Biosaadavusega

Biosaadavusega refers to the fraction of an administered dose of an unchanged drug that reaches the systemic circulation. It is a key pharmacokinetic parameter used in drug development and clinical practice. For intravenous administration, the bioavailability is considered 100% because the drug is directly introduced into the bloodstream. However, for other routes of administration, such as oral, topical, or intramuscular, the bioavailability is typically less than 100% due to various factors.

Several factors influence a drug's bioavailability. These include the drug's solubility and dissolution rate, its stability in the gastrointestinal tract (for oral drugs), first-pass metabolism (metabolism in the liver or gut wall before reaching systemic circulation), and the route and rate of administration. For oral medications, the formulation of the drug (e.g., tablet, capsule, liquid) can also significantly impact its absorption and therefore its bioavailability.

Understanding a drug's bioavailability is crucial for determining the correct dosage and dosing frequency. A drug with low oral bioavailability may require a higher oral dose compared to its intravenous dose to achieve the same therapeutic effect. Conversely, drugs with high bioavailability can often be administered at lower doses. Bioavailability studies are a standard part of drug development, helping to compare different formulations, routes of administration, and to understand drug-drug interactions that might affect absorption or metabolism.