Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
5/9/2017 Preservatives, Antiseptics and Disinfectants 1 PHL424 PRESERVATIVES, ANTISEPTICS, DISINFECTANTS Dr. Sarah I Bukhari Associate Professor of Microbiology College of Pharmacy King Saud University 5/9/2017 Preservatives, Antiseptics and Disinfectants 2 PRESERVATIVE • Deterioration of pharmaceutical products may result from: • Chemical or physical changes • Microbial contamination • Microbial contamination is prevented or minimized by mainly by adding preservative • Preservatives added to pharmaceutical or food products to; • Prevent microbial spoilage • keep levels of microorganisms to a low and safe level 5/9/2017 Preservatives, Antiseptics and Disinfectants 3 Characters of Ideal Preservative 1. Effective in low concentration 2. Broad spectrum 3. Non-toxic, non-irritant, non-corrosive and no 4. 5. 6. 7. 8. offensive odor Must have adequate stability Active at room temperature Compatible with the preparations and its activity not affected by the ingredients. Active in presence of large number of microorganisms and spore Resist the attack by the microorganisms. 5/9/2017 Preservatives, Antiseptics and Disinfectants 4 Which pharmaceutical products need preservative? A. Sterile products • The function of preservative is to maintain sterility Parenteral injections when dispensed in multi-dose 2. Ophthalmic products 1. B. Non-sterile products • The function of preservative is to destroy or to prevent the growth of microbes • In oral and topical use • Sometimes preservatives combination is required 5/9/2017 Preservatives, Antiseptics and Disinfectants 5 Commonly used preservatives 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. Esters of parahydroxy benzoic acid (Parabens) Benzoic acid and sodium benzoate( 0.1-0.2%) Sorbic acid Benzalkonium chloride (0.002-0.01%), Cetermide Chlorhexideacetate(0.02~0.05%) Alcohol (15-20%) Chlorobutanol Phenol (0.1-0.5%) Cresol (0.1-0.5%) Phenylmercuric nitrate and acetate ( 0.002-0.01%) Thiomersal 5/9/2017 Preservatives, Antiseptics and Disinfectants 6 Parabens • Esters of parahydroxy benzoic acid • Methyl, ethyl, propyl & butyl esters & their sodium salts • The most widely used group of preservatives • Most effective at a pH 7~9. • Concentrations of 0.1~0.2% are normally used • Suitable for both external and internal use. • Usually used in combination, such as ethyl:propylester (1:1) or ethyl:butylester(4:1). 5/9/2017 Preservatives, Antiseptics and Disinfectants 7 Benzoic acid and sodium benzoate Good antifungal and antibacterial preservative used at a pH of less than 4. Concentration of 0.03~0.1% is recommended. Sodium benzoate: 0.1~0.25%. Only the undissociated fraction or molecular form of a preservative possesses preservative capacity because the ionized portion is incapable of penetrating M.O. 5/9/2017 Preservatives, Antiseptics and Disinfectants 8 Sorbic acid and its salts (sorbates) • Sorbic acid has similar properties to benzoic acid. • Also only effective in acidic conditions (pH 4.5). • Concentrations of 0.05~0.3% are used. • Suitable for oral use. • In general the salts are preferred over the acid form because they are more soluble in water, but it is the acid form that is active 5/9/2017 Preservatives, Antiseptics and Disinfectants 9 Preservatives used in injections • Phenol • Cresol • Chlorocresol • Benzyl alcohol 0.5 0.3 0.1 0.9 5/9/2017 Preservatives, Antiseptics and Disinfectants 10 Preservatives used in eye drops • Chlorobutol • Chlorhexidine • Phenylmercuric nitrate • Benzalkonium chloride • Phenyl ethyl alcohol 0.5 0.01 0.002 0.01 0.5 5/9/2017 Preservatives, Antiseptics and Disinfectants 11 Preservatives used in oral • Ethyl alcohol 15 • Chloroform 0.2 • Benzoic acid 0.1 • Sodium benzoate 0. 