Protective/ Topical agentsBy Dr. Taj Khan Dept. of Pharmaceutical Chemistry, Oriental college of pharmacy Sanpada, New Mumbai.

Definition: Topical means pertaining to a particular locality or place or simply it means “local”. Substances which are applied directly on the skin or mucous membrane or any other surface.

Protective and adsorbents: drugs which adsorb intestinal toxins, bacteria etc, and give a protective coating to the inflamed mucus memb.

3MgO, 4SiO2, H2O Test for Purity Acidity or alkalinity Water-Soluble substances Acid-Soluble substances Iron Carbonates Loss on drying Organic compounds Chloride

Talc talcum, french chalk, purified talc

Storage: Talc is an inert substance not affected by acids or bases

or other chemicals. So store in a well closed container. Medicinal and pharmaceutical Uses: Pharmaceutical aid (dusting powder). Used as a

filtering and distributing medium in the preparation of aromatic waters etc.

Main ingredient in talcum powders and dusting powders

Talc

Preparation Zinc oxide is prepared on a large scale by burning

zinc metal in a current of air. 2Zn + O2 = 2ZnO

Insoluble Zn compounds:Zinc oxide/ZnO

Assay: The sample is dissolved in 2M acetic acid and diluted with water.

Xylenol orange titrurate and sufficient hexamine to produce violet pink colour are added. A further quantity of hexamine is added and titrated with 0.1M disodium edetate until the solution becomes yellow.

In this complexometric titration hexamine is added to raise the pH to the alkaline side and the zinc oxide converted to zinc acetate by dissolving in acetic acid and titrated with 0.1M disodium edetate using xylenol orange as indicator. Zinc is complexed by the disodium edetate and the indicator changes colour from violet-pink to yellow at the end point.

ZnO

Test for Purity Alkalinity Carbonates and substances insoluble in acids. As Fe Pb Loss or ignition Storage: Since it absorbs CO2 from the air, store it in a well closed

container. Medicinal Use: Astrigent and topical protective. ZnO is a mild antiseptic and

astringent. In the form of ZnO ointment or dusting powder, it is used in the treatment of eczema, ringworm, pruritus and psoriasis. It is also widely used in the mfg of plasters.

ZnO

Zinc Oxide Paste Zinc Oxide: 250 gm Starch: 250 gm White Soft Paraffin: 500 gm

Zinc Oxide Ointment Zinc Gelatin

ZnO

Mixture of Zn salts obtained from commercial stearic acid which itself is prepared from the hydrolysis of fats. It consists mainly of variable proportions of Zinc stearate and Zinc palmitate. Test for Purity Acidity or alkalinity Alkalis and alkaline earths Chloride Arsenic Heavy metals Sulphate Storage: Store in well closed containers. Medicinal and Pharmaceutical Uses: Dusting powder. Since zinc stearate is a mild antiseptic and astringent, it is used in the form of dusting powder or ointment in several skin conditions. Sometimes it is used as solid diluents.

Zinc stearate/(C17H35COO)2Zn

Calamine BP: Basic ZnCO3 suitably colored with ferric oxide. Calamine IP: ZnO colored with Ferric oxide. It is an amorphous, reddish brown powder and the color depends on the variety and amount of ferric oxide present and the method by which it is incorporated. It is practically insoluble in water and completely soluble in mineral acids. Since there is a possibility of adulteration with dyes, there are tests for water soluble dyes and alcohol soluble dyes.

Calamine

Test for Purity Acid-insoluble substances Alkaline substances Arsenic Calcium Lead Water-soluble dyes Alcohol-soluble dyes Loss on ignition

Storage: Store in well closed containers. Medicinal and Pharmaceutical Uses: Topical protective. Widely used in lotions, ointments and dusting powders as soothing agent. It is used in sunburns, eczema and urticaria and some other skin conditions. Calamine lotion (Lotio Calaminae) is very popular.

Calamine

Calamine LotionCalamine: 150 gmZinc Oxide: 50 gmBentonite: 30 gmSodium Citrate: 5 gmLiquefied Phenol: 5 mlGlycerin: 50 mlRose Water: qs 1000 ml

Other calamine preparationsCalamine CreamCalamine Ointment

Calamine

Occurs in nature in the mineral rutile, brookite and ilmenite. Magnetic iron ores usually contain titanium.

Preparation: prepared by heating ilmenite FeTiO3 with hydrogen chloride and chlorine.

2FeTiO3 + 4HCl + Cl2 = 2FeCl3 + 2TiO2 +2H2O Test for Purity Clarity and color of solution Acidity or alkalinity Water-soluble substances Arsenic Barium Heavy metals Iron

Titanium Dioxide TiO2

Storage: Well closed containers made of glass or any metal

other than Al.

Medicinal and Pharmaceutical Uses: Pharmaceutical Aid and Topical Protective. Since it spreads well, it is used as a white pigment in paints. Because of its high RI it is used in sun-tan preparations.

