Drug distribution is affected by many factors, including plasma or tissue protein binding, body weight, body composition, and body fluid spaces (8). ... For these reasons, the volumes of distribution of lipophilic drugs are expected to be greater in women after normalization for body weight.

How are lipophilic drugs distributed?

A drug that is highly lipophilic, such as chloroquine, may readily cross the lipidic bilayer of endothelial cells and most cell membranes to reach into the intracellular space via passive transcellular diffusion.

How does lipophilicity affect drug distribution?

Lipophilicity is an important physicochemical parameter that contributes to the absorption, distribution, metabolism, excretion, and toxicity of a drug. ... This often leads to compounds that have a high rate of metabolism, leading to poor solubility, high turn-over, and low absorption.

How do lipophilic properties impact distribution?

Lipophilicity has also been found to affect a number of pharmacokinetic parameters: higher lipophilicity gives, in general, lower solubility, higher permeability in the gastrointestinal tract, across the blood–brain barrier and other tissue membranes, higher affinity to metabolizing enzymes and efflux pumps, and higher ...

How does lipophilicity affect ADME?

On the molecular level, drug lipophilicity affects drug transport through lipid cell membranes as well as drug's interactions with target protein(s). ... On the organism level, lipophilicity influences several ADME properties, like absorption, distribution into tissues, binding efficiency of a drug, etc.

Pharmacokinetics - Part 2: Lipophilic and Hydrophilic drugs

28 related questions found

How does fluorine increase lipophilicity?

Adding fluorine to biologically active organic compounds increases their lipophilicity (ability to dissolve in fats), because the carbon–fluorine bond is even more hydrophobic than the carbon–hydrogen bond. This effect often increases a drug's bioavailability because of increased cell membrane penetration.

What factors influence drug distribution?

Several factors impact drug distribution. These factors include the concentration of drug transporters in blood, pH, perfusion, body water composition, body fat composition, and most certainly disease conditions (e.g., volume depletion, burns, third spacing).

What are factors that can influence a medication's solubility in the blood?

Factors affecting Absorption of Drugs

• Lipid water solubility. Lipid water solubility coefficient is the ratio of dissolution of drug in lipid as compared to water. ...
• Molecular size. ...
• Particle size. ...
• Degree of Ionization. ...
• Physical Forms. ...
• Chemical Nature. ...
• Dosage Forms. ...
• Formulation.

Which factors affect drug distribution quizlet?

What factors affect drug distribution?
...
Pharm - Drug Distribution

• Physiological properties of drug (pKa, lipid solubility, etc.)
• Concentration gradient between blood and tissue (Bulk flow through capillary pores & simple diffusion)
• Ratio of blood flow to tissue mass (SA for drug transfer to tissue)

What makes a chemical lipophilic?

Lipophilicity refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. These non-polar solvents are themselves lipophilic (translated as "fat-loving" or "fat-liking"— the axiom that dissolves. ... Thus lipophilic substances tend to be water insoluble.

Why are lipophilic drugs well absorbed?

In general, lipid-soluble drugs, and drugs composed of smaller molecules, cross the cell membrane more easily and are more likely to be absorbed by passive diffusion.

Why are drugs lipophilic?

Lipophilicity of drug candidate molecules is a major concern in the development of its dosage form, because drug molecules must penetrate the lipid bilayer of most cellular membranes, including that of the enterocytes. Therefore, it is generally believed that drug molecules must be lipophilic to have good absorption.

How does capillary permeability affect drug distribution?

Capillary permeability: permeability of capillaries is tissue-dependent. Distribution rates are relatively slower or non-existent into the CNS because of the tight junction between capillary endothelial cells and the blood-brain barrier.

What do lipophilic drugs bind to?

Quantitative relationships between lipophilicity (characterized by the octanol-water partition coefficient) and binding to both human plasma proteins and blood cells have been studied in a group of model anionic drugs (benzoic and phenylacetic acid derivatives).

Which of following creates nonlinearity in drug distribution and not in drug absorption?

Which of the following creates nonlinearity in drug distribution and not in drug absorption? ... Nonlinearity in drug distribution occurs when saturation of binding sites on plasma proteins or saturation of tissue binding sites. 3.

How does tissue binding affect drug distribution?

For a drug that is highly tissue-bound, very little drug remains in the circulation; thus, plasma concentration is low and volume of distribution is high. Drugs that remain in the circulation tend to have a low volume of distribution.

In what way does tissue storage affect the action of drugs?

Accumulation of drugs in tissues or body compartments can prolong drug action because the tissues release the accumulated drug as plasma drug concentration decreases.

How does water solubility affect drug distribution?

Drugs that dissolve in water (water-soluble drugs), such as the antihypertensive drug atenolol, tend to stay within the blood and the fluid that surrounds cells (interstitial space). Drugs that dissolve in fat (fat-soluble drugs), such as the antianxiety drug clorazepate, tend to concentrate in fatty tissues.

What affects drug elimination?

A variety of other factors impacts elimination — intrinsic drug properties, such as polarity, size, or pH. Also, other factors include genetic variation among individuals, disease states affecting other organs, and pathways involved in the way the drug distributes through the body, such as first-pass metabolism.

Can lipophilic drugs cross the blood brain barrier?

Schematic of blood:brain barrier (BBB), brain parenchyma, and stroma. Small, unbound, lipophilic agents are able to cross the BBB. They then must cross through brain parenchyma by diffusion across the extracellular space to reach tumor cells (image by Katie Allen).

What factors affect the value of distribution coefficient?

Factors affecting Distribution Coefficient-

• The value of K depends upon the temperature , nature of solute , nature of two solvents .
• It does not depend upon the amount of solute or solvents taken.

What are the sources of fluorine?

The two most important sources of fluorine are the minerals fluorite, commercially known as fluorspar, and fluorapatite, commercially known as phosphate rock. The major consumers of fluorspar are the aluminum, chemical, and steel industries.

What is the major source of fluorine to man?

Food, together with drinking water, is the main source of fluorine for human beings. It is therefore, important to investigate the daily flourine intake derived from food.

Why is fluorine added to drugs?

Fluorine is a common element added to pharmaceuticals because it can increase the drug's selectivity, enable it to dissolve in fats, and decrease the speed at which the drug is metabolized, thus allowing it more time to work.