1 • Methyl and propyl hydroxy benzoate 0.1-0.2 5/9/2017 Preservatives, Antiseptics and Disinfectants 12 5/9/2017 Preservatives, Antiseptics and Disinfectants 13 DISINFECTANTS • Disinfection: Reducing number of pathogenic organisms to point where they no longer cause diseases • May use physical or chemical methods. • Disinfectant: Chemical or Physical agent applied to inanimate objects to destroy microbes that causing disease but not necessary resistant spore forming • Disinfectants are used on inanimate objects 5/9/2017 Preservatives, Antiseptics and Disinfectants 14 IDEAL DISINFECTANT • Effective at room temperature • Not activated by organic matter • Compatible with soaps and detergents • Noncorrosive, nonirritant, non-staining nontoxic • Inexpensive • Capable of killing all pathogenic organisms • Require limited time of exposure 5/9/2017 Preservatives, Antiseptics and Disinfectants 15 ANTISEPTIC • Agent applied to living tissue animate (skin and mucous membranes) to inhibit or kill microbes • Must be capable of preventing sepsis • Non-toxic, non-irritating, non-statining • Usually less efficient than disinfectants • Examples: 70% ethanol, Povidone Iodine 5/9/2017 Preservatives, Antiseptics and Disinfectants 16 CHEMICAL CLASSES OF DISINFECTANTS/ANTISEPTICS 1. Phenol and phenolics 2. Surface active agents 3. Biguanides 4. Heavy metals 5. Alcohols 6. Halogens 7. Aldehydes 8. Oxidizing agents 5/9/2017 Preservatives, Antiseptics and Disinfectants 17 CLASSIFICATION ACCORDING TO THE ACTIVITY 1. High level disinfectant • Called chemical sterilants • Destroy vegetative bacteria, mycobacteria, fungi and enveloped (lipid) and nonenveloped (non lipid) viruses • Not necessarily bacterial spores 2. Intermediate level disinfectiant • Kill vegetative bacteria, mycobacteria, most fungi, most viruses • Have little or no sporicidal activity 2. Low level disinfectants • Kill most vegetative bacteria, enveloped viruses, some fungi • Do not kill mycobacteria or bacterial spores • Typically used to clean environmental surfaces 5/9/2017 Preservatives, Antiseptics and Disinfectants 18 CLASSIFICATION OF ITEMS 1. Non Critical items: • Those that either come in contact with only intact skin but not mucous membranes or do not directly contact the patient • Involves cleaning and/or low level disinfection 2. Semi Critical items: • Devices that come in contact with non-intact skin or mucous membranes but ordinarily do not penetrate them • Involves careful cleaning followed preferably by high-Level-disinfection 3. Critical items: • Instruments & devices that enter sterile tissues • High risk of infection if the item is contaminated • Involves particular cleaning followed by sterilization Disinfectants 5/9/2017 Preservatives, Antiseptics and Disinfectants 19 Low-level Phenols, Biguanides, Quats Intermediatelevel Alcohols, Halogens High-level Aldehydes, H2O2, Paracetic acid -QUAT=quaternary ammonium compounds 5/9/2017 Preservatives, Antiseptics and Disinfectants 20 Microbicial activity Bacteria G+ G- TB Viruses Spore Lipophilic Hydrophilic Phenols HS HS R R S R Quats HS HS R R S R Biguanides HS MS R R V R Alcohols HS HS S R S V Iodine/Hypochlorite HS HS S S S R/S Aldehydes S S S MS HS HS 5/9/2017 Preservatives, Antiseptics and Disinfectants 21 TYPES OF DISINFECTANTS/ANTISEPTICS Low-Level Disinfectants 1. Phenolics 2. quaternary ammonium compounds 3. Cationic Biguanides 4. Mercurials 5/9/2017 Preservatives, Antiseptics and Disinfectants 22 Types of Disinfectants/Antiseptics 1. Phenol, Phenolics and bisphenols • Low to Intermediate-level disinfectants • Denature proteins & disrupt cell membranes A. Phenol: oldest surgical antiseptic (Not used) • Now, neither used as disinfectant or antiseptic • Corrosive effect on tissues & carcinogenic • Disagreeable odor and possible side effects • Now, just used for evaluating disinfectants 5/9/2017 Preservatives, Antiseptics and Disinfectants 23 Types of Disinfectants/Antiseptics B. • • • • Phenolics: derivatives of phenol to diminish side effects Detergents are added to clean & remove organic material and to increase antimicrobial activity Stable and persist for long periods Used to disinfect hard surfaces in hospitals and lab Good for disinfecting things like pus, saliva, and feces • Cresols are phenolics that are derived from coal tar • Cresol(O-phenylphenol): main ingredient in Lysol 5/9/2017 Preservatives, Antiseptics and Disinfectants 24 Types of Disinfectants/Antiseptics C. Bisphenols: have 2 phenolic groups Hexachlorophene • Particularly good against gram-positive strep & staph • Can cause neurological damage ii. Triclosan • Used in soaps, toothpaste • Broad spectrum, especially against G+ & fungi i. 5/9/2017 Preservatives, Antiseptics and Disinfectants Phenol and phenolics 25 5/9/2017 Preservatives, Antiseptics and Disinfectants 26 Types of Disinfectants/Antiseptics 2. SURFace ACTive AgeNT (SURFACTANTS) • Reduce surface tension • Types of surfactants: anionic, cationic, nonionic, amphoteric a. Anionic (Soaps and detergents) • Soaps have hydrophilic and hydrophobic ends •Good degerming agents but not antimicrobial • Detergents are positively charged organic surfactants 5/9/2017 Preservatives, Antiseptics and Disinfectants 27 Quaternary ammonium compounds Benzathonium 5/9/2017 Preservatives, Antiseptics and Disinfectants 28 Types of Disinfectants/Antiseptics b. Cationic surfactants: quaternary ammonium compounds (Quats) • Derivatives of ammonium chloride • Substitutions → compounds with variable degree of antimicrobial activity • Benzalkonium chloride, benzathonium cetylpyridinium chloride, Cetrimonium bromide • chloride, Inactivation of energy-producing enzymes, denaturation of proteins & disruption of cell membrane • Used in sanitation of non-critical surfaces • Instruments that contact skin (Blood pressure cuffs) • Used in mouth rinses and sore throat remedies. 5/9/2017 Preservatives, Antiseptics and Disinfectants 29 Types of Disinfectants/Antiseptics 3. Cationic Biguanides • Chlorhexidine: most popular antiseptic of this group • Disrupts the cytoplasmic membrane • Relatively ineffective against other G-ve, fungi, most viruses • Antiseptic solution, mouth wash, skin cream • Savlon is combination of chlorhexidine & cetermide • Chlorhexidine is deactivated by forming insoluble salts with anionic compounds 5/9/2017 Preservatives, Antiseptics and Disinfectants Chlorhexidine 30 5/9/2017 Preservatives, Antiseptics and Disinfectants 31 Types of Disinfectants/Antiseptics 4. Heavy Metals • Heavy-metal ions denature proteins • Combine with sulfhydryl (—SH) groups • Silver, mercury, copper, and zinc are used as germicidals • Low-level bacteriostatic and fungistatic agents • Copper controls algal growth 5/9/2017 Preservatives, Antiseptics and Disinfectants 32 Silver • 1% silver nitrate to prevent ophthalmia neonatorum • Silver impregnated wound dressings are protective against antibiotic-resistant bacteria • Silver sulfadiazine - topical cream for burns • Surfacine - water-insoluble silver iodide in a polymer carrier, persistent for at least 13 days, can be used on animate and inanimate objects • Silver nanoparticle infused commericial products plastic food storage containers keep food fresher, minimizes odors in athletic clothing. 5/9/2017 Preservatives, Antiseptics and Disinfectants 33 Mercury • Primarily bacteriostatic but broad range of activity i. Mercuric chloride was used to treat syphilis ii. Other mercurials: Mercurochrome and Merthiolate Mercurochrome (merbromin®) compound containing mercury & bromine Topical antiseptic used for minor cuts and scrapes Its use has been old-fashioned Replaced by other agents (Betadine®) Still used in developing countries (Low price) Merthiolate (thimerosal®) compound containing mercury & sodium Thimerosal used to preserve vaccines Tincture Topical antiseptic solution (NOT USED NOW) 5/9/2017 Preservatives, Antiseptics and Disinfectants 34 Mercurochrome (merbrominR) 5/9/2017 Preservatives, Antiseptics and Disinfectants 35 Merthiolate (thimerosal®) 5/9/2017 Preservatives, Antiseptics and Disinfectants 36 Copper and Zinc • Copper • Copper sulfate is used to control green algae growth in ponds, pools, reservoirs and fish tanks • Copper compounds are sometimes used in paint to prevent mildew • Zinc • Zinc chloride is used in some mouthwashes • Zinc pyrithione is fungistatic and bacteriostatic • 1-2% used in antidandruff shampoos 5/9/2017 Preservatives, Antiseptics and Disinfectants 37 5/9/2017 Preservatives, Antiseptics and Disinfectants 38 TYPES OF DISINFECTANTS/ANTISEPTICS Intermediate-Level Disinfectants 5. Alcohols 6. Halogen 5/9/2017 Preservatives, Antiseptics and Disinfectants 39 Types of Disinfectants/Antiseptics 5. Alcohols • Intermediate-level disinfectants/antiseptic • Bactericidal (G + & G-), Tuberculocidal, Virucidal (Lipophilic & some hydrophilic viruses), Fungicidal • Non-sporicidal • Denature proteins & disrupt cytoplasmic membrane • Aqueous ethanol (60-95%) & isopropanol (62-65%) • 70% is the best concentration • Absolute alcohols are not active WHY? • Because denaturation requires water • Alcohol evaporate quickly & leave no residue behind 5/9/2017 Preservatives, Antiseptics and Disinfectants 40 Types of Disinfectants/Antiseptics 5. Alcohols • Isopropanol is slightly active than ethanol for E.coli and S. aureus • More effective than soap • Not good for wound disinfection because proteins coagulate and form a protective coat around bacteria • In tinctures, they enhance the effectiveness of other antimicrobial chemicals 5/9/2017 Preservatives, Antiseptics and Disinfectants 41 5/9/2017 Preservatives, Antiseptics and Disinfectants 42 Types of Disinfectants/Antiseptics 6. Halogens and halogens containing compounds • Some halogens (iodine and chlorine) are used alone or as components of inorganic or organic solutions • Intermediate-level disinfectant/antiseptic • Denatures proteins by breaking disulfide bonds • Combine with certain amino acids to inactivate enzymes and other cellular proteins 5/9/2017 Preservatives, Antiseptics and Disinfectants 43 Types of Disinfectants/Antiseptics 6. Halogens and halogens containing compounds • Iodine kills rapidly than chlorine • Iodine formulations i. Iodine tincture (2% I2 & 2.5% KI in alcohol) ii. Iodophors (povidone/ polyvinylpyrrolidone -iodines, Betadine®) are preparation containing free iodine & povidone (inert carrier) that maintain iodine conc by complexing with free iodine • Povidone is surface active – improves wetting actions • Iodophors are less irritating and less likely to produce hypersensitivity than iodine tincture 5/9/2017 Preservatives, Antiseptics and Disinfectants 44 Types of Disinfectants/Antiseptics • Chlorine • The germicidal action is based on the formation of • • • • hypochlorous acid when chlorine is added to water Good oxidizing agent Chlorine is used as a disinfectant in gaseous form (Cl2 ) or in the form of a compound, such as calcium hypochlorite (Semmelweis's lime water), sodium hypochlorite (NaOCl, Clorox), sodium dichloroisocyanurate, and chloramines. Used to disinfect drinking water and swimming pools 2 drops Clorox/L (4 if cloudy) and let sit 30 minutes 5/9/2017 Preservatives, Antiseptics and Disinfectants 45 5/9/2017 Preservatives, Antiseptics and Disinfectants 46 TYPES OF DISINFECTANTS/ANTISEPTICS High-Level Disinfectants 7. 8. Aldehydes Oxidizing agents 5/9/2017 Preservatives, Antiseptics and Disinfectants 47 Types of Disinfectants/Antiseptics 7. ALDEHYDES • Compounds containing terminal –CHO groups • Alkylating • • • • agents- denature proteins and inactivate nucleic acids Chemical disinfectants and sterilant High level disinfection Glutaraldehyde, formaldehyde See under chemical sterilization 5/9/2017 Preservatives, Antiseptics and Disinfectants Glutaraldhyde • 2% aqueous solution • Bactericidal • Resist spores between 10-30 min – Sporicidal within 10 h • Used to sterilize and disinfect medical instruments such as endoscopes, respiratory therapy, for kidney dialysis machines, endoscopes 48 5/9/2017 Preservatives, Antiseptics and Disinfectants Ortho-phthalaldehyde (OPA) • OPA is a chemical sterilant • Similar to gluteraldehyde in antimicrobial activity • OPA has advantages compared to gluteraldehyde • Has stability over a wide pH range (pH 