ABSTRACT
Antibiotics represent a diverse group of chemotherapeutic agents with activity against microorganisms such as bacteria, fungi or protozoa. This chapter will focus primarily on the current methods to analyze drugs that are used to treat bacterial infections. Antibacterial antibiotics may be categorized [1-3] based on their target specificity: narrow-spectrum antibiotics target particular types of bacteria, such as gram-negative or gram-positive bacteria, while broad-spectrum antibiotics affect a wide range of bacteria. In addition, antibiotics can be broadly classified as either bactericidal or bacteriostatic, based on their mechanism of action [1,4]. Bactericidal agents typically kill bacteria directly, whereas bacteriostatic agents prevent cell growth and division, although there can be considerable overlap these classifications depending on the drug and organism. Typically, minimum inhibitory concentration (MIC) and minimum bactericidal concentration are used to measure in vitro activity antimicrobial and is an excellent indicator of antimicrobial potency [2]. As such, antibiotics can be further characterized as either concentration-dependent (for which achieving a large postdose concentration to MIC ratio appears important) or concentration-independent/time-dependent (where efficacy is related to maintaining the overall concentration above the MIC). Therapeutic ranges and dosage regimen can be based theoretically on its known pharmacokinetics and pharmacodynamics [2,3-6]; thus, in some clinical situations, direct monitoring of drug concentrations within serum, plasma, or other body fluids may be warranted.
