biohasznosíthatósága

Biohasznosíthatóság is a Hungarian term that translates to bioavailability. It refers to the fraction of an administered dose of an unchanged drug that reaches the systemic circulation. This is a key pharmacokinetic parameter that influences the dose required for a drug to produce a therapeutic effect.

Several factors can affect bioavailability. For orally administered drugs, absorption from the gastrointestinal tract is a primary determinant. This can be influenced by factors such as the drug's solubility, dissolution rate, gastric emptying time, intestinal motility, and the presence of food. First-pass metabolism, where a drug is extensively metabolized by the liver before reaching systemic circulation, also significantly reduces oral bioavailability.

Intravenous administration generally results in 100% bioavailability, as the drug is directly introduced into the bloodstream. For other routes of administration, such as intramuscular, subcutaneous, transdermal, or inhalation, bioavailability can vary depending on the specific formulation and the physiological characteristics of the administration site.

Understanding bioavailability is crucial for drug development, dosage form design, and determining appropriate dosing regimens. Variations in bioavailability can lead to differences in therapeutic efficacy and potential toxicity between different formulations or even between individuals. It is often expressed as a percentage or a fraction.