3-9) • Not irritant to the eyes and nasal passages • Does not require exposure monitoring • Requires no activation • Has excellent material compatibility like gluteraldehyde • Potential disadvantage of OPA • It stains proteins (Skin) gray 49 5/9/2017 Preservatives, Antiseptics and Disinfectants 50 Formaldhyde • High level disinfection (1-10%) • Limited use • Used in unusual conditions requiring decontaimination of large rooms • Used to sterilize and disinfect medical instruments such as endoscopes • Bactericidal • Resist spores between 10-30 min – Sporicidal 10 h 5/9/2017 Preservatives, Antiseptics and Disinfectants 51 Types of Disinfectants/Antiseptics Oxidizing Agents Peroxides, ozone, and peracetic acid Kill by oxidation of microbial enzymes High-level disinfectants and antiseptics H2O2 (10-25%) can disinfect and sterilize surfaces • Not used for wounds because of catalase activity • Ozone treatment of drinking water • The combination of peracetic acid and H2O2 has been used for disinfecting hemodialyzers • 0.23% peracetic acid plus 7.35% H2O2 8. • • • • 5/9/2017 Preservatives, Antiseptics and Disinfectants 52 Peracetic Acid (40%) • Very rapid action against all microorganisms • Effective in the presence of organic matter • Sporicidal even at low temperatures • No harmful decomposition products • Leaves no residue • Corrode copper, brass, bronze, plain steel, and galvanized iron but these effects can be reduced by additives and pH modifications • Unstable particularly when diluted (1%) • Used in automated machines to sterilize medical, surgical & dental instruments (e.g., endoscopes) 5/9/2017 Preservatives, Antiseptics and Disinfectants 53 Evaluation of Biocidal action (disinfectants) • It classified into suspension tests & counting methods • Principle: Contact and removal methods: i. Contact : M.O & AMA (reaction mixture), ii. Remove samples from the reaction medium into: iii. Recovery medium in the absence of the AMA to check end point which may be : 1. Sterility: absence of living M.O (Extinction time method) 2. Change in viable count of survivors (Counting method) 5/9/2017 Preservatives, Antiseptics and Disinfectants 54 Extinction time methods • These are essentially tests for sterility upon bacterial suspensions performed after treatment with AMA for a prescribed time and under controlled conditions • They may be subdivided into 1. Phenol coefficient-type tests 2. Tests carried out at use-dilutions & test overall performance without reference to phenol. 5/9/2017 Preservatives, Antiseptics and Disinfectants 55 Phenol coefficient tests • Also called suspension tests. • Qualitative tests: Activity of disinfectant is compared with that of phenol against bacterial suspension 1. The Rideal-Walker (RW) test A set of 5 dilutions of the substance to be tested A set of 5 dilutions of phenol Both sets are inoculated with Salmonella typhi At intervals of 2.5, 5, 7.5 & 10 min, disinfectant/bacterial mixture is 'tested for sterility by subculturing a loopful into nutrient broth, which is then incubated for 48-72 hours at 370C. 5/9/2017 Preservatives, Antiseptics and Disinfectants 56 The Rideal-Walker (RW) test • Presence or absence of growth is recorded. The test itself is conducted at 17- l8oC (room temp) • The test is a special example of what is known as a phenol coefficient test • The RW coefficient is calculated from the as following formula: • • RW coefficient = Dilution of unknown which kills in 7.5 but not in 5 min. Dilution of phenol which kills in 7.5 but not in 5 min 5/9/2017 Preservatives, Antiseptics and Disinfectants RW test 57 5/9/2017 Preservatives, Antiseptics and Disinfectants 58 The Chick-Martin (CM) test • Modification of Rideal-Walker method • Done mimicking naturally: in presence of organic matter • 3% dried human faeces should be added • Garrod use dried yeast as a substitute and the test was made the subject of a British Standard (BS 808:1986). • Contact period is 30 min at 30oC • Both Salmonella typhi and S. aureus are used 5/9/2017 Preservatives, Antiseptics and Disinfectants 59 5/9/2017 Preservatives, Antiseptics and Disinfectants 60 The Chick-Martin (CM) test • Subcultures are made in duplicate into nutrient broth • Incubate for 48 h at 37oC and the presence or absence of growth noted • The concentration of phenol which prevents growth in both is determined and the mean value calculated; a similar value is obtained for the unknown. • The coefficient is calculated by dividing the value found for phenol by the value found for the unknown. 