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Therefore, a drug given by the intravenous route will have an absolute bioavailability of 100% (f = 1), whereas drugs given by other routes usually have an absolute bioavailability of less than one. If we compare the two different dosage forms having same active ingredients and compare the two drug bioavailability is called comparative ...
Absolute bioavailability refers to the bioavailability of a drug when administered via an extravascular dosage form (i.e. oral tablet, suppository, subcutaneous, etc.) compared with the bioavailability of the same drug administered intravenously (IV). This is done by comparing the AUC of the non-intravenous dosage form with the AUC for the drug ...
The model outputs for a drug can be used in industry (for example, in calculating bioequivalence when designing generic drugs) or in the clinical application of pharmacokinetic concepts. Clinical pharmacokinetics provides many performance guidelines for effective and efficient use of drugs for human-health professionals and in veterinary medicine .
The bioavailability of those products is limited by their solvation rate. A correlation between the in vivo bioavailability and the in vitro solvation can be found. Class III – low permeability, high solubility . Example: cimetidine; The absorption is limited by the permeation rate but the drug is solvated very fast.
The absorption rate constant K a is a value used in pharmacokinetics to describe the rate at which a drug enters into the system. It is expressed in units of time −1. [1] The K a is related to the absorption half-life (t 1/2a) per the following equation: K a = ln(2) / t 1/2a. [1] K a values can typically only be found in research articles. [2]
Formulation studies then consider such factors as particle size, polymorphism, pH, and solubility, as all of these can influence bioavailability and hence the activity of a drug. The drug must be combined with inactive ingredients by a method that ensures that the quantity of drug present is consistent in each dosage unit e.g. each tablet.
The bioavailability of vaginal progesterone gel is about 40-fold greater than that of oral progesterone. [ 154 ] [ 1 ] Gel bioavailability does not seem to vary between the "Crinone 8%" formulation and two experimental generic formulations of different strengths, peaking at about 10 ng/mL after 90 mg of gel within 7 hours (with a large standard ...
The bioavailability of mianserin is 20 to 30%. [4] Its plasma protein binding is 95%. [4] Mianserin is metabolized in the liver by the CYP2D6 enzyme via N-oxidation and N-demethylation. [4] Its elimination half-life is 21 to 61 hours. [4] The drug is excreted 4 to 7% in the urine and 14 to 28% in feces. [4]