condensation of high molecular weight straight chain fatty acids with high molecular weight straight chain monohydric alcohol of methanol series. They are used as a base in cosmetics, along with oils and fats. Some commonly used waxes are:
- 39. 39 BEESWAX It is a purified wax separated from the honeycomb of bees, Apis mellifera (family Apidae). It is composed of 70% myricyl palmitate ester. It is a yellowish brown coloured solid with honey-like odour. Under cold conditions, it turns brittle; and on bleaching, it becomes a yellowish-white solid with faint characteristic odour. Its melting point is 62-65°C. Beeswax helps in water incorporation to form an emulsion.
- 40. 40 CARNAUBA It is obtained from the leaves of the Brazilian wax palm, Copernica cerifera (family Palmae). It is available in various grades, with the highest grade existing as light-brown to pale-yellow in colour. It occurs as moderately coarse powder or flakes with a characteristic bland odour. Its melting point ranges from 81-86°C. Carnauba wax is hard and is used in the manufacture of candles, wax varnishes, and leather and furniture polishes.
- 41. 41 SPERMACETI It is a solid wax obtained from the head, blubber and ear case of the sperm whale, Physeter catodon (family Physeteridae). It consists of cetyl palmitate and cetyl myristate spermaceti in a solid wax, which is a translucent crystalline, pearly-white, unctuous mass with a slight odour and taste. It melts at a specific gravity of about 0.94. Spermaceti is also available synthetically and consists of a mixture of esters of saturated fatty alcohols and saturated fatty acids. Synthetic spermaceti occurs as white to off-white translucent flakes with a crystalline structure and a pearly lustre. Its melting point ranges from 43-47°C.
- 42. 42 PARAFFIN It is obtained by the distillation of petroleum. It is a mixture of solid hydrocarbons, mainly containing n-paraffins, and their isomers to some extent. Thus, it is also called hard paraffin wax . It is colourless, odourless, or a white, translucent, wax-like solid, and is slightly greasy to touch. Its melting point ranges from 50-57°C.
- 43. 43 COLOUR Humans are using colours in cosmetics since ancient times. The desire to buy a cosmetic product is controlled by three senses, i.e., sight, touch, and smell. Thus, colour is an important ingredient of cosmetic formulations. Some commonly used natural colours in cosmetics are:
- 44. 44 SAFFRON It is the stigmas and tops of the styles of the plant, Crocus sativus (family Iridaceae). It is a perennial plant grown in Jammu and Kashmir. Saffron powder is yellowish and easily soluble in water, thus is used as flavouring and colouring agent in food preparations. It consists of a few carotenoids, of which crocin is an important natural saffron carotenoid. Picrocrocin is a colourless bitter glycoside that imparts a characteristic odour to saffron.
- 45. 45 COCHINEAL It is a red dyestuff obtained from the dried female insect, Dactylopius coccus (family Coccidae). The main colouring constituent in cochineal is carminic acid, which forms red needles on crystallisation; these needles darken at 130°C and carbonise at 250°C. Cochineal is extracted with water, and alum is added to this solution to precipitate carmine lake (the red aluminium salt).
- 46. 46 CHLOROPHYLL It is the natural green pigment abundantly found in nature. It is responsible for photosynthesis.
- 47. 47 PERFUMES ROSE It is obtained by steam distillation of the flower petals of Rosmarinus officinalis (family Labiatae). For obtaining rose oil, the blossoms (before they open) are collected a little before sunrise.
- 48. 48 JASMINE ESSENTIAL OIL: It is obtained from the flowers of Jasminum grandiflorum (family Oleaceae). For obtaining jasmine oil, solvent extraction method is used. It is used in perfumery industries.
- 49. 49 LAVENDER OIL It is obtained from the flowers and stalk of Lavandula officinalis (family Labiatae).
- 50. 50 TUBEROSE OIL It is obtained from Epimedium acuminatum (also known as mistress of the night ). Its oil is a brown, viscous liquid with a sweet, heavy and sensuous scent.
- 51. 51 GERANIUM It is obtained by distillation of the flowers, leaves and stalks of Pelargonium graveolens (family Geraniaceae).
- 52. 52 CINNAMON OIL It is obtained from the different parts of cinnamon tree, i.e., its leaves, barks, and roots of Cinnamon zeylanicum (family Lauraceae). The oil obtained from the bark is of utmost value, and has a warm, spicy and sweet character.
- 53. 53 NEROLI OIL It is an essential oil obtained by distillation of the flowers of bitter orange tree. It can be stored in amber-coloured bottles under refrigeration.