5/9/2017 Preservatives, Antiseptics and Disinfectants 61 The Chick-Martin (CM) test • If in a pair of tubes, growth is obtained in one but not the other, the concentration value corresponding to that pair is used. • A typical experimental result and the method of calculating the coefficient is shown in the following table . 5/9/2017 Preservatives, Antiseptics and Disinfectants Determination of Chick-Martin Coefficient 62 5/9/2017 Preservatives, Antiseptics and Disinfectants 63 The Chick-Martin (CM) test 1. 2. 3. 4. 5. It is sometimes difficult to compare other disinfectant with phenol as standard. In this test it was used only one M.O. as test strain. The results is numerical thus difficult to interpret. The M.O. was transferred with loop. The contact time is short. 5/9/2017 Preservatives, Antiseptics and Disinfectants 64 The AOAC test • In the USA a modification of the Rideal-Walker test have been made by United States Association of Official Analytical Chemist (AOAC). • Compare the activity of the unknown with phenol but permit the choice of the medium and utilizes 3 organisms; S. typhi, Ps. aeruginosa and S. aureus 5/9/2017 Preservatives, Antiseptics and Disinfectants 65 Capacity use-dilution test The Kelsey-Sykes (KS) test • Its triplicate challenge test, designed to determine conc of disinfectant that will be effective in clean and dirty conditions • Bacterial inoculum was added to the disinfectant in 3 successive lots at 0,1 and 5 minutes. • This is the principle of capacity test where the capacity or lack of capacity of the disinfectant to destroy successive additions of a bacterial culture is tested • It’s performed in separate repeats using: S. aureus, E. coli, Ps. aeruginosa & Proteus vulgaris. 5/9/2017 • It’s Preservatives, Antiseptics and Disinfectants 66 more realistic choice than employed test organism in RW & CM tests. • The organisms are grown on a synthetic medium and survival is tested in a broth containing the nonionic surface active agent (Tween 80). • The disinfectant reaction is at 20oC and recovery of organisms at 32oC. • Calibrated and dropping pipettes rather than loops are used for inoculation and other liquid manipulations, and disinfectants diluted at approximately the dilutions recommended for use are made in hard water. 5/9/2017 Preservatives, Antiseptics and Disinfectants 67 • The test outlined above is carried out under clean and dirty conditions (compare RW, clean, and CM, dirty), the latter being simulated by dried yeast as in the CM test. 5/9/2017 Preservatives, Antiseptics and Disinfectants 68 In summary, therefore, the KS suspension test differs from the RW and CM tests in: 1. It is a capacity test 2. It reports the data as a pass or fail and not as a coefficient 3. It uses a range of microorganisms. 4. It combines an individual feature of the RW test in that it can report on disinfectant activity under both clean and dirty conditions. 5/9/2017 Preservatives, Antiseptics and Disinfectants 69 The Criticisms of KS test • The test was suitable for white and clear, soluble disinfectants providing due care was taken on interpreting the pass concentration. • Further modification of the test is necessary before it can be applied to other disinfectants. 5/9/2017 Preservatives, Antiseptics and Disinfectants 70 ASSESSMENT OF A NEW ANTIBIOTICS • Determination of the antimicrobial spectrum • Determination of MIC • Determination of MBC • Determination of antibiotic synergism and antagonism • Microbiological assay