Titanium Dioxide TiO2

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These are the chemicals & their preparations used in reducing or preventing infection due to microorganisms.Antiseptic: Inhibit the growth of MO (used for living object)Disinfectant: Destroy the Pathogenic MO (used for non living object)Germicides: Kill Bacteria, Fungi, Viruses, SporesBacteriostatic: Primarily inhibit the Bacteria – Only arrest their growth not kill them.Sanitizers: For maintaining the health for sanitization purpose

Antimicrobial Agents and Astringents

Uses of antimicrobial agents:1% solution used for using into the eyes of newborn babies, as prophylactic measure against opthalmia neonaturum.Effective against gonoccocal organisms.0.5% aqs soln in the form of wet dressing applied to third degree burn.

Mechanism Of Action1: Oxidation2: Halogenation3: Protein Precipitation

Antimicrobial Agents and Astringents

CLASSIFICATION OF DISINFECTANTS AND ANTISEPTICS

1. Halogens (chlorinated lime, chloramine B, chlorhexidine, iodovidone)

2. Oxidizing agents (hydrogen peroxide, potassium permanganate)

3. Acids (boric acid)

4. Phenol derivatives (phenol, cresol,)

5. Aldehydes and alcohols (formaldehyde, ethanol, isopropanol)

6. Metallic salts (silver nitrate, zinc sulfate, and copper sulfate)

7. Dyes or tints (brilliant green, methylene blue)

8. Detergents (decamethoxinum, soaps)

Antimicrobial Agents and Astringents

Hydrogen peroxide, H2O2

Laboratory method: BaO2.8H2O + H2SO4 → BaSO4 ↓+ H2O2 + 8H2O

Industrial method: 2H2SO4 → H2S2O8 (aq.) + H2

H2S2O8 + 2H2O → 2H2SO4 + H2O2

Oxidative anti-microbial agents:

By redox process: Industrially H2O2 is prepared by the auto-oxidation of 2-alkylanthraquinols. The process involves a cycle of reactions.

The H2O2 formed (about 1%) is extracted with water and concentrated.

Hydrogen peroxide, H2O2 Test for purity: Acidity Organic stabilizers Non-volatile matter Storage: H2O2 is not stored in glass bottles since the alkali metal oxides present in glass catalyzes its decomposition. It is, therefore, stored in paraffin wax coated glass, plastic or teflon bottles. Small amounts of acid, glycerol, alcohol, acetanilide and H3PO4 are often used as stabilizers to prevent its decomposition.

Uses of H2O2 :(i) Antiseptic and germicide for washing wounds, teeth and ears, under the name of perhydrol. (ii) In the mfg of sodium perborate, sodium percarbonate. These are used in high quality detergents. (iii) As an antichlor. (iv) In the detection of Ti, V and Cr ions with which it forms peroxides of characteristics colours. (v) In the production of epoxides, propylene oxide and polyurethanes. (vi) In the synthesis of hydroquinone, (cephalosoporin) and food products like tartaric acid.

Zinc peroxide, ZnO2

It is odourless white or yellowish solid.It is produced by adding ZnO or zinc hydroxide to a solution of H2O2. It can also be synthesized through the reaction of zinc chloride and hydrogen peroxide.It is stable, insoluble in water and dissolves in acid forming H2O2 . It decomposes at 150 OC to release O2

Storage: Oxidiser, store in cool, away from lightAway from incompatible materials (organic and reducing subs)Use: Anti-microbial agent in topical preparation, additive for aseptic productsIt was historically used as a surgical antiseptic.

It enhance patient’s oral hygiene. Safety, low cost, low abrasivity, water solubility, buffering ability, compatibility with fluoride, and in high concentrations, antimicrobial properties.Incorporated into mouthrinses and dentrifices It raise salivary pH that is lower than 8 (i.e. increase saliva alkalinity). Additionally, sodium bicarbonate due to its slightly abrasive consistency works as a mechanical cleanser of teeth and gingival tissues.

Sodium bicarbonate NaHCO3, baking soda

Salt consisting of K+ and MnO4− ions. Formerly known as permanganate of potash or Condy's crystals, it is a strong oxidizing agent.

Test for Purity: Cl and SO4 Water-insoluble matter Color of the solution Storage: should be kept separated from oxidizable substances. Store in

well- closed containers. Uses: As an oxidant, antiseptic Permanganate washes were once used to treat gonorrhea and are

still used to treat candidiasis. Antidote for strychnine

Potassium permanganate, KmnO4

Root canal irrigating solution is due mainly to its efficacy for pulpal dissolution and antimicrobial activity. 1% sodium hypochlorite, acceptable biological compatibility.It is the most used irrigating solution in endodontics, because its mechanism of action causes biosynthetic alterations in cellular metabolism and phospholipid destruction, formation of chloramines that interfere in cellular metabolism, oxidative action with irreversible enzymatic inactivation in bacteria, and lipid and fatty acid degradation.

