Antibiotics have some specific characteristics that distinguish them from other antimicrobial agents that are used for the treatment of microbial infections as well as in the control of microbes on inanimate surfaces. Antibiotics must possess these properties in order to be effective for in vivo usage in man or animals. Some of these features are highlighted in this unit.
- Selective Toxicity: Antibiotics must be selectively toxic as they dissipate their antibacterial properties in vivo. This means that antibiotics should kill or inhibit pathogens without causing any harm or damage to the host (patient) in anyway.
- Spectrum of Activity: Antibiotics should have a reasonable spectrum of activity (broad or narrow), showing efficacy over a given microbe or wide variety of bacteria.
- Antibiotics should not eliminate the normal microbial flora of the body as they exert their antimicrobial properties in vivo.
- They should be specific in their action. Thus, antibiotics should be readily directed to the site of infection where their effect is highly needed in the body.
- Antibiotics should not be too costly so that their prescription should not be biased or based on their price or cost.
- Antibiotics should not be easily neutralized or excreted from the body until it has performed its function. Thus, they should be chemically stable in vivo.
- Microorganisms should not become easily resistant to them.
- It should be able to exert its antimicrobial function even when highly diluted in the host’s body fluid.
- The drug should remain potent enough in vivo while releasing its antimicrobial activity.
- It should not be easily excreted from the body especially before it has performed its function.
- It should be chemically-stable and it should have a long shelf-life.
- It should not eliminate the normal flora of the host.
- It should have a wide spectrum of activity with the ability to destroy or inhibit many different species of pathogenic organisms.
- It should be nontoxic to the host and without undesirable side effects.
- It should complement the activities of the host’s immune system.
- It should remain active in tissues and body fluids.
- It should be readily delivered to the site of infection without delay.
- It should not be excessively expensive, and must be readily available.
- It should not disrupt the health status of the host by causing allergic reaction.
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