antiseptics and disinfectants in pharmacology .pptx

A detail list of various disinfectants

1. Local anti-infective agents

2. ANTISEPTICS AND DISINFECTANTS Antiseptics: agents used on living surfaces (skin , mouth) are called antiseptics. Disinfectants: agents used for inanimate objects (instruments, equipments, water supply) are called disinfectants. Together they are k/a germicides.

3. Sterilization: means complete killing of all forms of microorganisms, including spores. Disinfection: refers to reduction in the number of viable pathogenic microbes to a level that they do not pose a risk to individuals with normal host defence.aka “sanitization” or “decontamination”

4. Classification I. Phenol derivatives: Phenol, Cresol, Chloroxylenol , Hexachlorophene. 2. Oxidizing agents: Pot. permangnate , Hydrogen peroxide, Benzoyl peroxide. 3. Halogens: Iodine, lodophores , Chlorine, Chlorophores . 4. Biguanide : Chlorhexidine .

5. 5. Quaternary ammonium (Cationic): Cetrimide , Benzalkonium chloride, Dequalinium chloride. 6. Soaps : of Sod. and Pot. 7. Alcohols: Ethanol, lsopropanol . 8. Aldehydes : Formaldehyde, Glutaraldehyde . 9. Acids: Boric acid.

6. I0. Metallic salts: Silver nitrate, Silver sulfadiazine, Zinc sulfate, Calamine, Zinc oxide. 11. Dyes: Gentian violet, Acriflavine , Proflavine . 12. Furan derivative : Nitrofurazone .

7. PHENOLS Phenol (Carbolic acid) is one of the earliest used antiseptics and still the standard for comparing other germicides. is a relatively weak agent poor action on bacterial spores acts by disrupting bacterial membranes and denaturing bacterial proteins used to disinfect urine, faeces , pus, sputum included in antipruritic preparations because of its mild local anaesthetic action. May causes skin burns and is a caustic.

8. ii) Cresol methyl-phenol more active (3- 10 times) and less damaging to tissues than phenol. Used for disinfection of utensils, excreta and for washing hands.

9. iii) Chloroxylenol : does not coagulate proteins, is noncorrosive, nonirri tating but efficacy is reduced by organic matter. poorly water soluble used for surgical antisepsis

10. iv) Hexachlorophene: chlorinated phenol is narrow spectrum: kills gram-positive but not gram-negative bacteria or spores. Use of a 3% solution for baby bath markedly reduced the incidence of staphylococcal infections, but produced brain damage (especially in premature neonates).

11. b) OXIDIZING AGENTS i )Potassium permanganate: occurs as purple crystals highly water soluble liberates oxygen which oxidizes bacterial protoplasm. Pot. permanganate has also been used to disinfect water and for stomach wash in alkaloidal poisoning

12. ii)Hydrogen peroxide: liberates nacent oxygen which oxidizes necrotic matter and bacteria. Hydrogen peroxide has poor penetrability and a weak, transient action. It loses potency on storage. iii) Benzoyl peroxide: It is specifically active against Propionibacterium acnes and used on acne vulgaris .

13. c)HALOGENS Iodine: rapidly acting, broad-spectrum (bacteria, fungi, viruses) microbicidal agent Acts by iodinating and oxidizing microbial protoplasm. Tincture iodine (2% in alcohol): used on cuts, for degerming skin before surgery Iodine crystals are corrosive. stronger solutions (> 5%) cause burning and blistering of skin.

14. ii) lodophores : are soluble complexes of iodine with large molecular organic compounds that serve as carriers- release free iodine slowly. Povidone ( Polyvinylpyrrolidone ) iodine: nonirritating, nontoxic, nonstaining and exerts prolonged germicidal action. Treated areas can be bandaged or occluded without risk of blistering. used on ulcers, burns, otitis externa and other superficial wounds, as well as for surgical scrubbing, disinfection of instruments

15. iii) Chlorine: highly reactive element and a rapidly acting potent germicide. 0. 1--0.25 ppm kills most pathogens (but not M. tuberculosis) in 30 sec. is used to disinfect urban water supplies. organic matter binds chlorine, so that excess has to be added to obtain free chlorine concentration of 0.2-0.4 ppm . This is known as the 'chlorine demand' of water.

16. iv) Chlorophores compounds that slowly release hypochlorous acid ( HOCI). because of ease of handling, they are used in preference to gaseous chlorine. Chlorinated lime (bleaching powder): is obtained by the action of chlorine on lime ( CaO ); resulting in a mixture of calcium chloride and calcium hypochlorite. On exposure. it decomposes releasing 30- 35% w/w chlorine. used as disinfectant for drinking water, Swimming pools etc.

17. Sodium hypochlorite solution: Contains 4- 6% sodium hypochlorite that is a powerful disinfectant is unstable and too irritant to be used as antiseptic, except for root canal therapy in dentistry.