- 54. 54 BLEACHING AGENTS Mercury Compounds: Mercuric chloride (HgCl), red mercuric oxide (HgO), and ammoniated mercury are mercury compounds possessing skin bleaching properties. However, at the current time , use of mercury compounds in cosmetics is prohibited. Hydroquinones: They are used as bleaching agents at 1.5-2% concentration for temporarily lighting the skin. In 5% concentration, they may cause redness and burning of skin. Reverse action of hydroquinones occurs on exposure to sunlight. If cosmetics containing hydroquinone are discontinued, a similar effect can be observed.
- 55. 55 Catechol and its Derivatives: They exhibit skin lightning effects. 4-Isopropyl catechol is the most potent de -pigmenting agent. Catechol derivatives can cause irritation and sensitisation reaction at 3% or more concentrations. Ascorbic Acid and its Derivatives: They are not very effective as a de -pigmenting agent, but can be used safely. Ascorbic acid is mostly used in skin bleaching creams, containing hydroquinone as a stabiliser (antio xidant). Ascorbyl oleate is used at 3% and 5% concentrations in skin bleaching cream for bleaching freckles in human skin.
- 56. 56 Antioxidants Natural antioxidants (like tocopherols), present in fats and oils, are destroyed during the refining process. Hence, antioxidants should be essentially added in cosmetics to avoid the rancidity of fats and oils due to oxidative deterioration. Some commonly used antioxidants used in cosmetics are:
- 57. 57 Tamarind: Tamarindus indica (family Fabaceae) is widely grown in tropical regions. Tamarind seeds exhibit radical scavenging, anti -microbial and lipid peroxidation reducing activities. Due to its antioxidant activity, tamarind is added in anti- wrinkle cosmetics.
- 58. 58 Vitamin C: It prevents free r adical damage by donating free radicals. It boosts up the immune system. Carrots, peaches, sweet potatoes, oranges,broccoli, etc. are the major sources of vitamin C. Vitamin E: It is known as scavenger of free radicals. It is beneficial against certain types of cancer and cardiac problems. Almonds, nuts, whole cereal grains, vegetable oils, etc. are the major sources of vitamin E.
- 59. 59 Pomegranate: The extract of pomegranate plant, Punica granatum, exhibit antioxidant and antiviral properties, and enhance the effectiveness of topical sunscreens. Pomegranate seed oil exhibit chemopreventive activity against skin cancer. Pomegranate peel extracts foster dermal regeneration. Pomegranate seed oil fractions facilitate epidermal regeneration. Liquorice: Glycyrrhiza glabra extract is used to treat skin irritation, dermatitis, eczema, pruritus, and cysts. Glycyrrhizin is an important constituent of liquorice, and has a chemopreventive action.
- 60. 60 Surfactants Surfactants (or surface active agents) reduce the boundary tension in one or more than one interface in the system. They also stabilise one or more interface by forming absorbed layers. Due to these properties, surfactants are incorporated in cosmetics. Surfactants are used in the preparation of cosmetics due to the following five uses: 1) Detergency 2) Wetting 3) Foaming 4) Emulsification 5) Solubilisation
- 61. 61 Clove Oil: It is obtained from the buds of Eugenia caryophyllus (family Myrtaceae). It can also be used in perfume industries in small doses. Ambrette Oil: It is obtained by expressing the seeds of Abelmoschus moschatus (family Malvaceae). The oil is rich, sweet, floral and musky in nature. It can be used as an anti-ageing agent. Sandalwood Oil: It is obtained by steam distillation of the hard wood of Santalum album (family Sundalaceae). It is used as a fixative agent in most of the perfumes.
- 62. 62 Preservatives Preservatives are used to prevent spoilage of cosmetic products and also the growth of microorganisms. They are t he products of oxidation of oils and fats. Most cosmetic preparations, especially those containing water are prone to deterioration if not added with preservatives. An ideal preservative should possess the following characteristics: 1. It should be compatible with the formulation. 2. It should be soluble to the extent needed to achieve an effective concentratio n. 3. It should be stable enough to provide a sustained antimicrobial effect. 4. It should be colourless and odourless. 5. It should be non-irritant and non-allergic in the concentrations used. Examples- 6. Organic acids, like Benzoic acid and Formic acid. 7. Alcohols, like Ethyl alcohol and Isopropyl alcohol. 8. Aldehydes, like Formaldehyde and Cinnamic aldehyde. 9. Phenolics, like Cresol and Phenol. 10. Esters, like Methyl-p-hydroxy benzoate
- 63. 63 THANKYOU