CHEMOTHERAPY ANTISEPTICS AND DISINFECTANTS
ANTISEPTICS AND DISINFECTANTS • These are nonselective, anti-infective agents. • applied topically. • activity ranges from a simple santization (i.e. decreased micro-organism population) to sterilization on the applied surface. • Antiseptics have -static or -cidal effect on organism. – they are applied to tissues to prevent or suppress microbial infections
ANTISEPTICS AND DISINFECTANTS • Disinfectants are germicidal compounds usually applied to inanimate surfaces. • depending on the concentration, conditions of exposure and numbers of organisms, the same compound may act as an antiseptic or as a disinfectant. • proper concentration of the drug for the purpose intended is essential to achieve maximum efficiency. NOTE : The logic that “if a little is good, twice as much is better ” is not only uneconomical, but often has toxicological implications.
ANTISEPTICS AND DISINFECTANTS USES • Topical anti-infective agents are extensively used:- • in surgery for the antisepsis of the surgical area and surgeon’s hands, • to disinfect surgical instruments, apparel • to disinfect hospital premises, • disinfectants are used for home and farm premises, • in water treatment, • in public health sanitation • and as antiseptics in soaps, teat dips and dairy sanitizer.
ANTISEPTICS AND DISINFECTANTS • Antiseptics have also been used for treating local infections even though systemic chemotherapeutic agents are now preferred because of – better penetration of foci of infection, – less likely to lose their potency when in contact with body fluid and debris in the affected area
Properties of ideal antiseptics and disinfectants These include: - • broad spectrum and • potent germicidal activity, • rapid onset • long duration of action • activity in the presence of pus, necrotic tissue and other organic material. • high lipid solubility • good dispensability • Antiseptic should be non-toxic to the host tissue, and not impair healing • disinfectants should be non destructive to applied surfaces. • offensive odour, colour & staining properties should be absent or minimal.
Mode of Action • These agents exert their antimicrobial effect by:- • denaturation of intracellular protein, • alteration of cellular membrane, often through extraction of membrane lipids, or • enzyme inhibition
ANTISEPTICS AND DISINFECTANTS Types commonly used: 1. ACIDS and ALKALIES ACIDS • H + is bacteriostatic at pH 3 - 6 and bactericidal at pH < 3 e.g. HCl; H 2 S0 4 (0.1 to I N solution) • use limited because of their corrosiveness. USES :- • food preservative e.g. benzoic acid • antiseptics e.g. boric acid, acetic acid etc. • fungicides e.g. salicylic acid, benzoic acid etc. • spermatocides e.g. acetic acid, lactic acid • cauterizing agent (strong mineral acids )
ANTISEPTICS AND DISINFECTANTS ALKALIES • hydroxyl ion has antimicrobial activity • pH > 9 will inhibit most bacteria • e.g. NaOH and Ca(OH) 2 are employed as disinfectants.
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- Fall '19