What is log Kow value?
What is log Kow value?
Definition. “log Kow” is a ratio value without a unit and is normally used in the decadic logarithm (“log” in log Kow). This means that the smaller the log Kow, the more soluble the substance is in water. Consequently, this means the higher the log Kow, the more soluble the substance is in fatty (nonpolar) substances.
What is log P value of a drug?
Lipophilicity is a valuable parameter of the drug which affects its activity in the human body. The Log P value of the compound indicates the permeability of the drugs to reach the target tissue in the body. All the investigated compounds are lipophilic because the Log P > 0 (or P > 1) (Table 3).
What makes a drug more 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.
What makes something lipophilic?
Definition: Lipophilic or ‘lipid-loving’ molecules are attracted to lipids. A substance is lipophilic if it is able to dissolve much more easily in lipid (a class of oily organic compounds) than in water.
How does Lipophilicity affect drug distribution?
Lipophilic drugs disproportionately distribute into adipose tissue in obese subjects, causing a disproportionate prolongation of half‐life. The magnitude of the effect across drugs is significantly explained by in vitro measures of lipid‐solubility.
What does Lipophobic mean?
Lipophobicity, also sometimes called lipophobia (from the Greek λιποφοβία from λίπος lipos “fat” and φόβος phobos “fear”), is a chemical property of chemical compounds which means “fat rejection”, literally “fear of fat”. Lipophobic compounds are those not soluble in lipids or other non-polar solvents.
Are proteins lipophilic or Lipophobic?
Generally, peptides consisting of fewer than 50 amino acids are peptides and those with more are called proteins. Peptides are hydrophilic (lipophobic). Steroids are derived from cholesterol and function as hormones. All are lipophilic.
What is lipophilic and Lipophobic?
As adjectives the difference between lipophilic and lipophobic. is that lipophilic is having the quality of dissolving in lipids while lipophobic is (chemistry) having no affinity for fats or organic solvents.
What do the words hydrophilic and lipophilic mean?
Thus lipophilic substances tend to dissolve in other lipophilic substances, but hydrophilic (“water-loving”) substances tend to dissolve in water and other hydrophilic substances. …
Is blood lipophilic or hydrophilic?
However, lipophilic substances are not water-soluble, and, since blood is aqueous, this presents a challenge. The body addresses this need by using ‘carriers’ which can bind or sequester lipophilic molecules to aqueous ‘vehicles’ and thus transport them through the aqueous environment of the blood.
Why is Lipophilicity important?
Lipophilicity and drug discovery Lipophilicity is an important physicochemical parameter that contributes to the absorption, distribution, metabolism, excretion, and toxicity of a drug. This, in turn, affects the solubility and permeability of a drug and contributes to its potency and selectivity.
Why are lipophilic drugs well absorbed?
Small molecules tend to penetrate membranes more rapidly than larger ones. Most drugs are weak organic acids or bases, existing in un-ionized and ionized forms in an aqueous environment. The un-ionized form is usually lipid soluble (lipophilic) and diffuses readily across cell membranes.
Why solubility of drug is important?
Solubility is one of the important parameters to achieve desired concentration of drug in systemic circulation for achieving required pharmacological response [12]. These poorly water soluble drugs having slow drug absorption leads to inadequate and variable bioavailability and gastrointestinal mucosal toxicity.
What does a negative log D mean?
Predicted logP is 2.7 ± 0.3. Negative values of logD (-1.44 to 0) in the physiologically relevant pH range (pH 1–8) lead us to conclude that this compound would be more susceptible to higher aqueous solubility and of lower lipophilicity in the body. As a result we would expect membrane permeability to be poor.
What is the difference between log P and log D?
LogD is a distribution coefficient widely used to measure the lipophilicity of ionizable compounds, where the partition is a function of the pH. For non-ionizable compounds LogP = LogD throughout pH range, whereas for ionizable compounds LogD takes into account the partition of both ionized and non-ionized forms.
How does pH affect partition coefficient?
The partition coefficient of benzoic acid in benzene-water system was found to be 0.636 and in buffer solutions of pH 4.0, pH 7.0 and pH 9.0 were 0.841, 0.624 and 0.589 respectively. Graphically it was observed that partition coefficient of benzoic acid in acidic pH was higher than neutral and basic medium.
How is LogP measured?
Measurement of LogP can be undertaken in a variety of ways, the most common is the shake-flask method, which consists of dissolving some of the solute in question in a volume of octanol and water, shaking for a period of time, then measuring the concentration of the solute in each solvent.