ANTI-INFECTIVE AGENTS

Roselyn A. Naranjo

Anti-infective Agent

- are drugs capable of acting against infection, by inhibiting the spread or by killing the infectious agent.

- is a general term that encompasses antibacterials, antibiotics, antifungals, antiprotozoans and antivirals.

CHEMOTHERAPHY

- is the use of chemical substances to treat disease. In its modern-day use, it refers to cytotoxic drugs used to treat cancer or the combination of these drugs into a standardized treatment regimen.

-is the use of medicines (or drugs) to treat disease.

- can destroy cancer cells that have metastasized, or spread to parts of the body far away from the primary (original) tumor.

-is the study and use of chemical agents that are selectively more toxic to the invading organism.- it is the cure of an infectious disease without injury to the host.

Cytotoxic Cells

- a cytotoxic T cell (also known as TC, CTL, T-Killer cell or killer T cell) belongs to a sub-group of T lymphocytes (a type of white blood cell) which are capable of inducing the death of infected or somatic tumor cells.

- they kill cells that are infected with viruses (or other pathogens ), or are otherwise damaged or dysfunctional.

Selective toxicity- is the property of certain chemicals to destroy one form of life without harming another.

- the cornerstone of modern antimicrobial chemotherapy.

Paul Ehrlich - discovered the antibacterial dyes and parasitic activity of organic arsenical.

Classification of chemotherapeutic Agents

1. Chemical Type

2. Biological Properties

3. Therapeutic indicators

Types of Anti-infective agent according to source:

1. Antibiotics – derived from natural source or semi-synthetically prepared. 2. Antimicrobials – produced from synthetic substances.

Classification of Local Anti-infective Agents

1. Antiseptic- are compounds that kill or prevent the growth of microorganism when applied to living tissue.

Criteria of an ideal Antiseptic

* exerts rapid and sustained lethal action against microorganism (narrow and broad spectrum)* retain activity in the presence of body fus including pus* non-irritating to tissues* non-allergenic* lack systemic toxicity when applied to skin or mucous

membrane * does not interfere with healing

2. Disinfectant- is an agent that prevents infection by the destruction of pathogenic microorganisms when applied to inanimate objects

Criteria of an ideal disinfectant

* exerts a rapid lethal action against all potentially pathogenic microorganisms and spores.

* has good penetrating power into organic matter* compatible with organic compounds (especially soap)* not inactivated by living tissues* non-corrosive* esthetically desirable (non-staining and odorless)

Classification of Local Anti-infective Agents

ALCOHOLS AND RELATED COMPOUNDS

- also known as ethanol, wine spirit, Cologne spirit.- has burning taste and flammable.- miscible with water and other organic solvents.- fermentation product from grain and other carbohydrates.- most widely abused of all recreational drugs.- metabolized in the liver to aldehyde then to acetic acid and finally to carbon dioxide and water.

A. Alcohol

Classification of Local Anti-infective Agents

The antibacterial action of alcohol is due to the denaturing effect on proteins.

100% ethyl alcohol 70% ethyl alcohol

coagulates

A. Alcohol

Uses:

- antiseptic, preservative, mild counter-irritant or solvent of pharmaceutical preparations including spirits, tinctures and fluidextracts.

- rubbing alcohol is used as astringent, rubefacient, refrigerant and mild local anesthetic.

- alleviate pain of neuralgia by injecting alcohol to nerve and ganglia.

- used internally in diluted forms as a mild sedative, as a weak vasodilator, as carminative and as source of energy.

Denatured alcohol

- is ethanol that has been rendered unfit for use in intoxicating beverages by the addition of other substance.

Completely denatured alcohol

Specially denatured alcohol- is ethanol treated with one or more substances so that its use may be permitted for specialized purposes.

Examples are methanol for plant extracts Iodine in alcohol for tincture of iodine

- contains added wood alcohol and benzene and is unsuitable for either external or internal use.

Types of alcohol

ALCOHOLS AND RELATED COMPOUNDS

B. Dehydrated Ethanol

- also known as absolute alcohol - it contains not less than 99% by weight of C2H5OH.- it is prepared by azeotropic distillation of an ethanol and benzene mixture. - it has a very high affinity of water and must be stored in tightly sealed containers. - it is use primarily as chemical agent, but it has also been injected for the local relief of pain in carcinoma and neuralgia.

ALCOHOLS AND RELATED COMPOUNDS

C. Isopropyl alcohol, USP

- it is a clear, colorless liquid having a characteristic odor and slightly bitter taste. It is considered a suitable substitute for ethyl alcohol for most external uses, but it must not be taken internally.

- it is prepared commercially by the sulfuric acid-catalyzed hydration of propylene.

Uses:        - it is rapidly bactericidal in the concentration range of 50% to 95%. - 40% concentration is considered equal in antiseptic power to a 60% ethanol concentration.

- Azeotropic isopropyl alcohol, USP is used by diabetics

To be continued…