Sodium hypochlorite NaOCl

A dark violet (Greek, ioeides, violet) non-metallic halogen element belonging to Group VIIb of the periodic table.

Preparation: Prepared by heating KI or NaI with dil. H2SO4 and manganese dioxide. 2KI + MnO2 + 3H2SO4 → I2 + 2KHSO4 + MnSO4 + 2H2O

Iodine, I2

Test for Purity: Bromides and chlorides Non-volatile matter Storage: It is volatile in nature. Iodine topical solution should be

stored in light-resistant containers at a temperature not exceeding 35 °C and iodine tincture should be stored in air-tight containers. Uses: solution in alcohol, called "tincture of iodine" is used as antiseptic In the manufacture of dyestuffs and drugs, and as a reagent in analytical chemistry.

Iodine, I2

Povidone-iodine (PVP-I) is a stable chemical complex of polyvinylpyrrolidone (povidone, PVP) and elemental iodine. It contains from 9.0% to 12.0% available iodine, calculated on a dry basis.

Test for Purity: Heavy metals Nitrogen iodide sulphated ash LOD

Storage: Since it slightly hygroscopic in nature, store in a well closed , light resistant containers. Uses: It is used as a disinfectant. Broad spectrum antiseptic for topical application in the treatment and prevention of infection in wounds.

Povidone-I2

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Are protein precipitant with Ltd penetration powerIt coagulates the protein on the surface of the cell and brings out hardening effect.It constricts the tissue: Small Blood vesselsThese are mild Antimicrobial AgentsUSES:Styptic to arrest minor bleeding by coagulation of bloodAnti-perspirant to reduce perspiration by constricting pores of skinAnti-inflammatory actionAt high concentration to remove unwanted tissue growthInternally they can used in diarrheaAs cosmetic as skin tone and bring out the hardening effectIn dental products it can promotes hardening of the gumsIt reduces the cell permeability

Astringents

Aluminum Compound Alum: Potash Alum:[KAl(SO4)2, 12H2O] Ammonia Alum:[NH4Al(SO4)2,12H2O] Formula: AlK(SO4)2, 12H2O Synonyms: Aluminium Potassium Sulphate, Potash Alum, Potassium Alum Uses: Large dose gives irritation and gives Gum Necrosis, GI

Haemorrhage, adjuvant with vaccine (DTP) Alum precipitate proteins To apply on sores Used as mordant in dyeing industry. (a substance, that

combines with a dye or stain and thereby fixes it in a material.)

Astringents

Three forms are official - heptahydrate, hexahydrate, monohydrateFormula: ZnSO4.7H2OPreparation:Zns + 2O2 → ZnSO4

Zn + H2SO4 → ZnSO4 + H2Properties:Colorless, transparent crystals, odorlessVery soluble in water; practically insoluble in ethanolUses:In variety of Skin condition (keratosis), viral infection of genitals, pityriasis (skin rash).Water soluble Zn is used as supplements for Zn deficiency.SE: When taken internally: Causes abdominal pain, dyspepsia, nausea, vomiting, diarrhoea, gastric irritationIn high dose - anemia, neutropenia

Zinc Sulfate ZnSO4

Inorganic compound with chemical formula AgNO3. Test for Purity: clarity and color of the solution acidity and alkalinity foreign salts Al, Bi, Cu and Pb Storage: Affected by light, store in tightly closed light resistant

containers. Uses: Antiseptic properties. Until the development of antibiotics, dilute solutions of AgNO3 used to be dropped into newborn babies' eyes at birth to prevent contraction of gonorrhea from the mother.

Silver Nitrate, AgNO3

Protein precipitant antimicrobial agents

Boric acid, H3BO3, B(OH)3

aka hydrogen borate, boracic acid, orthoboric acid & acidum boricum. Colorless crystals or a white powder that dissolves in water.

Antimicrobial Agents and Astringents

Preparation of boric acid: Reacting borax (sodium tetraborate decahydrate) with a mineral acid: Na2B4O7·10H2O + 2HCl → 4 B(OH)3 [or H3BO3] + 2NaCl + 5H2O It is also formed as a by product of hydrolysis of boron trihalides and diborane: B2H6 + 6H2O → 2B(OH)3 + 6H2 BX3 + 3H2O → B(OH)3 + 3HX (X=Cl, Br, I)

Antimicrobial Agents and AstringentsBoric acid

Assay: Assayed by acid-base titration. Sample + water + glycerol titrate against standard sodium hydroxide using phenolphthalein.

Test for Purity: clarity and color of the solution SO4

solubility in ethanol As Heavy metals LOD Storage: stable in air. store in well closed containers. Uses:

Antiseptic for minor burns or cuts and is sometimes used in dressings. Very dilute solution as an eye wash. Dilute boric acid can be used as a vaginal douche to treat bacterial vaginosis due to excessive alkalinity. For acne treatment. For prevention of athlete's foot, by inserting powder in the socks or stockings.

Antimicrobial Agents and AstringentsBoric acid