18. d) BIGUANIDE i ) Chlorhexidine : A powerful , non irritating, cationic antiseptic disrupts bacterial cell membrane and denaturation of microbial proteins is relatively more active against gram-positive bacteria extensively used for surgical scrub, neonatal bath, mouthwash, obstetrics and as general skin antiseptic. 0.2% in gingivitis

19. e) QUATERNARY AMMONIUM (CATIONIC) ANTISEPTICS are detergents; cidal to bacteria, fungi and viruses. However, many gram-negative bacteria (especially Pseudomonas), M. tuberculosis and bacterial spores are relatively resistant. Cationic antiseptics act by altering permeability of cell membranes and denaturing of bacterial proteins.

20. Soaps, being anionic, neutralize their action, while alcohol potentiates they are widely used as sanitizers, antiseptic and disinfectant for surgical instruments, gloves etc, but should not be considered sterilizing.

21. Cetrimide is a soapy powder with a faint fishy odour good cleansing action. Alone or in combination with chlorhexidine , it is one of the most popular hospital antiseptic and disinfectant for surgical instruments, utensils, baths, etc

22. ii) Benzalkonium chloride ( Zephiran ) It is highly soluble in water and alcohol. A I: IOOO solution is used for sterile storage of instruments and I in 5000 to I in I0,000 as antiseptic for irrigation, etc. iii) Dequalinium chloride Has been used in gum paints and lozenges.

23.   f) SOAPS Soaps are anionic detergents with weak antiseptic action. They affect only gram-positive bacteria. Their usefulness primarily resides in their cleansing action.

24. g) ALCOHOLS Ethanol: is an effective antiseptic and cleansing agent at 40- 90% concentration acts by precipitating bacterial proteins. A cotton swab soaked in 70% ethanol rubbed on the skin kills 90% bacteria in 2 min. Low concentrations enhance the antiseptic activity of iodine and chlorhexidine when used as solvent for these. ii) lsopropanol : is less volatile; can be used in place of ethanol.

25. h) ALDEHYDES: Formaldehyde: is a pungent gas denatures proteins and is a general protoplasmic poison, but acts slowly. A 37% aqueous solution called Formalin Used for hardening and preserving dead tissues. employed to disinfect instruments and excreta

26. ii) Glutaraldehyde is less volatile, less pungent, less irritating and better sterilizing agent than formalin, but needs to be activated by alkalinization of the solution. exerts broad-spectrum activity against bacteria, fungi and viruses A 2% solution is used to disinfect surgical instruments and endoscopes, but prolonged contact is needed.

27. i ) ACIDS 1)Boric acid bacteriostatic and a very weak antiseptic nonirritating even to delicate structures, saturated aqueous soluuons (4%) have been used for irrigating eyes and as mouthwash, douche, etc Boroglycerine paint (30%) is used for stomatitis and glossitis . systemic absorption causes vomiting. abdominal pain, diarrhoea , visual disturbances and kidney damage.

28. j) METALLIC SALTS i )Silver compounds: These are astringent and caustic. They react with SH, COOH, PO, and NH, groups of proteins. Silver nitrate: rapidly kills microbes action persisting for long periods because of slow release of Ag ions from silver proteinate formed by interaction with tissue proteins.

29. tissues get stained black due to deposition of reduced silver. highly active against gonococci and 1% solution is used for ophthalmia neonatorum . Silver sulfadiazine It is highly active against Pseudomonas and has been used on burns.

30. ii) Zinc salts are astringent and mild antiseptics Zinc sulfate: highly water soluble 0.1 - 1% is used for eyewash and in eye/ear drops Applied to skin, it decreases perspiration. White lotion containing 4% each of zinc sulfate and sulfurated potash has been used for acne and impetigo.

31. Calamine and zinc oxide: These are insoluble. In addition to being mildly antiseptic, they are popular dermal protectives

32. k) DYES i ) Gentian violet (crystal violet): A rosaniline dye active against staphylococci, other gram-positive bacteria and fungi, but gram-negative organisms and mycobacteria arc insensitive Stains the surface Aqueous or alcoholic solution (0.5-1%) has been used on bedsores, chronic ulcers etc.

33. ii) Acriflavine and Proflavine : are orange-yellow acridine dyes active against gram-positive bacteria and gonococci. are nonirritant, do not retard healing, and are particularly suitable for chronic ulcers and wounds. Bandage impregnated with acriflavine-vaseline is used for burn dressing

34. Triple dye lotion = gentian violet 0.25% + brilliant green 0.25% + acriflavine 0.1% used for burns and for dressing umbilical stump in neonates.

35. l) FURAN DERIVATIVES Nitrofurazone ( Nitrofural ): cidal to both grampositive and negative, aerobic and anaerobic bacteria, even in high dilutions, but activity is reduced in the presence of serum. acts by inhibiting enzymes necessary for carbohydrate metabolism in bacteria. is highly efficacious in burns and for skin grafting.

36. other furan derivatives: Nitrofurantoin  for UTI Furazolidone  for intestinal infections

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